Page 2 : Fundamentals Maintenance Management, أسس إدارة الصيانة, Author:, Dr. Attia H. Gomaa, Head of Industrial Eng. Department - Fayoum University,
[email protected], , Who Should Attend:, Managers, engineers, and other practitioners concerned, with maintenance planning and control in government,, industrial and services sectors., Objectives:, To provide the participants with the modern concepts and, techniques in maintenance planning and control., To train the participants on how to use and apply these, techniques in practice., To enhance the participants experience by discussing, some maintenance management problems and how to deal, with them., Course Outline:, Level I: Traditional Maintenance Management, 1., Maintenance Management Overview, 2., Preventive Maintenance Management, 3., Maintenance Control, 4., Computer Applications, 5., PM Case Studies, 6., Machine Failure Analysis, Level II: Advanced Maintenance Management, 7., Predictive Maintenance Management, 8., Risk Based Inspection, 9., Reliability Centered Maintenance, 10. Total Productive Maintenance, 11. Practical cases., Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 2 / 150
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LEVEL I, TRADITIONAL MAINTENANCE MANAGEMENT, , 1.Maintenance Management Overview, What is Maintenance?, BS 3811:1974, Maintenance is defined as:, , , The work under taken in order to keep or restore a, facility to an acceptable standard level., , Or, The combination of activities by which a facility is kept, in, or restored to, a state in which it can perform its, acceptable standard., Maintenance Policies, “To Keep”, Planned Maintenance, - Time Based Maintenance, - Condition Based Maintenance, - Risk Based Maintenance, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , “To Restore”, Unplanned Maintenance, - Corrective Maintenance, - Run To Failure, - Emergency Maintenance, - Break down Maintenance, , 3 / 150
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Preventive maintenance - Time-based PM, , , , Pure time )calendar) based: Weekly, monthly, annually, etc., Used (running) time based: 1000 km, 1000 RH, 3000 RH, etc., , Predictive (Condition-based) Maintenance, by monitoring key equipment parameters "Off-line or On-line", Vibration analysis, Oil analysis, Wear analysis, Noise analysis, Temperature analysis, Pressure analysis, Quality analysis, Efficiency analysis, etc., , What are the main factors, which affect the, selection of Maintenance Policy?, o1, M, anufacturing maintenance recommendation, o2, System availability, o3, Safety factors, o4, Production process, o5, Operating conditions, o6, Information availability, o7, Resource availability, o8, Operating & maintenance cost, o9, Down time cost rate, o10 Failure and repair characteristics, Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 4 / 150
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What is the, Maintenance?, 1How to keep or, restore the facility at, acceptable standard, level in certain, operating conditions?, 2How to prevent the, failures?, , Example:, System/equipment description, Main parameters, Main items, Functional block diagram, Criticality, Working conditions, Main failures:, PM:, , 3How to discover the, hidden failures?, , Main failures:, Policy:, , 4How to detect the, early failures?, , Main failures:, Policy:, , 5How to minimize the, risk of failures?, , Main failures:, Risk:, Policy:, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 5 / 150
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According to maintenance, information availability:, (1), Complete, Information, , (2), Incomplete, information, , Planned PM, , Planned CM, , 70 %, , 20%, , (3), Without information, Unplanned CM, (or Emergency), 10%, , Maintenance Works, , Planned, % 70 ≤, , PM, % 45 ≤, , Repairs, % 25 ≤, , Unplanned, % 30 ≥, , Minor repairs, % 20 ≥, , Repairs, % 10 ≥, , Typical Work (man-hour) distribution in engineering industries, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 7 / 150
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Experience, , Maintenance, Planner, , Tools, , Information, , Experience:, , , , , , , , Technical, Planning, Analysis, Decision making, Problem solving, Working conditions, etc., , Information:, , , , , , , , , , , Catalog, Forms / reports, Data collection, PM levels, Job plans for each PM level, Resources, Cost rates, CM work orders, Failure analysis, etc., , Tools:, , , , , Computer programs, International standards, Management tools, etc., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 8 / 150
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What is the ratio between maintenance cost, & manufacturing costs?, Maintenance costs are a major part of the total operating costs of all, manufacturing or production plants., Depending on the specific industry, maintenance costs can represent, between 15% and 40% of the costs of goods produced., For example in food related industries, the average maintenance, cost represents about 15% of the cost of goods produced; while in, iron and steel, pulp and paper and other heavy industries, maintenance represents up to 40% of the total production costs., US industry spends more than $200 billion dollars each year on, maintenance of plant equipment and facilities,, , , USA Industries in 1983/ 1984: Maintenance Cost $ 35 * 109 Per, year, , Maintenance Cost: 10 – 25 % &, Spare parts Cost: 3 – 10 %, What are the main elements of Maintenance cost?, Direct cost:, Spare parts & supplies cost, Labor cost, Contract cost, Indirect cost:, Overhead cost, Down time cost, Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 9 / 150
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Maintenance cost = Direct cost + Overhead cost, Maintenance Costs Elements, , , , , , Cost to replace or repair, Losses of output, Delayed shipment, Scrap and rework, , Cost, , Total Maintenance Cost, PM Cost, Down Time Cost, CM Cost, Best level, , PM level, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 10 / 150
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What is Maintenance Management (MM)?, MM is a powerful systematic methodology to maximize the, facility performance and to improve the maintenance, resource productivity, through optimizing the maintenance, policies for the critical equipment., MM - is the application of knowledge, tools and scientific, techniques to identifying and analysis the maintenance, activities., MM - decision-making process to select the best, maintenance policies for improving the equipment reliability, to an acceptable level., MM is the art of matching a maintenance's goals, tasks, and, resources to accomplish a goal as needed., MM is “do the right things, with the right tools, and in the, right way"., Through:, 1. Define the target and constraints,, 2. Information collecting & analysis,, 3. Maintenance planning,, 4. Maintenance organization,, 5. Motivation & direction,, 6. Maintenance control,, 7. Corrective actions, and, 8. Learned lessons., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 11 / 150
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Maintenance Management History, 3rd generation, Higher plant, Availability &, reliability, Grater safety, , 2nd generation, 1st generation, Fix it when it, broke, , 2000, , 1990, , Higher plant availability, , Better product quality, , No damage to, Longer equipment life environment, , Preventive maintenance Longer equipment life, , 1980, , 1970, , 1960, , 1950, , How do you measure MM success?, Targets, , Customer, Satisfaction, Time, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , Cost & Resources, , 13 / 150, , 1940
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Maintenance Planning Concept:, Before you start to maintenance plan, consider..., Who is the ultimate customer?, What are the customer needs?, How long will the maintenance project last?, Where are we now?, Where should we end-up?, What are the cost constraints?, What are the technical challenges?, So, Maintenance Planning must determines what, when,, where, how, and by whom something is done., , , , , , , , What is to be maintained?, , Why?, How?, By whom?, When?, Where?, , "Description", "Target", "Method", "Resources", "Schedule", "Location", , What are the main Types of MM Plans?, 1- MM management level plans:, Master plan Top management (10 -15 activity), Action plan Control management (50-100), Detailed plan Operational management (> 500), 2- MM Time plans:, Long term, Medium term, , 2 to 10 y, 6m to 1 y, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , Risk 15 to 25%, Risk 7 to 10%, 14 / 150
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Short term, , 1w to 3 m, , Risk 3 to 5%, , 3- MM risk plans:, Target plan (normal or most likely), Optimistic plan (best case), Pessimistic plan (worst case), 4- MM Strategic Plans:, Strategic plan, Tactical plan, Operational plan, Urgent plan, 5- MM Planning Level:, Overall plan, Partial plan, Urgent plan, , “Complete information”, “Incomplete information”, “Without information”, , What is the Maintenance System?, A system is a collection of components (or items) that work, together to achieve a certain objective., , Technical Constraints Financial constraintsTargetInformationResources-, , Maintenance, processes, , Facility / Plan, at acceptable, standard, Reports-, , The output is equipment, that is up, reliable, and, Maintenance, well configured to, performance, achieve the planned, indicators, .operation of the plant, Fundamentals Maintenance Management, 15 / 150, Dr. Attia H. Gomaa
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Sub-system: Water Pump Unit, Control system, , Fluid type: Water, El. Power: 132 kw, 380 V, 3 ph, , Multi-stage, centrifugal pump, , Flow rate: 35 m3/hour, Head: 750 m, Pressure: 70 bar, , Environment, , Figure - Functional block diagram for a pump, Coupling, , Motor, , Pump, , rev/min 1800, B1, , B2, , ton/hr 35, bar 60, , Figure – Main Components, Pump specifications:Valves specifications:, Motor specifications:, Bearing specifications:, Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , Coupling specifications:, Strainer specifications:, 17 / 150
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Current PM Program:, Item, , Job plan, , Frequenc, y, , (1), Motor, (2), Coupling, , (3), Pump, (4), Suction, line, (5), Discharge, line, (6), Valves, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 18 / 150
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Root Cause Failure Analysis:, Item, , Main Failures, , Root Cause, , (1), Motor, (2), Coupling, , (3), Pump, (4), Suction, line, (5), Discharge, line, (6), Valves, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 19 / 150, , MTBF
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1) Motor:, Failure, , PM, Policy, , Freq., , PrD, Policy, , 2) Coupling:, , 3) Pump:, , 4) Suction line:, , 5) Discharge line:, , 6) Valves:, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 20 / 150, , CM, Freq.
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Developed PM Program:, Item, , Job plan, , (1), Motor, (2), Coupling, , (3), Pump, (4), Suction, line, (5), Discharge, line, (6), Valves, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 21 / 150, , Frequency
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Modern Maintenance Management Systems:, There are four modern approaches:, 1- Optimal system maintenance (OSM),, 2- Risk Based Inspection (RBI), 3- Reliability centered maintenance (RCM), and, 4- Total productive maintenance (TPM)., Maintenance management methodologies, Main, objective, Approach, , OSM, Improve, equipment, availability, Maintenance, information, analysis and, Using optimal, mathematical, modeling, , RBI & RCM, Preserve system, function & improve, system availability, Improve the, maintenance program, , TPM, Improve overall, system, productivity, System overall, analysis, , System reliability, analysis, , Continuous, improvement, techniques, , Failure mode effect, analysis FMEA, Risk analysis, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 22 / 150
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Maintenance Policies, (5 ), , ( 1), , Failure-Based, Reactive (ReM):, - RTF, - CM, - BD, (2), ::, Time-Based, Preventive (PM):, - Calendar:, Weekly, Monthly, ::, - Running:, 1000 R.H., 1000 K.M., ::, , (3), Condition-Based, Predictive (PdM):, - Oil analysis, - Vibration analysis, - Temperature analysis, - Pressure analysis, - Wear analysis, - Efficiency analysis, ::, , Total-Based, Global (GM):, - OSM, , - TPM, ::, (4), Risk-Based, Proactive (PaM):, - RCFA, - FMEA \ FMECA, - HAZOP, - RCM \ RCM2, - RBI ::, , .Figure (1): Classification of maintenance policies, [Venkatesh 2003, Waeyenberg and Pintelon 2004, and Gomaa et al. 2005], , Policy, , Approach, , Goals, , Reactive, , Run to failure (fix-it, when broke)., , Minimize maintenance, costs for non-critical, equipment., , Preventive, , Use-based maintenance Minimize equipment, program., breakdown., , Predictive, , Maintenance decision, based on equipment, condition., , Proactive, , Minimize the risk of, Detection of sources of, failures for critical, failures., systems., , Global, , Integrated approach., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , Discover hidden failures, and improve reliability, for critical equipment., , Maximize the system, productivity., , 23 / 150
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Policy, , Approach, , Goals, , RCFA, , Identification of root, causes of failures., , Eliminate failures., , FMECA, , Identification of, criticality of failures., , Improve equipment, availability., , HAZOP, , Identification of, hazards and problems, associated with, operations., , Improve HSE effect., , RCM, , Determination of best, maintenance, requirements for, critical systems., , Preserve system, function & improve, reliability., , RBI, , Determination of an, optimum inspection, plan for critical, systems., , Improve system HSE, and availability., , Policy, , Approach, , OSM, , Optimization, Maximize reliability measures, approach for the, and minimize maintenance, global maintenance, cost rates., system., , TPM, , Comprehensive, productivemaintenance, system., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , Goals, , Maximize plant effectiveness, and resource productivity., , 24 / 150
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Preventive Maintenance Management, , Why Preventive Maintenance should be done?, To Prevent Failure, To Detect Early Failure, To Discover a Hidden Failure, , Rather, it is better to consider PM only when:, 1234-, , High Down time cost rate, High Safety level, Predictive M. cannot be applied, CM cannot be justified, , What are the main targets of PM?, , , , , , , , , Improving equipment availability/reliability, Increasing equipment effective life time, Increasing resource utilization, Increasing productivity, Reducing operating cost, Reducing total cost rate, Increasing profitability ratio, , PM = Profit, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 25 / 150
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What are the main Elements of Planned, Maintenance?, 1. Inventory list, 2. Layout of facilities, 3. Facility register, 4. Maintenance program, 5. Maintenance job specification, 6. Maintenance schedule, 7. Job orders, 8. Follow up cards, 9. Performance evaluation, , Note : 1 to 5 Basic data, 6 Scheduling, and 7 to 9 Follow up and, evaluation., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 26 / 150
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Maintenance Planning Steps:, 1., , System criticality analysis, , 2., , Equipment selection, , 3., , Information collection & analysis, , 4., , Target & constraints definitions, , 5., , Requirements & standard levels, , 6., , Main failures determination, , 7., , Root cause failure analysis (RCFA), , 8., , Best maintenance policy, , 9., , Maintenance policy planning, , 10. Work orders, 11. Measure, 12. Analysis, 13. Action, 14. Performance evaluation & KPI, 15. Improvement, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 27 / 150
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Maintenance Planning Steps:, Step, 1. System criticality, analysis, 2. Equipment, selection, 3. Information, collection &, analysis, , Description, HSE - Process – Down time – Cost –, , Critical equipment, Non-critical equipment, Maintenance catalog – Design, information – Equipment historyWorking conditions- PMs – CMs –, Trouble shooting – Reliability, information – HSE instructions. etc., 4. Target &, Targets: Reliability, Availability,, constraints, Down time, Cost, HSE level, .. etc., definitions, Constraints: Budget, Spare parts,, Tools, Manpower, Information,etc., 5. Requirements & Functional levels: Flow rate, Head,, standard levels, Pressure, Power, .. etc., HSE levels, 6. Main failures, Functional failures - HSE failures –, determination, Mechanical failures – Electrical, failures - .. etc., 7. Root Cause, Main failures, Root cause, RRC,, Failure Analysis, Mechanism, Probability, MTBF,, MTTR, Remedy., 8. Best maintenance Run To Failure (RTF), policy, Time-based (Preventive) PM, Condition-based (Predictive) PdM, Risk-based (Proactive) PrM, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 28 / 150
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Maintenance Planning Steps:, Step, 9. Maintenance, policy planning, , Description, Frequency- Levels- Alarm limits- ToolsJob plan- HSE plan- Spare partsDuration- Manpower- .. etc., 10. Work orders, W/O # - W/O type- Dates/time Responsibility- Level - Alarm limitsTools- Job plan- HSE plan- Spare, parts- Duration- Manpower- Failure Root cause- .. etc., Complete Feedback., 11. Measure, Running hours- Noise- VibrationTemperature- Oil level- viscosity- Flow, rate – Head – Speed - .. etc., 12. Analysis, Noise analysis- Vibration analysis –, Temperature analysis - Oil analysis Flow rate analysis – Head analysis –, Speed analysis - .. etc., 13. Action, - Good condition, - Call for service (PM), - Call for repair (planned CM), - Breakdown (unplanned CM), 14. Performance, CM/PM- MTBF- MTTR- MTBMevaluation & KPI MTTM- Reliability – AvailabilityMaintainability- RAM- Spare parts, consumption rates- .. etc., 15. Improvement, Information – Maintenance levelsTools – Spare parts – Manpower skills, – Time – HSE - .. etc., Approach: FMEA - RCM - RBIPMIS - .. etc., Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 29 / 150
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What are the main Elements of Maintenance, Plan?, 1- Equipment name & code,, 2- Equipment priority,, 3- Maintenance start time,, 4- Maintenance down time,, 5- Maintenance level and type,, 6- Maintenance job description,, 7- Maintenance operations time,, 8- Maintenance effort (man-hour),, 9- Manpower requirements planning,, 10-, , Spare, , parts, , and, , supplies, , planning,, 11-, , Tools requirements planning,, , 12-, , Failure analysis,, , 13-, , Maintenance cost estimation,, , 14-, , Maintenance budget, and, , 15-, , Safety instructions., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 31 / 150, , requirement
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MAINTENANCE WORK ORDER, Work order number, Requester Section:, , , , , , , Plant (or department) name / code, Equipment name / code, Equipment priority, Maintenance type & level (PM / Repair / Overhaul), Job scope & description, Responsibility, , Planning Section:, , , , , , , , , Manpower types & skills, Time estimation, Spare parts, Special tools, Expected equipment down time (from xxx to xxx), Cost estimation, Safety instructions, Responsibility, , Craft Feedback:, , , , , , , , , Job scope & description, Manpower types & skills, Time estimation, Spare parts, Special tools, Actual equipment down time (from xxx to xxx), Actual Cost, Responsibility, , Coding:, Plant (or department), Equipment, Resources (Manpower, Spare parts, Special tools), , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 32 / 150
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3- Maintenance Control, Total Control Indicators:, 1- Work quantity control, Over estimation, Under estimation, 2- Time control, Behind schedule (late), Ahead schedule (early), 3- Cost control, Cost overrun, Cost under-run, 4- Quality control, Acceptable level, Non-acceptable level, 5- Inventory control, Over estimation, Under estimation, 6- Resources control, Over estimation, Under estimation, 7- Plant condition control (HSE, etc.), Acceptable level, Non-acceptable level, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 33 / 150
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Control Steps:, 1- What to control?, 2- What is the standard (target) performance?, 3- What is the actual performance level?, 4- Comparison between the actual & target., 5- Detection of variance, 6- Identification of causes of variance, 7- Corrective actions, 8- Learned lessons., Total Control Levels:, 1- Review and data collection., 2- Follow-up., 3- Performance evaluation., 4- Productivity analysis., 5- Corrective actions., 6- Learned lessons., System Effectiveness, , Efficiency, , &Utilization, Resource productivity, , Availability, , Reliability, MTBF, MTBM, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , Maintainability, MTTR, MTTM, , 34 / 150
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Maintenance Control Levels:, - Maintenance Follow-up, - (Actual/Plan), - Maintenance Performance Evaluation, -0 Time Availability, -1 Reliability, -2 Mean Time Between Failures, (MTBF), -3 Mean Time To Failures (MTTF), -4 Mean time to repair (MTTR), -5 Mean time between repairs (MTBR), -6, M, ean Time Between Maintenance, (MTBM), -7 Preventive Maintenance Rate (PM, rate), - Resources Productivity Analysis, Productivity Dimensions, Time, Quantity, Quality, Cost, Effectiveness, Efficiency, = Actual output /, 1- Technical Efficiency, Planned output, 2- Operating Efficiency, 3- Production Efficiency, 4- Economical Efficiency, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 35 / 150
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Maintenance System Effectiveness:, It is related to performance., It is the degree of accomplishment of objectives., How well a set of results is accomplished?, , Maintenance System Efficiency:, , , , , , It is related to resource utilization., It is the degree resources utilization., How well the resources are utilized to achieve, the results., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 36 / 150
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Productivity:, It is a combination of both effectiveness & efficiency., Productivity index, = Output obtained / Input expended, = Performance achieved / Resources consumed, Total productivity = Total output / Total input, Partial productivity = Total output / One of the inputs, MEASUREMENT OF MAINTENANCE EFFECTIVENESS, Equipment Losses Categories, Category, Equipment losses, Indicator, Down-time losses Equipment failures, Equipment, (lost availability), Set-up and adjustments, availability, Speed losses, Idling and minor, Equipment, (lost performance) stoppages, performance, Reduced speed operation efficiency, Defect losses, Scrap and rework, Equipment quality, (lost quality), Start-up losses, Rate, Resource losses, Critical resource, Resource, consumption rates, productivity, Cost losses, All the previous losses, Repair cost, CM/PM cost ratio, Down time cost, Overall equipment effectiveness (OEE), OEE = Equipment Availability × Performance efficiency × Quality rate, , Total effective equipment productivity (TEEP), TEEP =Utilization × Availability × Performance efficiency × Quality rate, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 37 / 150
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Net equipment effectiveness (NEE), NEE = Uptime ratio × Performance efficiency × Quality rate, , Mean unit between assists (MUBA):, MUBA = Total number of units produced / Number of stoppages, , What is the effect of Maintenance Policy on the, Equipment OEE?, Maintenance Policy, Operate to failure (RTF), , OEE, 30 – 50 %, , Good PM Program, Good bonus & incentive system, Good PM Program based on RCM, Good bonus & incentive system, , 60 – 80 %, More than 80 %, , What are the main factors, which affect the Equipment, OEE?, , , , , , , , , , Product quality, Production continuity & rates, Shutdown frequency, HSE factors, Equipment availability, Resource availability, Operating & maintenance cost, Down time cost rate, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 38 / 150
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Maintenance Risk levels:, Objective Risk Levels:, Risk %, 0-5, 5 – 10, Risk level, 0, 1, Description Minor, Low, , 10 - 15 15 - 25, 2, 3, Medium High, , Acceptable Risk limits:, Long term, 2 to 10 y, Medium term, 6m to 1 y, Short term, 1w to 3 m, , Risk 15 to 25%, Risk 7 to 10%, Risk 3 to 5%, , Maintenance Safety Levels:, Level, 0, 1, 2, , Severity, No, Very low, (Slight), Low, (Not Serious), , 3, , Medium, (Serious), , 4, , High, (Very Serious), , 5, , Very High, (Catastrophic), , Safety (people), Does not apply, Slight injury, Simple first aid, Minor injury, No lost time, No Hospitalize, First aid, Major injury, Lost time, Hospitalize, Temporary disability, Fatal injury, Hospitalize, Permanent disability, Multiple fatalities, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , > 25, 4, Major, , 39 / 150
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Maintenance Performance Evaluation, , , , , , , , , What are our measures?, What are the units?, What is the time frame?, What data is required?, What data is available?, Quality of data, Linking data to measures, , How to measure the performance of PM program?, Four major factors that should control the extent of a PM program:, 1234-, , The cost of PM program (PM & repairs costs)., Equipment reliability & utilization., HSE (Health, Safety and Environment) level, Down time cost., , S d, x 100%, S, Percentage of downtime = Id = 100% - A, , Availability = A =, , Mean time between failures = MTBF =, , S d, f, , df, , Mean time to repair MTTR = f, Where,, S = Scheduled production time, d = Downtime, f = Number of failures., df = Downtime delays from failures., Example:, Scheduled production time = 31 day, Downtime = 6 day, Number of failures = 3 failure/month, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 40 / 150
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31 6, , A = 31 x 100% = 80.6 %, Id = 100 - 80.6 = 19.4%, 31 6, MTBF =, = 8.33 days, 3, 6, MTTR=, = 2 days, 3, Maintenance Administration Indicators (%):, 1- Overtime hours per month, 2- Worker activity level, 3- Worker productivity, 4- Worker utilization, 5- Scheduled hours, 6- Preventive & predictive, Maintenance Effectiveness Indicators (%):, 1- Overall effectiveness, 2- Gross operating hours, 3- Number of failures, 4- Breakdown downtime, 5- Emergency man-hours, 6- Predictive & preventive, Maintenance Cost Indicators (%):, 1- Maintenance cost, 2- Maintenance cost/unit, 3- Maintenance manpower cost, 4- Subcontracted cost, 5- Cost of maintenance-hour, Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 41 / 150
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6- Supervision cost, 7- Preventive maintenance cost, 8- Cost of spare parts, , Main Indicators Calculations:, Overtime hours per month = % =, Total overtime hours worked, Total hours worked, , x 100, , Worker activity level = % =, Standard hours earned, Total clock time, , x 100, , Worker productivity per month = % =, Standard hours, x 100, Total hours worked, Worker utilization = % =, Hours spent on productive work, Total hours scheduled for work, , x 100, , Scheduled hours versus hours worked = %, Hours scheduled, = Total hours worked x 100, Preventive and predictive maintenance conducted as, scheduled = %=, Total man - hours of preventive and predictive maintenance executed, Total man - hours of preventive and predictive maintenance scheduled x 100, Predictive and preventive maintenance coverage% =, Total man - hours of predictive and preventive maintenance, x 100, Total man - hours worked, Overall equipment effectiveness (OEE) = A x S x Q, A = Availability indicator, Q = Quality indicator, Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , S = Speed indicator, , 42 / 150
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Availability = A =, Speed = S =, , Planned production time - Unplanned downtime, Planned production time, , Actual amount of production, Planned amount of production, , Quality = Q =, , Actual amount of production - Unaccepted amount, Actual amount, , Percentage of gross operating hours % =, Number of gross operating hours, Number of gross operating hours Downtime for maintenance, , x 100, , Number of failures in the system (NFS) =, Number of production stops, Number of gross operating hours, , Equipment downtime caused by breakdown % =, Downtime caused by breakdown, x 100, Total downtime, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 43 / 150
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Emergency man-hours % =, Man - hours spent on emergency jobs, Total direct maintenance hours worked, , x 100, , Emergency and all other unscheduled man-hours % =, Man - hours of emergency and unscheduledjobs, Total maintenance man - hours worked, , Evaluation of predictive and preventive maintenance % =, Jobs resulting from inspections, x 100, Inspections completed, Cost of maintenance to added value of production % =, Direct cost of maintenance, Added value of production, , x 100, , Maintenance cost per unit of production = Cost per unit, Total maintenance cost, = Total units produced, Manpower component in the maintenance cost % =, Total maintenance manpower, x 100, Total direct maintenance cost, Cost of subcontracted maintenance =% =, Cost of subcontracting (manpower), x 100, Direct cost of maintenance, Ratio of labor cost to material cost of maintenance =, Total maintenance labor cost, Total maintenance material cost, , Cost of maintenance-hour = $ =, Total cost of maintenance, Total man - hours worked, , Supervision cost as a percentage of total maintenance cost %=, Total cost of supervision, x 100, Total cost of maintenance, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 44 / 150
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Progress in cost reduction effects = Index =, maintenance man - hours spent on scheduled jobs, Maintenance cost/Unit of production, , Preventive maintenance (PM) cost as related to breakdown, maintenance, Total PM cost (including production losses), %=, x 100, Total breakdown cost, Inventory turnover rate per year =, Annual consumption cost, Rate = Average investment inventory, Cost of spare parts and material to maintenance cost, Total store issues and purchases, % = Total direct maintenance cost x 100, Ratio of stock value to production equipment value =, Average stock value, Replacement value of production equipment, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 45 / 150
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CMM, S, Most MMIS systems can usually:, 1., 2., 3., 4., 5., , Track components,, Provide logistic support (e.g., spares inventory),, Store maintenance history,, Alarm predetermined maintenance activities,, Produce management reports., , A small number of these systems are able to:, 6. Analyse maintenance history, and, 7. Determine “optimal’ policies for components and sub-systems., , For a complex system, MMIS will also have to:, 8., 9., 10., 11., 12., 13., , Incorporate expert opinion in a knowledge base,, Incorporate subjective data from experts,, Combine maintenance activities into schedules,, Update schedules with occurrence of events such as failures etc,, Plan resources, and, Measure the effectiveness of maintenance activities., , This requires a more quantitative and scientific approach, to maintenance management., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 47 / 150
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What is the effect of the Good Computerized Maintenance, Package?, 1- Increase labor utilization by 5 – 25 %, 2- Increase equipment utilization by 5-15%, 3- Decrease spare parts inventory by 10-20%, 4- Decrease down time cost by 5-15%, , CMMS Block diagram:, Inputs, 1- Reference data, 2- Equipment list, 3- Equipment priority, 4- PM information, 5- Resource list, 6- Working conditions, 7- CM information, 8- Cost rates, 9- Other data, 10-Actual performance, , Tool, , Outputs, 1- Maintenance labor force., , Excel, , 2- Average system availability., 3- Annual downtime cost losses., 4- Annual maintenance cost., 5- Annual PM plan., 6- Maintenance resources, 7- Monthly PM plans., 8- Maintenance work order, 9- Other reports, 10- Maintenance Control, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 48 / 150
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CMMS main Steps:, Maintenance engineering phase, Step 1: Maintenance system overview, Step 2: Maintenance system study phase, Step 3: Maintenance system conceptual design, phase, Step 4: Maintenance system detailed design phase, , Step 5: Maintenance system programming and, hardware, Step 6: Maintenance system evaluation, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 49 / 150
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5- PM Case Studies, , Case (1):, How to construct the coding & criticality systems:, , EQUIPMENT CODING, Location, Equipment Type Equipment Tag #, 1, 2, 3, 4, 7, 8, Propose a coding system and priority rules for the following, equipment:, Plant, Equipment Type Number of, Location, Systems, Machines, Productive, Turning, 4, Machining, systems, Milling, 2, shop, Drilling, 2, Grinding, 2, Press, 1, Induction furnaces, 2, Foundry, Molding machines, 5, shop, Arc Welding, 1, Welding, shop, Supportive, Fork lift, 4, Material, systems, handling, Compressor, 2, Air room, Pump – 50 HP, 2, Water, Pump – 100 HP, 2, room, Diesel generator, 2, Power, room, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 50 / 150
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Equipment Coding Structure:, Location, 1, 2, Location, 01 Machining shop, , 02 Foundry shop, 03 Welding shop, 04 Material handling, 05 Air room, 06 Water room, 07 Power room, 01, Machining shop, , 06, Water room, , Equipment Type Equipment Tag #, 3, 4, 7, 8, Equipment Type, 01 Turning, 02 Milling, 03 Drilling, 04 Grinding, 05 Press, 10 Induction furnaces, 11 Molding machines, 20 Arc Welding, 30 Fork lift, 40 Compressor, 51 Pump – 50 HP, 52 Pump – 100 HP, 06 Diesel generator, 02, Milling, , Example: 010202, 02, #2, , 52, Pump – 100 HP, , Example: 065201, 01, #1, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 51 / 150
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EIGHT LEVEL DECOMPOSITION:, Level, Characterization, 0, System, 1, Sub-System, 2, Major Assembly, 3, Assembly, 4, Sub-Assembly, 5, Component, 6, Part, 7, Material, , EQUIPMENT PRIORITY, Failure effect:, - Effect on HSE, - Effect on Production, - Effect on Cost, Failure Probability:, - Failure Frequency, Example:, Factors, 1- Production, , %, 30, , 2- HSE, , 30, , 3- Stand by, , 15, , 4- Value, , 5, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , Levels, V- Very Important, I- Important, N- Normal, V- Very Important, I- Important, N- Normal, WO- Without, WS- With Standby, H- High Value, M- Medium, L- Low, 52 / 150
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Priority, Description, Level, A, Group A: Equipment with 100% duty factor, whose, failure involves production losses and potential safety, hazards., B, Group B: Equipment with a ratio duty factor, i.e.,, having some standby, whose failure involves, production losses and potential safety hazards., C, Group C: Equipment with standby, whose failure, involves either production losses or potential safety, hazards., D, Group D: Equipment with standby, whose failure, involves neither production losses nor safety hazards., , Equipment Priorities, Location, Machining shop, , Foundry shop, Welding shop, Material handling, Air room, Water room, Power room, , Equipment Type, Turning, Milling, Drilling, Grinding, Press, Induction furnaces, Molding machines, Arc Welding, Fork lift, Compressor, Pump – 50 HP, Pump – 100 HP, Diesel generator, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 53 / 150, , Priority Level, B, B, B, B, D, A, B, A, C, C, C, C, A
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Case (2):, How to select the best maintenance policy?, Number of Engine 2000, Capital maintenance policy for engine is as follows:, Four Policies:, Replacement after first failure (after 36 month), Repair (010) after first failure & Replacement after, second failure (after 30 month), Repair (020) after second failure & Replacement after, third failure (after 24 month), Repair (030) after third failure & Replacement after fourth, failure (after 15 month), Cost rate:, Replacement $ 10,000&, , Repair $ 3,500, , Required:, Select the best maintenance policy, Estimate the annual budget for the best policy, Target maintenance plan, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 54 / 150
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Case (3):, The yearly maintenance information for ten gas, generators (GG) in a site are as follows:, 1- Working conditions for each GG:, , Average working hours 7000 hour/year, 2- PM Levels for each GG:, , Check oil level every 150 R.H. (about 2 liter), Change oil every 750 R.H. (about 20 liter), Change oil filter every 1500 R.H., 3- CM for each GG:, , 1. Average oil quantity is 100 liter/year/G.G., 4- Cost rates:, , 2. Oil cost 5 $/liter, 3. Filter cost 50 $/unit, Required:, 1. Annual materials (oil and filters) requirements, Planning., 2. Annual materials cost, 3. Annual PM plans, 4. Materials profile (histogram), 5. Maintenance work order for each PM level, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 55 / 150
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Case (4):, The yearly PM programs information for six similar gas, turbines in a power station are as follows:, 1- PM information:, Maintenance levels per gas turbine, Spare, No. of, PM Type Frequency Duration, parts Cost, Workers, $1000, Y– Level 1, Yearly, 15 days, 20, 10, S– Level 2, 6 Monthly 10 days, 20, 8, 3M– Level 3 3 Monthly, 5 days, 15, 5, M– Level 4, Monthly, 2 days, 10, 2, 2- Working conditions:, Gas turbine operating conditions: 24 hour/day, Workers operating conditions: 300 day/year & 8 hour/day, 3- CM information:, Average effort of CM = 380 man-day per gas turbine, Average annual spare parts CM = $ 12000 per gas turbine, Average CM downtime = 15 days/year per gas turbine, Average downtime cost rate = $ 1000 per day, 4- Cost rates:, Average labor cost rate = $ 10 per man-day, Overhead cost = 25 % direct cost (spare parts & labor), , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 56 / 150
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Required:, 1) The size of maintenance labor force., 2) Average system availability., 3) Annual downtime cost losses., 4) Annual maintenance cost., 5) Annual PM plan., 6) Maintenance resource profiles., 7) Monthly PM plans., 8) Maintenance work order, , The size of maintenance labor force, PM, Type, Y, S, 3M, M, , Annual Duration No. of, Man-day, Frequency, (day), Worker, per PM type, 1, 15, 20, 300 * 1= 300, 1, 10, 20, 200 * 1 = 200, 2, 5, 15, 75 * 2 = 150, 8, 2, 10, 20 * 8 = 160, , Annual PM man-day per gas turbine, Total PM annual man-day Required, , 810, 810 * 6 = 4860, , The size of PM labor force = 4860/300 =16.2 = 17 workers, The size of CM labor force = 380 * 6 / 300 = 8 workers, Total labor force = 17 + 8 = 25 workers, Crew check is ok (25 more than 20)., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 57 / 150
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The average down time per year, PM Type, Y, S, 3M, M, , Annual, Frequency, 1, , Duration, (day), 15, , PM Downtime, (day), 15 * 1= 15, , 1, 2, 8, , 10, 5, 2, , 10 * 1 = 10, 5 * 2 = 10, 2 * 8 = 16, , PM downtime per gas turbine, , 51, , Average down time = 51 + 15 = 66 day/year per gas turbine, Annual downtime cost losses = 66 * 6 * 1000 = $ 396000, Average equipment availability =, Active operating time / Total time, = (364 – 66) / 364 = 82 %, System Reliability:, Series or chain structure: Rs = R1 * R2 * R3 * … etc., Parallel structure: Rs = 1 –(1-R1)* (1-R2)* (1-R3) * .etc., System time availability =, Parallel structure: As = 1 – (1-A1)**6, = 1 – (1-0.82)**6, = 1 – (0.18)**6 = 99%, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 58 / 150
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Annual maintenance cost, PM Type, Y, S, 3M, M, , Annual, Frequency, 1, 1, 2, 8, , Cost, $1000, 10, 8, 5, 2, , Spare parts PM, Cost $1000, 10 * 1= 10, 8*1=8, 5 * 2 = 10, 2 * 8 = 16, , Annual spare parts PM per gas turbine =, 44, Total annual spare parts PM cost =, 44 * 6 = 264, The average annual spare parts CM cost =, $ 12000 * 6 = $ 72,000, Annual spare parts maintenance cost =, 264000 + 72000 = $ 336,000, Annual labor cost =, 25 workers * 300 day/year * $ 10 per man-day= $ 75,000, Annual direct maintenance cost = $ 336000 + $ 75000, = $ 411000, Overhead cost = 25 % direct cost, Annual maintenance cost = $ 411000 * 1.25 = $ 513750, Annual maintenance cost, = $ 513750, Annual downtime cost losses = $ 396000, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 59 / 150
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Basic Annual PM Plan, Eq., code, , 1, , 2, , 3, , 4, , 5, , Month #, 6, 7, , 8, , 9, , 10, , 11, , 12, , G01, G02, , Y, , M, , M, , 3M, , M, , M, , S, , M, , M, , 3M, , M, , M, , M, , M, , Y, , M, , M, , 3M, , M, , M, , S, , M, , M, , 3M, , G03, , M, , 3M, , M, , M, , Y, , M, , M, , 3M, , M, , M, , S, , M, , G04, , S, , M, , M, , 3M, , M, , M, , Y, , M, , M, , 3M, , M, , M, , G05, , M, , M, , S, , M, , M, , 3M, , M, , M, , Y, , M, , M, , 3M, , G06, , M, , 3M, , M, , M, , S, , M, , M, , 3M, , M, , M, , Y, , M, , Resource analysis:, Manday, Day/, month, Workers, SP cost, DT, , 580 230 580 230 580 230 580 230 580 230 580 230, 24, , 24, , 24, , 24, , 24, , 24, , 24, , 24, , 24, , 24, , 24, , 24, , 24, 26, 33, , 10, 18, 18, , 24, 26, 33, , 10, 18, 18, , 24, 26, 33, , 10, 18, 18, , 24, 26, 33, , 10, 18, 18, , 24, 26, 33, , 10, 18, 18, , 24, 26, 33, , 10, 18, 18, , Y= 300 S= 200, Y= 10 S= 8, Y= 15 S= 10, , 3M= 75, 3M= 5, 3M= 5, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , M= 20, M= 2, M= 2, , 60 / 150, , man-day, $1000, day
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Target Annual PM Plan # 1, Eq., code, , Month #, , 1, , 2, , 3, , 4, , 5, , 6, , 7, , 8, , 9, , 10 11 12, , G01, G02, , Y, , M, , M, , 3M, , M, , M, , S, , M, , M, , 3M, , M, , M, , M, , M, , Y, , M, , M, , 3M, , M, , M, , S, , M, , M, , 3M, , G03, , M, , 3M, , M, , M, , Y, , M, , M, , 3M, , M, , M, , S, , M, , G04, , M, , S, , M, , M, , 3M, , M, , M, , Y, , M, , M, , 3M, , M, , G05, , 3M, , M, , M, , S, , M, , M, , 3M, , M, , M, , Y, , M, , M, , G06, , M, , M, , 3M, , M, , M, , S, , M, , M, , 3M, , M, , M, , Y, , Resource analysis:, Manday, Workers, SP cost, DT, , 455 355 455 355 455 355 355 455 355 455 355 455, 19, 23, 28, , 15, 21, 23, , 19, 23, 28, , 15, 21, 23, , Y= 300 S= 200, Y= 10 S= 8, Y= 15 S= 10, , 19, 23, 28, , 15, 21, 23, , 3M= 75, 3M= 5, 3M= 5, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 15, 21, 23, , 19, 23, 28, , M= 20, M= 2, M= 2, , 61 / 150, , 15, 21, 23, , 19, 23, 28, , man-day, $1000, day, , 15, 21, 23, , 19, 23, 28
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Target Annual PM Plan # 2, Eq., code, , Month #, , 1, , 2, , 3, , 4, , 5, , 6, , 7, , 8, , 9, , 10 11 12, , G01, G02, , Y, , M, , M, , 3M, , M, , M, , M, , S, , M, , 3M, , M, , M, , M, , M, , Y, , M, , M, , 3M, , M, , M, , M, , S, , M, , 3M, , G03, , M, , 3M, , M, , M, , Y, , M, , M, , 3M, , M, , M, , M, , S, , G04, , M, , S, , M, , 3M, , M, , M, , Y, , M, , M, , 3M, , M, , M, , G05, , M, , M, , M, , S, , M, , 3M, , M, , M, , Y, , M, , M, , 3M, , G06, , M, , 3M, , M, , M, , M, , S, , M, , 3M, , M, , M, , Y, , M, , Resource analysis:, Manday, Workers, SP cost, DT, , 400 410 400 410 400 410 400 410 400 410 400 410, 17, 20, 25, , 17, 24, 26, , 17, 20, 25, , 17, 24, 26, , Y= 300 S= 200, Y= 10 S= 8, Y= 15 S= 10, , 17, 20, 25, , 17, 24, 26, , 3M= 75, 3M= 5, 3M= 5, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 17, 20, 25, , 17, 24, 26, , M= 20, M= 2, M= 2, , 62 / 150, , 17, 20, 25, , 17, 24, 26, , man-day, $1000, day, , 17, 20, 25, , 17, 24, 26
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Monthly Maintenance Plan: Month # 1, Day, 1., 2., 3., 4., 5., 6., 7., 8., 9., 10., 11., 12., 13., 14., 15., 16., 17., 18., 19., 20., 21., 22., 23., 24., 25., 26., 27., 28., 29., 30., 31., , G01, Y, Y, Y, Y, Y, Y, Y, Y, Y, Y, Y, Y, Y, Y, Y, SB, , G02, , G03, , G04, , G05, , G06, , M, M, SB, M, M, SB, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , M, M, SB, M, M, SB, M, M, SB, , 63 / 150, , PM worker, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, -
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MAINTENANCE WORK ORDER, 010120, Requester Section:, Power Station PS03 - Gas Turbine G01 - Priority: A, Maintenance type/level: Annual PM, 1- Check …., 2- Clean ….., 3- Replace ….., 4- Adjust ……, 5- Repair ….., Eng. Attia Gomaa, Planning Section:, Labor: 4 Mech. 2 Helper, 5 days, 5 Elec. 4 Helper, 10 days, Spare parts: 2 valve xx1, 4 air filter yy3, .. etc., Special tools: xxx, yyyy, … etc,, Expected down time (from 01/01 to 15/01/2004), Cost estimation ($ 10,000), Safety instructions:, - Check …, Eng. Aly Ahmed, Craft Feedback:, 1- Check …., 2- Clean ….., 3- Replace ….., 4- Adjust ……, 5- Repair ….., Labor: 3 Mech. 2 Helper, 5 days, 6 Elec., 3 Helper, 11 days, 1 Vib., 1 Helper, 2 days, Spare parts: 2 valve xx1, 4 air filter yy3, .. etc., Special tools: Vibrometer, … etc,, Down time (01/01 to 17/01/2004) Actual Cost ($ 12,000), Eng. Omer Aly, , Coding:, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 64 / 150
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Case (5):, The yearly maintenance information for three generators in, a site are as follows:, 1- Working conditions:, Two gas generators (GG01 and GG02), one operating, and the other standby, Diesel generator for emergency, Site operating hours 24/day * 365 day, 2- PM Levels (Catalog information):, Check oil level every 150 R.H. (about 2 liter), Change oil every 750 R.H. (about 20 liter), Change oil filter every 1500 R.H., Check cooling level every 150 R.H., Clean/ drain cooling system every 1500 R.H., Check and clean batteries every 1500 R.H., Lubricate bearing every 750 R.H. (about 1 liter), Change bearing every 3000 R.H., Replace thermostat every 3000 R.H., 3- CM for each GG:, Average oil quantity is 100 liter/year/G.G., 4- Cost rates:, Oil cost 3 $/liter, Filter cost 10 $/unit, Bearing oil cost 5 $/liter, Bearing cost 30 $/each, Thermostat cost 30 $/each, Required:, 1. Maintenance work order for each PM level, 2. Annual materials requirements Planning & materials cost, 3. Annual PM plans, Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 65 / 150
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4. Cost & materials profiles (histogram), , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 66 / 150
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Case (6):, Maintenance spare parts cost ($):, Year, 1999, , Year, 2000, , Year, 2001, , Year, 2002, , Exp., 2003, , 1450, , 1300, , 1200, , 1000, , ?, , 3, 1200, 3600, , 4, 1000, 4000, , X, Y, XY, , 1, 1450, 1450, , 2, 1300, 2600, , n=4, Sum X = 10, Sum Y = 4950, , Forecasting, limits, 2003, ?, 5, ?, , Sum X2 = 30, Sum XY = 11650, , Sum Y = n . a + b Sum X ,, , Sum XY = a Sum X + b Sum X2, , 4950 = 4 a + 10 b, , 11650 = 10 a + 30 b, 14850 = 12 a + 30 b, , a = 1600, , b = - 145, , Y = 1600 – 145 X, X, A, F, (A-F), (A-F)2, , Y5 = 1600 – 145 (5) = 875, 1, 1450, 1445, 5, 25, , 2, 1300, 1310, 10, 100, , 3, 1200, 1165, 35, 1225, , MSE = 1750 / (4 -1) = 583, S = 24, Z=2, , CLs = 0 ± Z S = 0 ± 48, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 67 / 150, , 4, 1000, 1020, 20, 400, , 5, 875
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Case (7):, Uncertain spare parts cost, Spare parts cost, $ 100,000, 9, 10, 11, 12, 13, , Probability, %, 20, 50, 20, 7, 3, , Estimate the spare parts budget based on the following:, 1- Average method ($ 1,100,000), 2- Probability method ($ 1,023,000), 3- PERT method ($ 1,033,000), , Solution, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 68 / 150
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MAINTENANCE SHUTDOWN PLANNING, USING CPM, Case (8): The monthly PM programs information for a, machining shop are as follows:, Machine, Code, Machine, Description, Predecessors, Duration, (day), Worker/day, Spare Parts, cost $ 1000, , T01, , D01, , M01, , T02, , M02, , Turning Drilling Milling Turning Milling, 8, , 5, , 6, , T01, 8, , M01, 20, , 5, 5, , 8, 4, , 7, 3, , 5, 6, , 5, 12, , Maximum worker limit is 12 worker/day, Required:, 1. Monthly maintenance plan., 2. Calculate the monthly spare parts cost., 3. Construct the monthly spare parts cost profile., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 69 / 150
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3- Resource Allocation, ID, , Activity, 1, , Preparation, , PRP, Mech. maintenance # 01 MM1, Elec. maintenance # 01, EM1, Mech. maintenance # 02 MM2, Elec. maintenance # 02, EM2, Mech. maintenance # 03 MM3, Elec. maintenance # 03, EM3, Setup, STP, , 2, 3, 4, 5, 6, 7, 8, , L01/, day, 2, 4, 3, 2, 2, , Resource, L02/, SPS, day, (Total), 1, 1, 5, 4, 3, 2, , 3, 4, 2, 3, 2, 3, 1, , 4- Base Calendar (Working periods), Saturday Sunday, , X, , X, , Monday, , Tuesday, , Wednesday, , Thursday, , X, , X, , X, , X, 1/01/04, , Friday, , Holidays: 20 to 21 Jan. 2004, , Required:, 1. Draw the project network (logic diagram)?, 2. Draw the corresponding Gantt chart?, 3. Construct the corresponding smoothed worker loading?, 4. Construct the corresponding worker leveling?, 5. Construct the target action plan?., 6. Construct the cost profile & S-curve?, 7. Construct the target master plan?, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 71 / 150
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3- Resource Allocation, ID, , Activity, 1, , Preparation, , 2, 3, , Server maintenance, Hardware maintenance, Lab #01, Software maintenance, Lab #01, Hardware maintenance, Lab #02, Software maintenance, Lab #02, Hardware maintenance, Lab #03, Software maintenance, Lab #03, Setup, , 4, 5, 6, 7, 8, 9, , PRP, SRM, HM1, , L01/, day, 2, , Resource, L02/, SPS, day, (Total), 1, 1, , 1, 4, , 1, -, , 1, 2, , SM1, , -, , 5, , 3, , HM2, , 3, , -, , 1, , SM2, , -, , 4, , 2, , HM3, , 2, , -, , 1, , SM3, , -, , 3, , 2, , STP, , 2, , 2, , 1, , 4- Base Calendar (Working periods), Saturday, , Sunday, , X, , X, , Monday, , Tuesday, , Wednesday, , Thursday, , X, X, X, X 1/01/04, Holidays: 20 to 21 Jan. 2004, , Required:, 1. Draw the project network (logic diagram)?, 2. Draw the corresponding Gantt chart?, 3. Construct the corresponding smoothed worker loading?, 4. Construct the corresponding worker leveling?, 5. Construct the target action plan?., 6. Construct the cost profile & S-curve?, 7. Construct the target master plan?, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 73 / 150, , Friday
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MATERIALS REQUIREMENTS PLANNING (MRP) FOR, MAINTENANCE, Case (11): A monthly maintenance plan for 50 similar, equipment to replace the gear box for these equipment. The, gear box structure is shown below., , A, B(2), D(2), , C(2), E(2), , E(2), , F(2), G(1), , Component, Lead time (week), On-Hand, , A, 1, 10, , B, 2, 15, , D(2), , C, 1, 20, , D, 1, 10, , E, 2, 10, , Required:, 1. Time-phased for the gear box structure, 2. Gross requirements plan for 50 gear box, 3. Net material requirements plan for 50 gear box., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 74 / 150, , F, 3, 5, , G, 2, 0
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Case (12): The monthly plan and the actual maintenance spare, parts in ABC Company are as follows:, Spare, part #, A11, A12, A13, A14, A15, , Plan (Jan. 2001), Planned, Standard, quantity, cost, (unit), (L.E./unit), 40, 1000, 30, 1200, 50, 900, 20, 850, 20, 950, , Actual (Jan. 2001), Actual, Actual cost, quantity, (L.E./unit), (unit), 40, 1100, 20, 1200, 40, 1000, 10, 800, 20, 900, , Based on these data, determine the different performance, indicators., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 75 / 150
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TOTAL MAINTENANCE CONTROL, Case (13):, Monthly production information on Foundry Shop FS510, was as follows:, Item, Working days, Standard production rate (ton/hr), Average daily time (hr/day), Average down time (hr/day), Average standby (hr/day), Average target quantity (ton/day), Average actual quantity (ton/day), Average sound quantity (ton/day), Average defect quantity (ton/day), Average energy consumption, (1000 kwh/day), Material cost (1000 L.E/day), , Jan., 2004, 31, 8, 24, 6, 3, 120, 80, 70, 10, 49, , Feb., 2004, 28, 8, 24, 4, 3, 136, 105, 98, 7, 67, , 100, , 130, , Based on these data, determine the different PE indicators for, the productive system., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 76 / 150
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Basic data, Item, Jan 04, Production rate (ton/hr), 8, Total time (hr/day), 24, Average down time (hr/day), 6, Average available time (hr), 18, Average standby (hr/day), 3, Average used time (hr/day), 15, Average target quantity, 120, (ton/day), Average actual quantity, 80, (ton/day), Average sound quantity, 70, (ton/day), Average defect quantity, 10, (ton/day), (14%), Energy productivity (kwh/ton) 700, Material productivity (1000, 1429, L.E/ton), , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , Feb 04, 8, 24, 4, 20, 3, 17, 136, , Feb. / Jan., 100 %, 100 %, 67 %, 111 %, 100 %, 113 %, 113 %, , 105, , 125 %, , 98, , 129 %, , 7, (7%), 684, 1326, , 64 %, , 77 / 150, , 98 %, 92 %
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Performance Evaluation, Indicator January, February, 2004, 2004, Availability, 18/24= 75 % 20/24= 83 %, , Feb. /, Jan., 111 %, , Performance, efficiency, Quality rate, , 80/120= 67 % 105/136= 77 115 %, %, 70/80= 88 % 98/105= 93 % 106 %, , Utilization ratio, , 15/18= 83 %, , 17/20= 85 %, , 102 %, , Uptime (hr/day), , 70/8= 8.75, , 98/8= 12.25, , 140 %, , Uptime ratio, , 8.75/15= 49% 12.25/17=72, %, , 147 %, , OEE, , 44 %, , 60 %, , 136 %, , TEEP, , 37 %, , 51 %, , 138 %, , NEE, , 29 %, , 52 %, , 179 %, , Energy, productivity, (kwh/ton), Material, productivity, (1000 L.E/ton), , 700, , 684, , 98 %, , 1429, , 1326, , 92 %, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 78 / 150
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Case (14):, The six-monthly maintenance costs ($1000) for a productive, system are as follows:, Target Costs:, Jan, , Feb, , Month #, Mar Apr May, , 100, 50, , 100, 50, , 100, 50, , 100, 50, , 100, 50, , 100, 50, , 100, 50, , 200, 150, 300, , 200, 150, 300, , 200, 150, 300, , 200, 150, 300, , 200, 150, 300, , 200, 150, 300, , 200, 150, 300, , Feb, , Month #, Mar Apr May, , Jun, , Jly, , 23, 32, , 38, 65, , 49, 96, , 56, 94, , 68, 94, , 65, 90, , 54, 72, , 231, 503, 407, , 213, 370, 397, , 181, 293, 320, , 185, 164, 290, , 199, 201, 330, , 196, 193, 320, , 157, 142, 362, , Cost item, PM Cost:, Spar parts, Labor, CM Cost:, Spar parts, Labor, DT Cost, , Jun, , Jly, , Actual Costs:, Cost item, PM Cost:, Spar parts, Labor, CM Cost:, Spar parts, Labor, DT Cost, , Jan, , Based on these data, determine the different performance, evaluation indicators for the maintenance system., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 79 / 150
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Target:, Cost item, PM Cost, CM Cost, TM Cost, DT Cost, TM+DT, PM/TM, CM/PM, , Jan, 150, 350, 800, 300, 1100, 0.14, 2.33, , Feb, 150, 350, 800, 300, 1100, 0.14, 2.33, , Mar, 150, 350, 800, 300, 1100, 0.14, 2.33, , Month #, Apr May, 150 150, 350 350, 800 800, 300 300, 1100 1100, 0.14 0.14, 2.33 2.33, , Jun Jly Total, 150 150 1050, 350 350 2450, 800 800 5600, 300 300 2100, 1100 1100 7700, 0.14 0.14 0.955, 2.33 2.33 16.33, , Actual:, Cost item, PM Cost, CM Cost, TM Cost, DT Cost, TM+DT, PM/TM, CM/PM, , Jan Feb Mar, 55, 103 145, 734, 583 474, 1196 1083 939, 407, 397 320, 1603 1480 1259, 0.05 0.10 0.15, 13.35 5.66 3.27, , Month #, Apr May, 150 162, 349 400, 789 892, 290 330, 1079 1222, 0.19 0.18, 2.33 2.47, , Jun Jly Total, 155 126, 896, 369 299 3208, 864 787 6550, 320 362 2426, 1184 1149 8976, 0.18 0.16 1.007, 2.38 2.37 31.82, , Change %:, Cost item, , Jan, , Month #, Feb Mar Apr May Jun, , PM Cost, CM Cost, TM Cost, DT Cost, TM+DT, PM/TM, CM/PM, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 80 / 150, , Jly, , Total
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Case (15):, The yearly PM programs information for six similar gas, turbines in a power station are as follows:, , Target work performed:, Item, Total labor force (worker), Annual spare parts cost ($1000), Annual labor cost ($1000), Overhead cost ($1000), Average down time, (day/year per gas turbine), , PM, 18, 264, --51, , CM, 7, 72, --15, , Total, 25, 336, 75, 514, 66, , Average downtime cost rate = $ 1000 per day, , Actual work performed:, Item, Total labor force (worker), Annual spare parts cost ($1000), Annual labor cost ($1000), Overhead cost ($1000), Average down time, (day/year per gas turbine), , PM, 20, 300, --45, , CM, 10, 100, --5, , Total, 30, 400, 80, 520, 50, , Based on these data, determine the different performance, evaluation indicators for the maintenance system., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 81 / 150
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Performance Evaluation Sheet:, Change, %, + 20, + 19, + 6.6, + 1.2, + 8.1, - 24.3, - 24.3, , Item, , Target, , Actual, , Total labor force (worker), Annual s. parts cost ($1000), Annual labor cost ($1000), Overhead cost ($1000), Total m. cost ($1000), Average down time, Down time cost ($1000), , 25, 336, 75, 514, 925, 66, 66, , 30, 400, 80, 520, 1000, 50, 50, , 991, 81.9, 7/18 =, 38.9, 72/264 =, 27.3, 514/411=, 1.25, , 1050, 86.3, 10/20 =, 50, 100/300 =, 33.3, 520/480=, 1.08, , + 6.0, + 5.3, + 28.5, , 25/6=, 4.17, , 30/6=, 5.00, , - 16.6, , TMC + DTC, Availability %, CM/PM % (labor force), CM/PM % (Spare parts), Overhead %, , Labor productivity %, (worker/gas turbine), , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 82 / 150, , + 22.0, - 13.6
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Case (16):, The six-monthly maintenance costs ($1000) for a productive, system are as follows:, Target Costs:, Cost item, PM Cost:, Spar parts, Labor, CM Cost:, Spar parts, Labor, DT Cost, , Jan, , Feb, , Month #, Mar, Apr May, , Jun, , Jly, , 100, 50, , 100, 50, , 100, 50, , 100, 50, , 100, 50, , 100, 50, , 100, 50, , 200, 150, 300, , 200, 150, 300, , 200, 150, 300, , 200, 150, 300, , 200, 150, 300, , 200, 150, 300, , 200, 150, 300, , Actual Costs:, Cost item, PM Cost:, Spar parts, Labor, CM Cost:, Spar parts, Labor, DT Cost, , Jan, , Feb, , Month #, Mar, Apr May, , Jun, , Jly, , 23, 32, , 38, 65, , 49, 96, , 56, 94, , 68, 94, , 65, 90, , 54, 72, , 231, 503, 407, , 213, 370, 397, , 181, 293, 320, , 185, 164, 290, , 199, 201, 330, , 196, 193, 320, , 157, 142, 362, , Based on these data, determine the different performance, evaluation indicators for the maintenance system., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 83 / 150
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Target:, Cost item, Jan, , PM Cost, CM Cost, DT Cost, TM Cost, , 150, 350, 300, 800, , Feb, , 150, 350, 300, 800, , Month #, Mar Apr May, , 150, 350, 300, 800, , 150, 350, 300, 800, , 150, 350, 300, 800, , Jun, , Jly, , 150, 350, 300, 800, , 150, 350, 300, 800, , Jun, , Jly, , 155, 369, 320, 864, , 126, 299, 362, 787, , Actual:, Cost item, , PM Cost, CM Cost, DT Cost, TM Cost, , Jan, , Feb, , 55, 734, 407, 1196, , 103, 583, 397, 1083, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , Month #, Mar Apr May, , 145, 474, 320, 939, , 150, 349, 290, 789, , 84 / 150, , 162, 400, 330, 892
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7- Machine Failure Analysis, , Parameters used for detection of machine faults, Type of fault, Out of balance, Misalignment / bent shaft, Damage of rolling bearing, Damage of journal bearing, Damage of gear box, Belt problems, Motor problems, Mechanical looseness, Resonance, xxx, xx, x, -, , Parameters, Vibration Temp., xxx, xxx, x, xxx, xx, xxx, xx, xxx, x, xx, xx, x, xxx, x, xxx, -, , High, easy and soft to measure., Medium to measure., Low to measure., Non., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 85 / 150, , Oil, x, x, xx, x, -
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Parameters used for detection of pump faults, Parameters, Vibration Temp., Out of balance, xxx, Misalignment / bent shaft, xxx, x, Damage of rolling bearing, xxx, xx, Damage of journal bearing xxx, xx, Damage of gear box, xxx, x, Belt problems, xx, Motor problems, xx, x, Mechanical looseness, xxx, x, Resonance, xxx, Minimum flow / Cavitations xxx, xx, Type of fault, , xxx, xx, x, -, , High, easy and soft to measure., Medium to measure., Low to measure., Non., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 86 / 150, , Oil, x, x, xx, x, -
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Bearing Failure Analysis, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 87 / 150
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Bearing Failure: Causes and Cures, Excessive Loads:, Excessive loads usually cause premature fatigue. Tight, fits, brinelling and improper preloading can also bring, about early fatigue failure., The solution is to reduce the load or redesign using a, bearing with greater capacity., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 90 / 150
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Overheating:, Symptoms are discoloration of the rings, balls, and cages, from gold to blue., Temperature in excess of 400F can anneal the ring and, ball materials., The resulting loss in hardness reduces the bearing capacity, causing early failure., In extreme cases, balls and rings will deform. The, temperature rise can also degrade or destroy lubricant., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 91 / 150
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True Brinelling:, Brinelling occurs when loads exceed the elastic limit of, the ring material., Brinell marks show as indentations in the raceways which, increase bearing vibration (noise)., Any static overload or severe impact can cause brinelling., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 92 / 150
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False Brinelling:, False brinelling - elliptical wear marks in an axial, direction at each ball position with a bright finish and, sharp demarcation, often surrounded by a ring of brown, debris – indicates excessive external vibration., Correct by isolating bearings from external vibration, and, using greases containing antiwear additives., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 93 / 150
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Normal Fatigue Failure:, Fatigue failure - usually referred to as spalling - is a, fracture of the running surfaces and subsequent removal, of small discrete particles of material., Spalling can occur on the inner ring, outer ring, or balls., This type of failure is progressive and once initiated will, spread as a result of further operation. It will always be, accompanied by a marked increase in vibration., The remedy is to replace the bearing or consider, redesigning to use a bearing having a greater calculated, fatigue life., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 94 / 150
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Reverse Loading:, Angular contact bearings are designed to accept an axial, load in one direction only., When loaded in the opposite direction, the elliptical, contact area on the outer ring is truncated by the low, shoulder on that side of the outer ring., The result is excessive stress and an increase in, temperature, followed by increased vibration and early, failure., Corrective action is to simply install the bearing correctly., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 95 / 150
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Contamination:, Contamination is one of the leading causes of bearing, failure., Contamination symptoms are denting of the bearing, raceways and balls resulting in high vibration and wear., Clean work areas, tools, fixtures, and hands help reduce, contamination failures., Keep grinding operations away from bearing assembly, areas and keep bearings in their original packaging until, you are ready to install them., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 96 / 150
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Lubricant Failure:, Discolored (blue/brown) ball tracks and balls are, symptoms of lubricant failure. Excessive wear of balls,, ring, and cages will follow, resulting in overheating and, subsequent catastrophic failure., Ball bearings depend on the continuous presence of a very, thin -millionths of an inch - film of lubricant between, balls and races, and between the cage, bearing rings, and, balls., Failures are typically caused by restricted lubricant flow, or excessive temperatures that degrade the lubricant’s, properties., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 97 / 150
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Corrosion:, Red/brown areas on balls, race-way, cages, or bands of, ball bearings are symptoms of corrosion., This condition results from exposing bearings to corrosive, fluids or a corrosive atmosphere., In extreme cases, corrosion can initiate early fatigue, failures., Correct by diverting corrosive fluids away from bearing, areas and use integrally sealed bearings whenever, possible., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 98 / 150
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Misalignment:, Misalignment can be detected on the raceway of the, nonrotating ring by a ball wear path that is not parallel to, the raceways edges., If misalignment exceeds 0.001 in./in you can expect an, abnormal temperature rise in the bearing and/or housing, and heavy wear in the cage ball-pockets., Appropriate corrective action includes: inspecting shafts, and housings for runout of shoulders and bearing seats;, use of single point-turned or ground threads on non, hardened shafts and ground threads only on hardened, shafts; and using precision grade locknuts., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 99 / 150
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Loose Fits:, Loose fits can cause relative motion between mating parts., If the relative motion between mating parts is slight but, continuous, fretting occurs., Fretting is the generation of fine metal particles which, oxidize, leaving a distinctive brown color. This material is, abrasive and will aggravate the looseness. If the looseness, is enough to allow considerable movement of the inner or, outer ring, the mounting surfaces (bore, outer diameters,, faces) will wear and heat, causing noise and runout, problems., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 100 / 150
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Tight Fits:, A heavy ball wear path in the bottom of the raceway, around the entire circumference of the inner ring and outer, ring indicates a tight fit., Where interference fits exceed the radial clearance at, operating temperature, the balls will become excessively, loaded. This will result in a rapid temperature rise, accompanied by high torque., Continued operation can lead to rapid wear and fatigue., Corrective action includes a decrease in total interference., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 101 / 150
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Case (17): Pump Failure Analysis, Pump Station: PS01, 8 Centrifugal pump, Failure Type: Bearing failure, Part code: xxxxx, PM every 1600 R.H. (change oil , filter and bearing), , # of, failure, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, , Bearing failures for centrifugal pumps, (Year 2004), Equipment, Run, Repair, Failure, code, time, time, Mechanism, (hr), (hr), 1007, 1250, 8, Corrosion, 1008, 1450, 6, Corrosion, 1001, 1000, 10, Temperature, 1004, 1500, 7, Corrosion, 1006, 1000, 4, Oil, 1002, 1250, 7, Corrosion, 1003, 700, 9, Oil, 1007, 600, 8, Temperature, 1008, 500, 8, Temperature, 1006, 1250, 9, Corrosion, 1001, 1000, 10, Oil, 1002, 1450, 8, Corrosion, 1005, 700, 8, Temperature, 1004, 1250, 11, Corrosion, 1005, 1000, 9, Corrosion, 1003, 700, 6, Oil, 1008, 600, 9, Temperature, 1001, 1000, 8, Oil, , Based on these data,, , Determine the different PE indicators for this system., Construct how to analyze and eliminate the bearing failure., Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 102 / 150
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Failure Analysis:, Pump Station: 8 Centrifugat pump Code: 1000, Failure Type: Bearing failure, Part code: xxxxx, (Year 2004), # of, Equipment, Run, Repair, Failure, failure, code, time, time, Mechanism, (hr), (hr), 1, 1007, 1250, 8, Corrosion, 2, 1008, 1450, 6, Corrosion, 3, 1001, 1000, 10, Temperature, 4, 1004, 1500, 7, Corrosion, 5, 1006, 1000, 4, Oil, 6, 1002, 1250, 7, Corrosion, 7, 1003, 700, 9, Oil, 8, 1007, 600, 8, Temperature, 9, 1008, 500, 8, Temperature, 10, 1006, 1250, 9, Corrosion, 11, 1001, 1000, 10, Oil, 12, 1002, 1450, 8, Corrosion, 13, 1005, 700, 8, Temperature, 14, 1004, 1250, 11, Corrosion, 15, 1005, 1000, 9, Corrosion, 16, 1003, 700, 6, Oil, 17, 1008, 600, 9, Temperature, 18, 1001, 1000, 8, Oil, Total, 18200, 145, MTBF = 18200/18 = 1011 hr, MTTR =145 /18 = 8 hr, , = 0.989 * 10-5 failure/hr, A =1011/(1011+8) =99.21%, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 103 / 150
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MTBF at which less than 20 % of the pumps are assumed to fail, Run time, Frequency, Cumulative, C.F., hr, Frequency, %, 1500, 1, 1, 5.56, 1450, 2, 3, 16.67, 1250, 4, 7, 38.89, 1000, 5, 12, 66.67, 700, 3, 15, 83.33, 600, 2, 17, 94.44, 500, 1, 18, 100, 1000 66.67, ?, 80.00, MTBF = 760 hr, 700, 83.33, Max. running time =1650 hr. Min. running time= 300 hr, Run time, hr, 1650-1400, 1400-1150, 1150-900, 900-650, 650-300, , Frequency, 3, 4, 5, 3, 3, , Mid, point, 1525, 1275, 1025, 775, 475, , C.F., 3, 7, 12, 15, 18, , C.F., %, 16.67, 38.89, 66.67, 83.33, 100, , Freq, 6, 5, 4, 3, 2, 1, 300, 650, , 650, 900, , 900, 1150, MTBF, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 1150, 1400, , 104 / 150, , 1400, 1650
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Equipment Level:, Equipment, code, 1001, , 1002, , 1003, , 1004, , 1005, , 1006, , 1007, , 1008, , Average, , MTBF, (hr), 1000, 1000, 1000, 1000, 1250, 1450, 1350, 700, 700, 700, 1500, 1250, 1325, 700, 1000, 850, 1000, 1250, 1125, 1250, 600, 925, 1450, 500, 600, 850, 1011, , MTTR, (hr), 10, 10, 8, 9.33, 7, 8, 7.5, 9, 6, 7.5, 7, 11, 9, 8, 9, 8.5, 4, 9, 6.5, 8, 8, 8, 6, 8, 9, 7.66, 8, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , A, %, , Failure, Mechanism, Temperature, Oil, Oil, , 99.00, Corrosion, Corrosion, 99.44, Oil, Oil, 98.94, Corrosion, Corrosion, 99.33, Temperature, Corrosion, 99.01, Oil, Corrosion, 99.43, Corrosion, Temperature, 99.14, Corrosion, Temperature, Temperature, 99.10, 99.21, , 105 / 150, , Corrosion, 8, Oil, 5, Temperature 5
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Failure Mechanism Level:, Failure, Mechanism, Corrosion, , Oil, , Temperature, , Average, , MTBF, (hr), 1500, 1450, 1450, 1250, 1250, 1250, 1250, 1000, 1000, 1000, 1000, 700, 700, , MTTR, (hr), 7, 8, 6, 8, 7, 9, 11, 9, 4, 10, 8, 9, 6, , 1000, 700, 600, 600, 500, , 10, 8, 8, 9, 8, , 1011, , 8, , Ranges, MTBF, 1000 1500, MTTR, 6 – 11, MTBF, 700 1000, MTTR, 4-10, MTBF, 500 1000, MTTR, 8-10, 99.21, , Equipment code, 1004, 1002, 1008, 1007, 1002, 1006, 1004, 1005, 1006, 1001, 1001, 1003, 1003, 1001, 1005, 1007, 1008, 1008, Corrosion, 8, Oil, 5, Temperature 5, , Remedy:, Maintenance Policy, Condition Based, Time Based, Every 300 hours, (1) Change oil every 600 hour, Oil analysis, (2) Change bearing & oil every, Temperature analysis, 1200 hour, Vibration analysis, Down time: (1) 1 hr & (2) 8 hr, Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 106 / 150
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Cost Analysis:, Cost elements:, Spare parts cost = 1000 L.E./failure, PM impact = 2000 L.E./failure, CM impact = 4000 L.E./failure, Parameter, PM frequency (failure/year), CM frequency (failure/year), Spare parts cost (1000 L.E. / year), PM impact (1000 L.E. / year), CM impact (1000 L.E. / year), PM & CM impact (1000 L.E. /, year), Total cost (1000 L.E. / year), , Current, 18, 18, 72, 72, , Proposed, 18, 1, 19, 36, 4, 40, , 90, , 59, , Cost ratio %, Cost saving %, , 100, -, , 65.5, 34.5, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 107 / 150
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Maintenance Policy:, I- Vibration analysis:, 1- Frequency: Every 300 Running Hours, 2- Tool:, Vibration Equipment: accelerometers, charge amplifier, and analyser., Computer program for trend analysis and prediction., 3- International Standard: CDA/MS/NVSH107, 4- Method:, 1. Record the vibration spectrum, specify the peaks, corresponds to the bearing components, 2. Record each component peak and frequency., 3. By using the soft ware and the standard limits,, determine the trend of each peak., 4. Determine the bearing state(good –need service –need, change), 5- Limits: According to CDA/MS/NVSH107, 1. Pre-failure: vibration level≤5.6 m/s, 2. Failure: vibration level 5.6≥10 m/s, 3. Near catastrophic failure: vibration level >10 m/s, 6- Actions:, 1. Bearing is Good, 2. Call for bearing change, 3. Bearing must be changed immediately, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 108 / 150
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II- Temperature analysis:, 1- Frequency: Every 300 Running Hours, 2- Tool:, Temperature measuring equipments as thermocouple or, infrared camera., Computer program for trend analysis and prediction., 3- International Standard: SKF, 4- Method:, Measure the temperature of the bearing on line and take, the average value every day., By using the software analyze the data, determine the, max. & average temperature values., According to the allowable range specified in SKF, standard, determine the bearing state., 5- Limits: According to CDA/MS/NVSH10, 1. Pre-failure: ( ≤100 ◦C), 2. Faiulre: (100 ≥125 ◦C), 3. Near catastrophic failure: (>125 ◦C), 6- Actions:, 1. Bearing is good, 2. Call for bearing change, 3. Bearing must be changed immediately, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 109 / 150
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III- Oil analysis:, 1- Frequency: Every 300 Running Hours, Viscosity change, Acidic content, Wear rate, 2- Tool:, Viscometer, PH meter, and particle counter, Computer program for trend analysis and prediction., 3- International Standard: ASTM-445 & 664 & 398, 4- Method:, Take a suitable oil sample volume, to be used in, analyses After each 300 hours., Put it in a closed container, isolated from air, heat and, contamination exposes., Measure the previous mentioned properties then enter, the obtained data to the software to be trended., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 110 / 150
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5- Limits:, Viscosity: according to ASTMD-445:, 1., 2., 3., , Pre-failure: Viscosity change <<+40% &(-)25%, Faiulre: Viscosity change ≤+40% &-25%, Near catastrophic failure: > +40% &-25%, , Acidic content: according to ASTMD-664:, 1., 2., 3., , Pre-failure: Content <<1 mg/g, Faiulre: Content ≤1 mg/g, Near catastrophic failure: Content >1 mg/g, , Wear rate: according to ASTMD-398, 1., 2., 3., , Pre-failure: Wear particles <<5% of the sample weight, Faiulre: Wear particles ≤5%, Near catastrophic failure: Wear particles >5%, , 6- Actions:, 1. Oil is Good, 2. Call for oil change, 3. Oil must changed immediately, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 111 / 150
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LEVEL II, ADVANCED MAINTENANCE MANAGEMENT, 7- PREDICTIVE MAINTENANCE PLANNING, , What is the Predictive Maintenance?, Predictive (Condition-based) Maintenance is a management, technique that uses regular evaluation of the actual operating condition, of equipment (or production system) to optimize total plant operation., In reality, predictive maintenance is a condition-driven preventive, maintenance program., Predictive (Condition-based) Maintenance, In predictive maintenance, machinery conditions are periodically, monitored and this enables the maintenance crews to take timely, actions, such as machine adjustment, repair or overhaul, It makes use of human sense and other sensitive instruments,, such as audio gauge, vibration analyzer, amplitude meter,, pressure, temperature and resistance strain gauges etc., Unusual sounds coming out of a rotating equipment predicts a, trouble, An excessively hot electric cable predicts a trouble, Simple hand touch can point out many unusual equipment, conditions and thus predicts a trouble, Predictive (Condition-based) Maintenance, by monitoring key equipment parameters "Off-line or On-line", Vibration analysis,, Oil analysis, Wear analysis,, Noise analysis, Temperature analysis, Pressure analysis,, Quality analysis, Efficiency analysis, Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 112 / 150
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Figure - Ultrasonic Detection and Analysis, The Benefits of Predictive Maintenance:, Predictive maintenance can reduce the number of unexpected failures, and provide a more reliable scheduling tool for routine preventive, maintenance tasks., Including predictive maintenance in a total plant management program, will provide the ability to optimize the availability of process, machinery and greatly reduce the cost of maintenance., The premise of predictive maintenance is that regular monitoring of the, actual mechanical condition of machine trains and operating efficiency, of process systems will ensure the maximum interval between repairs;, minimize the number and cost of unscheduled outages created by, machine-train failures and improve the overall availability of operating, plants., A survey of 500 plants that have implemented predictive maintenance, methods indicates the following:, substantial improvements in reliability, availability and operating, costs., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 113 / 150
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major improvements can be achieved in: maintenance costs,, unscheduled machine failures, repair downtime, spare parts, inventory, and both direct and in-direct overtime premiums., a dramatic improvement in: machine life, production, operator, safety, product quality and overall profitability., the actual costs normally associated with the maintenance, operation were reduced by more than 50%., reductions of 90% of failures can be achieved using regular, monitoring of the actual machine condition., The average improvement in mean-time-to-repair, MTTR, was a, reduction of 60 %., The ability to predict machine-train and equipment failures and, the specific failure mode provided the means to reduce spare, parts inventories by more than 30%, Prevention of catastrophic failures and early detection of incipient, machine and systems problems increased the useful operating life, of plant machinery by an average of 30%., The process availability was increased by about 30%., One example of this type of improvement is a food, manufacturing plant that made the decision to build additional, plants to meet peak demands. An analysis of existing plants,, using predictive maintenance techniques, indicated that a 50 per, cent increase in production output could be achieved simply by, increasing the operating efficiency of the existing production, process., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 114 / 150
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Data acquired as part of a predictive maintenance program can be, used to schedule and plan plant outages. Predictive data can, provide the information required to plan the specific repairs and, other activities during the outage., One example of this benefit is a maintenance outage scheduled, to rebuild a ball mill in an aluminum foundry. The normal outage,, before predictive maintenance techniques were implemented in, the plant, to completely rebuild the ball mill was three weeks and, the repair cost averaged $300,000. The addition of predictive, maintenance techniques as an outage-scheduling tool reduced the, outage to five days and resulted in a total savings of $200,000., The predictive maintenance data eliminated the need for many of, the repairs that would normally have been included in the, maintenance outage. Based on the ball mill’s actual condition,, these repairs were not needed. The additional ability to schedule, the required repairs, gather required tools and plan the work, reduced the time required from three weeks to five days., A side benefit of predictive maintenance is the automatic ability, to monitor the mean-time-between-failures, MTBF. This data, provides the means to determine the most cost-effective time to, replace machinery rather than continue to absorb high, maintenance costs., Predictive maintenance will automatically display the reduction, of MTBF over the life of the machine. When the MTBF reaches, the point that continued operation and maintenance costs exceed, replacement cost, the machine should be replaced., The long-term objectives of a predictive maintenance, program are to:, Eliminate un-necessary maintenance, Reduce lost production caused by failures, Reduce repair parts inventory, Increase process efficiency, Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 115 / 150
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, , , , , , Improve product quality, Extend operating life of plant systems, Increase production capacity, Reduce overall maintenance costs, Increase overall profits., , The Benefits of Predictive Maintenance: A-Z, Uptime, Inc composed a list of benefits of vibration analysis, in particular and predictive maintenance in general found in, trade magazine articles, ads, flyers, and brochures., They are as follows:, A. Minimizes or eliminates costly downtime - increases profitable, uptime., B. Minimizes or eliminates catastrophic machinery failures damage from catastrophic failure is usually much more, extensive than otherwise would have been., C. Reduces maintenance costs., D. Reduces unscheduled maintenance - repairs can be made at, times that least affect production., E. Reduces spare parts inventories - many parts can be purchased, just in time for repairs to be made during scheduled machinery, shutdowns.., F. Optimizes machinery performance - machinery always operates, within specifications., G. Reduces excessive electric power consumption caused by, inefficient machinery performance - saves money on energy, requirements., H. Reduces need for standby equipment or additional floor space to, cover excessive downtime - less capital investment required, for equipment or plant., I. Increases plant capacity., J. Reduces depreciation of capital investment caused by poor, machinery maintenance - well maintained machinery lasts, longer and performs better., K. Reduces unnecessary machinery repairs - machines are repaired, only when their performance is less than optimal., Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 116 / 150
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L. Minimizes or eliminates the possibility that machinery repairs, were the wrong repairs., M. Reduces the number of dissatisfied customers or lost customers, due to poor quality - with less than optimal machine, performance, quality always suffers., N. Reduces rework of goods caused by machines operating at less, than optimal condition., O. Reduces scrap caused by poorly performing machinery., P. Reduces overtime required to make up for lost production due to, broken down or poorly performing machinery., Q. Reduces penalties that result from late deliveries caused be, broken down or poorly performing machinery., R. Reduces warranty claims due to poor product quality caused by, poorly performing machinery., S. Reduces the possibility of accepting recently purchased new or, used machinery with defects - the invoice is not paid until the, defects are corrected., T. Increases the likelihood that newly purchased new or used, machinery meets specifications., U. Increases machinery safety - injuries are often caused by poorly, performing machinery., V. Reduces safety penalties levied against a company for unsafe, machinery., W. Reduces insurance rates because well maintained machinery, increases safety., X. Reduces the time required to make machinery repairs - advance, notice of machinery condition permits more efficient, organization of the repair process., Y. Increases the speed that machinery can be operated, if, desirable., Z. Increases the ease of operation of machinery., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 117 / 150
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Advantages & Disadvantages Of PdM:, Advantages:, Assures equipment reliability., Assures maximum machinery availability., Assures that assets are maintained in optimum condition at, maximum value., The cost of spare parts inventory can be reduced in some, cases because of the ability to forecast failures sufficiently, in advance to secure parts on an as needed basis., Can be used to assist in troubleshooting complex rotor, dynamics issues., Evaluate the quality of equipment prior to purchase., Assures the quality of new equipment installation., Assures the quality of equipment repairs., Evaluate the condition of used machinery prior to purchase., Minimizes the potential for litigation due to equipment, failure., Disadvantages:, The cost of supporting a PdM program is signification but, hopefully offset by the advantages., The quality of PdM service is not assured. Many companies, with in-house programs do not obtain the full benefit of, PdM due to inadequate funding, training, tooling, etc. PdM, contractors vary considerably in capability. Being of, technical nature, it is very easy for the inexperience to, award contracts to firms that cannot deliver quality service., Predictive Maintenance techniques do not always detect, imminent failures., , Spectra Quest provides vibration related PdM consulting, services and training., The listing of plant equipment should be ordered into the, following classes depending on their impact on, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 118 / 150
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production capacity or maintenance cost: essential,, critical, serious, others., Class I or essential machinery or equipment, must be on-line for continued plant operation. Loss, of any one of these components will result in a plant, outage and total loss of production. Plant equipment, that has excessive repair costs or repair parts leadtime should also be included in the essential, classification., Class II or critical machinery would severely limit, production capacity. As a rule-of thumb, loss of, critical machinery would reduce production capacity, by 30 per cent or more. Also included in the critical, classification are machines or systems with chronic, maintenance histories or that have high repair or, replacement costs., Class III or serious machinery include major, plant equipment that do not have a dramatic impact, on production but that contribute to maintenance, costs. An example of the serious classification would, be a redundant system. Since the inline spare could, maintain production, loss of one component would, not affect production. However, the failure would, have a direct impact on maintenance cost., Class IV machinery would include other plant, equipment that has a proven history of impacting, either production or maintenance costs., All equipment in this classification must be evaluated, to determine whether routine monitoring is costeffective. In some cases, replacement costs are lower, than the annual costs required to monitor machinery, Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 119 / 150
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in this classification. The completed list should include, every machine, system or other plant equipment that, has or could have a serious impact on the availability, and process efficiency of your plant. The next step is, to determine the best method or technique for cost, effectively monitoring the operating condition of each, item on the list. To select the best methods for regular, monitoring, you should consider the dynamics of, operation and normal failure modes of each machine, or system to be included in the program. A clear, understanding of the operating characteristics and, failure modes will provide the answer to which, predictive maintenance method should be used., , Maintenance Cost per Horsepower for General Rotating, Machinery*, Predictive Maintenance Stages:, Failure Analysis, Maintenance Policy, Detection, Analysis, Correction, Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 120 / 150
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Inspection Policy Planning & Control:, 12345678910111213-, , Best Method (vibration analysis, .. etc.), Best Frequency (inspection interval), Best Locations, Best Tools, International Standard (ISO10816, .. etc.), Standard Limits, Severity Chart, Trouble Shooting Chart, Reference Creation, Regular Measurements (monthly, .. etc.), Analysis, Decision Making, Corrective Actions, Good conditions,, Routine Maintenance,, Repair, or, Replace., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 122 / 150
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Viberation Analysis, Vibration analysis is the dominant technique used for, predictive maintenance management. Since the greatest, population of typical plant equipment is mechanical, this, technique has the widest application and benefits in a, total plant program., This technique uses the noise or vibration created by, mechanical equipment and in some cases by plant, systems to determine their actual condition., Using vibration analysis to detect machine problems is, not new. During the 1960s and 70s, the US Navy,, petrochemical and nuclear electric power generating, industries invested heavily in the development of, analysis techniques based on noise or vibration that, could be used to detect and identify incipient, mechanical problems in critical machinery., By the early 1980s, the instrumentation and analytical, skills required for noise-based predictive maintenance, were fully developed., These techniques and instrumentation had proven to be, extremely reliable and accurate in detecting abnormal, machine behavior. However, the capital cost of, instrumentation and the expertise required to acquire, and analyze noise data precluded general application of, this type of predictive maintenance. As a result, only the, most critical equipment in a few select industries could, justify the expense required to implement a noise-based, predictive maintenance program., Monitoring the vibration from plant machinery can, provide direct correlation between the mechanical, condition and recorded vibration data of each machine, Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 123 / 150
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in the plant. Any degradation of the mechanical, condition within plant machinery can be detected using, vibration-monitoring techniques. Used properly,, vibration analysis can identify specific degrading, machine components or the failure mode of plant, machinery before serious damage occurs., , Figure - Vibration severity, , Figure - Condition monitoring options for turbo charger, Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 124 / 150
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Vibration Sources, M e c h a n ic a l, Lo o se n e s s, S lo t F r e q u e n c y /, E M re la te d, , U n b a la n c e, , B e n t S h a ft, G e a rs, , B la d e P a s s /, F lu id R e la t e d, , A lig n m e n t, , M o to r, M e c h a n ic a l, Resonances, , J o u r n a l ( F lu id F ilm ), B e a rin g s, C o u p lin g s, , R o llin g E le m e n t, B e a rin g s, , S a m Sh e a rm a n, N a tio n a l In s tru m e n t s, , Accelerometer Location, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 126 / 150
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Time Domain, , Blade Pass, Motor EM, Force, , Rotation, , Power Spectrum, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 127 / 150
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Tool Selection:, Vibrometer, > 2.5, , Accelerometer, w/wn, <0.33, The percentage error, <= 0.5 %, w = measured frequency, wn= Natural frequency, The percentage error: % e = 100 (1 – MF), MF = (w/wn) / [ (1 – (w/wn)2)2 + (2 z w/wn)2 ]0.5, z = damping ratio, , Case (20):, A vibrometer of 10 Hz natural frequency and 0.68 damping, ratio is used to measure the vibration of a machine with, frequency 15 Hz., 1- Is this a successful selection for the measuring, transducer? Why?, 2- What is the percentage error in the measured vibration?, w/wn = 15 / 10 = 1.5, So, it is not a successful selection., The percentage error: % e = 100 (1 – MF), MF = (w/wn) / [ (1 – (w/wn)2)2 + (2 z w/wn)2 ]0.5, w/wn = 1.5, z = damping ratio = 0.68, MF = 0.94, %e = 100 (1 – 0.94) = 6 %, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 129 / 150
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ISO 2372-Vibration Severity Rang Limits, (Velocity), Standard Number: BS 4675:Part 1:1976, ISO 2372-1974, Title: Mechanical vibration in rotating machinery. Basis for specifying, evaluation standards for rotating machines with operating speeds from, 10 to 200 revolutions per second, Abstract: Explanatory introduction, terms and definitions, guidance on, measuring conditions, table of preferred vibration severity ranges and, examples of a recommended method of classification., Status: Withdrawn, Superseded, Publication Date: 31 March 1976, International Relationships: ISO 2372 Identical, Amended By: AMD 4739 published 29 March 1985 Price on, application, Withdrawn On: 15 May 1996, Replaced By: BS 7854-1:1996, Descriptors: Vibration, Rotating parts, Rotating electric machines,, Electric machines, Machine tools, Vibration testing, Vibration intensity,, Testing conditions, Seatings, Grades (quality), , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 130 / 150
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ISO 2372-Vibration Severity Range Limits, (Velocity), mm/Sec, (RMS), 0.28, 0.45, 0.71, 1.12, 1.80, 2.80, 4.50, 7.10, , Machines Belonging to:, Class I, < 20 HP, A, , Class II, 20-100, A, , Class III, >100 HP, , Class IV, >100 HP, , A, , A, (Good), , B, B, B, , C, C, , C, , 11.2, 18.0, 28.0, 45.0, 71.0, , D, , A: Good B: Allowable, , D, , D, , C: Tolerable, , B, (Allowable), C, (Tolerable), D, (Not, Permissable), , D: Not Permissible, , Suggested Classifications:, Class I: Small (up to 15kW) machines and subassemblies of larger machines., Class II: Medium size (15kW to 75kW) machines without special, foundations, or machines up to 300kW rigidly mounted on special, foundations., Class III: Large rotating machines rigidly mounted on foundations which, are stiff in the direction of vibration measurement., Class IV: Large rotating machines mounted on foundations which are, flexible in the direction of vibration measurement., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 131 / 150
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Re: ISO STANDARD 2372, From: Arne, Remote Name: 62.127.42.150, , Comments, , ISO 2372 is still valid for power below 15 kW. The "new" standard is, called ISO 10816 and has several parts. The part /1 outlines the basics, and the connection to older and newer standards. Part /3 is the essential, part for all general production machinery such as fans, pumps etc. In, general, as compared to older levels back to Rathbone or VDI 2056 /, Iso 2372, the levels are reduced from what was the red limit before, down to approx. half and the lowest levels called just "A" are a slight, bit higher but have aquired firm statements like "Delivery status",, much stronger recommendation than just an "A". Reciprocating /, piston och screw volume machines had Class 5 in ISO 2372 but these, levels are lost in 10816 with a very soft talk about asking the user to, please report back to ISO about experiences. That has cause this part to, be useless and old 2372 Class 5 for such machinery is used a lot here., Meaning in clear text that 4.5 mm/s rms is delivery "green" level unless, technically motivated to be something else. Frequency range is now, expanded to cover those frequencies that are relevant, instead of the, 10-1000 Hz that was used in 2372. Unit is still mm/s rms (rms is true, rms, not just an average using a diode and a capacitor in the, instrument). Regards Arne, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 132 / 150
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Canadian specification CDA/MS/NVSH107, The vibration levels (mm/s), Machine, type, Pumps, Over 5 HP, Up to 5 HP, Gear boxes, Over 10,000 HP, 10 – 10,000, up to 10, Boilers (Aux.), Fans, Below 1800 rpm, Above 1800 rpm, Diesel generator, Centrifuges,, Oil separators, Compressor, Free piston, HP air, LP air, Refridge, , New machine, Worn machine, Long life Short life Call for Immediate, > 1000 hr <= 1000 hr service, repair, 1.4, 0.79, , 5.6, 3.2, , 10, 5.6, , 18, 10, , 1.0, 0.56, 0.32, 1.0, , 10, 5.6, 3.2, 3.2, , 18, 18, 10, 5.6, , 32, 32, 18, 10, , 1.0, 0.56, 1.4, 1.4, , 3.2, 3.2, 10, 10, , 5.6, 5.6, 18, 18, , 10, 10, 32, 32, , 10, 4.5, 1.4, 0.56, , 32, 10, 5.6, 5.6, , 32, 10, 10, 10, , 56, 18, 18, 18, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 133 / 150
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Canadian specification CDA/MS/NVSH107, The vibration levels (mm/s), Machine, type, Gas turbines:, Over 20,000 HP, 6,000 – 20,000, up to 5,000, Steam turbines:, Over 20,000 HP, 6,000 – 20,000, up to 5,000, Motor generator, sets, Electrical, motors, (Over 5 HP or, below 1200 rpm), (Up to 5 HP or, above 1200 rpm), Transformers, Over 1 KVA, Up to 1 KVA, , New machine, Worn machine, Long life Short life Call for Immediate, > 1000 hr <= 1000 hr service, repair, 7.9, 2.5, 0.79, , 18, 5.6, 3.2, , 18, 10, 5.6, , 32, 18, 10, , 1.8, 1.0, 0.56, 1.0, , 18, 5.6, 3.2, 3.2, , 18, 18, 10, 5.6, , 32, 32, 18, 10, , 0.25, , 1.8, , 3.2, , 5.6, , 0.14, , 1.8, , 3.2, , 5.6, , 0.14, 0.10, , -, , 0.56, 0.32, , 1.0, 0.56, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 134 / 150
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Vibration Trouble Shooting Chart, Nature of fault, Rotating members out of, balance, Misalignment &, Bent shaft, Damaged rolling, Elements bearing, (ball, roller, etc.), , Frequency of Dominant, Vibration (Hz=rpm/60), 1 * rpm, (1 to 2) * rpm, Impact rates for the individual, bearing component. *, Vibration at high frequencies, (2 to 60 kHz), (1/2 to 1/3) rpm, , Journal bearings, loose in housing, Oil film whirl or, Slightly less than half shaft, Whip in Journal bearings speed (42 to 48%), Mechanical looseness, 2 * rpm, *Impact rates f(Hz):, n = number of balls,, Bd = ball diameter mm,, Pd = Pitch circle diameter mm, β= Angle, 1- The frequency of vibration due to outer race defect:, f = (n/2) (rpm/60) (1 – (Bd/Pd) cos β, 2- For inner race defect, f = (n/2) (rpm/60) (1 + (Bd/Pd) cos β, 3- For ball defect, f = (Bd/Pd) (rpm/60) (1 – ((Bd/Pd) cos β)2), , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 135 / 150
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Case (21):The vibration reading of a 2000 rev/min, fan is defined by:, hours 100 200 300 400 500 600 700 800 900, mm/s 0.58 1.08 1.58 2.08 2.58 3.08 3.58 4.08 4.58, Required:, 1- Construct the vibration trend., 1- Predict the vibration level at time 110 running hours., 2- Using the Canadian specification CDA/MS/NVSH107,, predict the time to “call for service” and to “immediate repair”, starting from the last measurement (at t1), 1- The vibration trend:, V = 0.08 + 0.005 t, , mm/s, Where t is in hours., , 1- The the vibration level at time 110 running hours, V = 0.08 + 0.005 (110) = 0.63 mm/s, 2- Canadian specification CDA/MS/NVSH107:, at 2000 rpm:, The vibration level of the time to “call for service” = 5.6, mm/s, The vibration level of the time to “immediate repair” = 10, mm/s, Then,, The time to “call for service”:, V = 0.08 + 0.005 t = 5.6, t = 1104 hr., The time to “immediate repair”:, V = 0.08 + 0.005 t = 10, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , t = 1984 hr., , 136 / 150
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Case (22):, During a predictive maintenance program of a 2000 RPM air blowing, unit, the following vibration levels was obtained, the stud fixed, vibrometer used has 0.7 damping ratio and 10 HZ natural frequency., Hours 100, mm/s 058, , 200, 1.08, , 300, 1.58, , 400, 2.08, , 500, 2.58, , 600, 3.08, , 700, 3.58, , 800, 4.08, , 900, 4.58, , Required:, 1. Find the percentage error in the measured vibration if the high, level corresponds to 25 HZ., 2. Construct the vibration trending and predict the vibration level, after 110 hours., 3. Does the above results changed if the vibrometer fixed by a waxy, material, why?, 4. Using the Canadian specification CDA/MS/NVSH107, predict, the time to “call for service” and to “immediate repair” starting, from the last measurement (at t1), , Solution:, 1- percentage error in the measured vibration level, measured frequency w = 25 [Hz]), Vibrometer natural frequency wn = 10 [Hz], Z= damping factor =0.7, w/wn= 25/10= 2.5, MF= (w/wn)^2/{[(1- (w/wn)^2)^2]+(2z w/wn)^2}0.5, MF=0.99, Percentage error (e%) =100(1-MF)=0.9%, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 137 / 150
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Construction of vibration trending:, By using least square method:, Time in hours =t, Vibration velocity in mm/s=v, n= number of the measured data =9, a &b are constants to be evaluated, a∑ti^2+b∑ti=∑ti*v, ∑vi =23.22, ∑ti=4500, a*2850000+b*4500=1460, a=0.005, , a ∑ti +bn= ∑vi, ∑ti^2=2850000, a*4500+9b=23.22, b=0.08, , v=0.08+0.005t [mm/s], Prediction of the vibration level after 110 hours, v=.08+.005*110=0.63 mm/s, 2- if the vibrometer fixed by a waxy material instead of stud, fixing:, the value of vibrometer natural frequency wn α k/m, for wax k, become smaller so the value w/wn become larger . i.e. the value w/wn, become more bigger i.e. this fixation will improve the measured, values (become more accurate) ., 3- from the Canadian specification CAD/MS/NVSH107 at 2000, rpm, the permissible vibration level to call for service =5.6 [mm/s], the permissible vibration level to call for immediate repair =10 [mm/s], The time to call for service :, 0.08+0.005t=5.6 t=1104 hours, The time to call for immediate reaper :, 0.08+0.005t=10 t=1984 hours, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 138 / 150
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Case (23):, The following Figure shows the line diagram of a pumping, system., , Motor, rev/min 1800, , Coupling, , Gearbox, Ratio 1:10, Gear 1, , B1, , B2, Gear 2, , Pump, B3, , B4, , Find the possible vibration frequencies for the following, machinery faults:, 1- Unbalance in motor and pump., 2- Misalignment of motor and gear shafts., 3- Bearing 3 outer race if it is a ball bearing having, (number of balls 10, ball diameter 5 mm, Pitch circle, diameter 50 mm, and Angle β= 0)., 4- Bearing 4 problems (journal bearing)., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 139 / 150
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1- Unbalance in motor and pump., Motor 1800 rpm, Gearbox Ratio 1:10, N1 = 1800, , N2=?, , Z1/Z2 = 10/1, , Speed ratio = N1 / N2 = Z1 / Z2, 1800/N2 = 10 / 1, , N2= 180 rpm, , From fault diagnosis table,, The frequency of vibration due to unbalance in motor, = 1 * rpm = 1800 rpm = 1800/60 = 30 Hz, The frequency of vibration due to unbalance in pump, = 1 * rpm = 180 rpm = 180/60 = 3 Hz, 2- Misalignment of motor and gear shafts., The frequency misalignment of motor:, = (1 to 2) * rpm = (1 to 2) * 1800 rpm, From (30 to 60) Hz, The frequency misalignment of gear shifts:, = (1 to 2) * rpm = (1 to 2) * 180 rpm, From (3 to 6) Hz, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 140 / 150
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3- Bearing 3 outer race:, if it is a ball bearing having, n = number of balls 10,, Bd = ball diameter 5 mm,, Pd = Pitch circle diameter 50 mm,, β= Angle =0., The frequency of vibration due to outer race defect:, = (n/2) (rpm/60) (1 – (Bd/Pd) cos β, = (10/2) (180/60) (1 – (5/50) cos 0, = 5 * 3 * 0.9 = 13.5 Hz, 4- Bearing 4 problems (journal bearing)., The frequency of vibration due to journal bearing loose, in housing:, = (1/2 to 1/3) rpm, rpm: rev/min of pump shaft = 180, The frequency of vibration due to journal bearing loose, in housing:, = (1/2 to 1/3) 180/60 = (1.5 to 1) Hz, Oil film whirl or whip in Journal bearings: Slightly less, than half shaft speed (42 to 48%), (0.42 to 0.48) 180/60 = (1.26 to 1.44) Hz, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 141 / 150
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Lubricating oil analysis, Oil analysis has become an important aid to preventive, maintenance. Laboratories recommend that samples of, machine lubricant be taken at scheduled intervals to, determine the condition of the lubricating film that is, critical to machine-train operation. Typically eleven tests, are conducted on lube oil samples:, 1- Viscosity : is one of the most important properties of, lubricating oil. The actual viscosity of oil samples is, compared to an unused sample to determine the, thinning of thickening of the sample during use., Excessively low viscosity will reduce the oil film strength,, weakening its ability to prevent metal-tometal locations, in the bearing support structure, reducing its ability to, lubricate., 2. Contamination : of oil by water or coolant can, cause major problems in a lubricating system. Many of, the additives now used in formulating lubricants contain, the same elements that are used in coolant additives., Therefore, the laboratory must have an accurate, analysis of new oil for comparison., 3. Fuel dilution : of oil in an engine weakens the oil, film strength, sealing ability, and detergency. Improper, operation, fuel system leaks, ignition problems,, improper timing, or other deficiencies may cause it. Fuel, dilution is considered excessive when it reaches a level, of 2.5 to 5 per cent., 4. Solids content : is a general test. All solid, materials in the oil are measured as a percentage of the, sample volume or weight. The presence of solids in a, lubricating system can significantly increase the wear on, Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 142 / 150
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lubricated parts. Any unexpected rise in reported solids, is cause for concern., 5. Fuel soot : is an important indicator for oil used, in diesel engines and is always present to some extent., A test to measure fuel soot in diesel engine oil is, important since it indicates the fuel burning efficiency of, the engine. Most tests for fuel soot are conducted by, infrared analysis., 6. Oxidation : of lubricating oil can result in lacquer, deposits, metal corrosion, or thickening of the oil. Most, lubricants contain oxidation inhibitors. However when, additives are used up, oxidation of the oil itself begins., The quantity of oxidation in an oil sample is measured, by differential infrared analysis., 7. Nitration : results from fuel combustion in, engines. The products formed are highly acidic and they, may leave deposits in combustion areas. Nitration will, accelerate oil oxidation. Infrared analysis is used to, detect and measure nitration products., 8. Total acid number : (TAN) is a measure of the, amount of acid or acid-like material in the oil sample., Because new oils contain additives that affect the TAN, number, it is important to compare used oil samples, with new, unused, oil of the same type. Regular analysis, at specific intervals is important to this evaluation., 9. Total base number : (TBN) indicates the ability, of an oil to neutralize acidity. The higher the TBN, the, greater is its ability to neutralize acidity. Typical causes, of low TBN include using the improper oil for an, application, waiting too long between oil changes,, overheating and using high sulfur fuel., Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 143 / 150
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10. Particle count : tests are important to anticipating, potential system or machine problems. This is especially, true in hydraulic systems. The particle count analysis, made a part of a normal lube oil analysis is quite, different from wear particle analysis. In this test, high, particle counts indicate that machinery may be wearing, abnormally or that failures may occur because of, temporarily or permanently blocked orifices. No attempt, is made to determine the wear patterns, size and other, factors that would identify the failure mode within the, machine., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 144 / 150
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11. Spectrographic analysis : allows accurate, rapid, measurements of many of the elements present in, lubricating oil. These elements are generally classified, as wear metals, contaminates, or additives. Some, elements can be listed in more than one of these, classifications. Standard lubricating oil analysis does not, attempt to determine the specific failure modes of, developing machine-train problems. Therefore,, additional techniques must be used as part of a, comprehensive predictive maintenance program., 12. Wear particle analysis : is related to oil, analysis only in that the particles to be studied are, collected through drawing a sample of lubricating oil., Where lubricating oil analysis determines the actual, condition of the oil sample, wear particle analysis, provides direct information about the wearing condition, of the machine-train. Particles in the lubricate of a, machine can provide significant information about the, condition of the machine. This information is derived, from the study of particle shape, composition, size and, quantity. Wear particle analysis is normally conducted in, two stages., The first method used for wear particle analysis is, routine monitoring and trending of the solids content of, machine lubricant. In simple terms the quantity,, composition and size of particulate matter in the, lubricating oil is indicative of the mechanical condition of, the machine. A normal machine will contain low levels of, solids with a size less than 10 microns. As the machine’s, condition degrades, the number and size of particulate, matter will increase., The second wear particle method involves analysis of, the particulate matter in each lubricating oil sample., Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 145 / 150
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Five basic types of wear can be identified according, to the classification of particles: rubbing wear, cutting, wear, rolling fatigue wear, combined rolling and sliding, wear and severe sliding wear. Only rubbing wear and, early rolling fatigue mechanisms generate particles, predominantly less than 15 microns in size., (a) Rubbing wear is the result of normal sliding, wear in a machine. During a normal break-in of a wear, surface, a unique layer is formed at the surface. As long, as this layer is stable, the surface wears normally. If the, layer is removed faster than it is generated, the wear, rate increases and the maximum particle size increases., Excessive quantities of contaminate in a lubrication, system can increase rubbing wear by more than an, order of magnitude without completely removing the, shear mixed layer. Although catastrophic failure is, unlikely, these machines can wear out rapidly., Impending trouble is indicated by a dramatic increase in, wear particles., (b) Cutting wear particles are generated, when one surface penetrates another. These particles, are produced when a misaligned or fractured hard, surface produces an edge that cuts into a softer surface,, or when abrasive contaminate become embedded in a, soft surface and cut an opposing surface. Cutting wear, particles are abnormal and are always worthy of, attention. If they are only a few micron long and a, fraction of a micron wide, the cause is probably a, contaminate. Increasing quantities of longer particles, signal a potentially imminent component failure., (c) Rolling fatigue is associated primarily with, rolling contact bearings and may produce three distinct, particle types: fatigue spall particles, spherical particles,, and laminar particles. Fatigue spall particles are the, Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 146 / 150
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actual material removed when a pit or spall opens up on, a bearing surface. An increase in the quantity or size of, these particles is the first indication of an abnormality., Rolling fatigue does not always generate spherical, particles and they may be generated by other sources., Their presence is important in that they are detectable, before any actual spalling occurs. Laminar particles are, very thin and are formed by the passage of a, wearparticle through a rolling contact. They, frequently have holes in them. Laminar particles may be, generated throughout the life of a bearing, but at the, onset of fatigue spalling the quantity increases., (d) Combined rolling and sliding wear, results from the moving contact of surfaces in gear, systems. These larger particles result from tensile, stresses on the gear surface, causing the fatigue cracks, to spread deeper into the gear tooth before pitting. Gear, fatigue cracks do not generate spheres. Scuffing of, gears is caused by too high a load or speed. The, excessive heat generated by this condition breaks down, the lubricating film and causes adhesion of the mating, gear teeth. As the wear surfaces become rougher, the, wear rate increases. Once started, scuffing usually, affects each gear tooth., (e) Severe sliding wear is caused by excessive, loads or heat in a gear system. Under these conditions,, large particles break away from the wear surfaces,, causing an increase in the wear rate. If the stresses, applied to the surface are increased further, a second, transition point is reached. The surface breaks down and, catastrophic wear ensures. Normal spectrographic, analysis is limited to particulate contamination with a, size of 10 microns or less. Larger contaminants are, ignored. This fact can limit the benefits that can be, derived from the technique., Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 147 / 150
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8- Optimal System Maintenance (OSM), OSM approaches focus on mathematical modeling and, developing optimal policies to inspect, repair, or replace, equipment based on its specific reliability characteristics., Generally, an OSM policy may be the one which either:, 1- Minimizes system maintenance cost rate;, 2- Maximizes the system reliability measures;, 3- Minimizes system maintenance cost rate while the system, reliability requirements are satisfied; or, 4- Maximizes the system reliability measures when the, requirements for the system maintenance cost are, satisfied., Mathematical Programming Approaches for Maintenance, Scheduling:, Network programming, Linear programming, Quadratic programming, Nonlinear programming, Stochastic programming, In maintenance scheduling, the objective function could be:, Minimizing maintenance cost, Minimizing workforce idle time,, Minimizing backlog, or, Maximizing resource utilization., Some important constraints are as follows:, Worker availability / Reliability, Equipment and tools availability, Spare parts availability, Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 148 / 150
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9- Risk Based Inspection (RBI), "Success is foreseeing failure" - Henry Petroski, RBI is a planning tool used to develop the optimum inspection, plans for critical equipment. Inspection is a crucial role in RBI., Components are essentially inspected for corrosion and other, damage at planned intervals, in order to identify corrective action, before failures actually occur., RBI refers to the application of risk analysis principles to manage, inspection programs for plant equipment., RBI refers to risk mitigation through inspection programs, using, risk analysis methodologies., RBI is a method using risk as a basis for prioritizing and managing, the efforts of an inspection program., RBI is an established technology for intelligently assigning, inspection activities to equipment which represents the highest risk, to a plant owner/operator. The result is an inspection plan based on, risk which satisfies both the regulatory and business requirements of, the client., RBI is a systematic tool that helps users make informed business, decisions regarding inspection and maintenance spending., RBI focuses on providing sufficient and appropriate inspection, resources for the high risk items, rather than over-inspecting lowrisk items "at the expense" of the higher risk areas., , , RBI studies define inspection programs. Information is generated, on the types of damage that may be expected, appropriate inspection, techniques to be used, where to look for the potential damage, and, how often inspections should take place., , RBI is regarded as a cost effective alternative to traditional, inspection., Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 149 / 150
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RBI is used for planning and implementation of inspection and, maintenance programs., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 150 / 150
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, , RBI studies define inspection programs. Information is generated, on the types of damage that may be expected, appropriate inspection, techniques to be used, where to look for the potential damage, and, how often inspections should take place., , , , The highest risk is mostly associated with a small percentage of, plant items. History tells us that 80% of the risk in industrial plants, in general is related to 20% of the pressure equipment. To be more, efficient with inspections and maintenance, it is useful to identify, this 20% higher risk assets., , RBI has been used in the nuclear power generation industry for, some time and is also employed in refineries and petrochemical, plant., RBI has been applied in industries such as power generation,, refineries, petrochemical plants and pipelines., , RBI Targets, The ultimate goals of RBI are:, To develop a cost-effective inspection and maintenance program, that provides assurance of acceptable mechanical integrity and, reliability., To improve plant HSE (Health, Safety and Environment), To improve plant reliability, availability and maintainability (RAM), To reduce maintenance down time cost, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 151 / 150
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10Reliability, (RCM), , Centered, , Maintenance, , RCM is a systematic approach to establish a good maintenance, program for critical equipment to improve the system availability and, reduce the maintenance cost, by focusing on the most important, functions of the system, and avoiding or removing maintenance actions, that are not strictly necessary., RCM involves the establishment or improvement of a maintenance, program in the most cost-effective and technically feasible manner. It, utilizes a systematic, structured approach that is based on the, consequences of failure. As such it represents a shift away from timebased maintenance tasks and emphasizes the functional importance of, system components and their failure/maintenance history., The concept of RCM finds its roots in the early 1960's, with RCM, strategies for commercial aircraft developed in the late 1960s, when, wide-body jets were introduced to commercial airline service. A major, concern of airlines was that existing time-based preventive maintenance, programs would threaten the economic viability of larger, more, complex aircraft. The experience of airlines with the RCM approach, was that maintenance costs remained roughly constant but that the, availability and reliability of their planes improved. RCM is now, standard practice for most of the world's airlines., There are four features that define & characterize RCM, which are as, follows:, Preserve function, by addressing system function, inputs &, outputs., Identify failure modes that can defeat the function., Prioritize function need (via the function mode)., Select only applicable & effective PM tasks, RCM concept was developed in the early 1970s by the Commercial, Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 152 / 150
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Airline Industry Maintenance Steering Group., RCM is a process used to determine the maintenance requirements, of any physical asset in its operating context., In many RCM applications the plant already has effective, maintenance programs., The RCM projects therefore be an upgrade projects, identify and, select the most effective PM tasks, to recommend new tasks or, revisions , and to eliminate ineffective tasks then apply this changes, within the existing programs in a way that will allow the most, efficient allocation of resources., Benefits of R.C.M, • Improve operating performance., • Improve quality, • Greater maintenance cost effectiveness, • Increase equipment life, • Better teamwork, • Increase moral, , RCM is based upon two criteria:, 1- Non-safety-critical components:, Scheduled Maintenance (SM) tasks should be carried out, only when performance of the scheduled task will reduce the, life-cycle cost of ownership., , 2- Safety-critical components:, SM tasks must be performed only when such tasks will, prevent a decrease in reliability and/or deterioration of, safety to unacceptable levels or when the tasks will reduce, the life-cycle cost of ownership., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 153 / 150
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RCM Steps:, 1. System selection and information analysis., 2. System boundary definition., 3. System description and functional block diagram., 4. System function and functional failures., 5. Failure mode and effects analysis., 6. Logic (decision) tree analysis., 7. Task selection., RCM Implementation Steps, 1. RCM Feasibility Study, 2. RCM Team Building & Training, 3. RCM Master Plan (1-3 years), 4. Design of Maintenance Performance Evaluation System, 5. Design of Maintenance Criticality System, 6. System Selection & Information Analysis, 7. System Description & Process Analysis, 8. Equipment Classification (critical & non-critical), 9. Maintenance Information Analysis, 10. Failure Mode & Effect Analysis (FMEA), 11. Risk Analysis, 12. Logic (Decision) Tree Analysis, 13. Task Selection and Job Plan, 14. Maintenance Program & Planning, 15. Implementation, 16. RCM Performance Evaluation, 17. Corrective Actions, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 154 / 150
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Failure Modes and Effects Analysis (FMEA), A “Hazard Identification” method, Involves breaking a system down into sub-systems and, component parts, The systematic discipline involves scrutinizing each component, – How might a component fail (failure modes)?, – What are the consequences of each failure mode and, combinations of failure modes?, – What environmental factors affect failure modes?, Interventions are developed to improve total system reliability, Equipment, ID # Description, , Failure Failure, mode Cause, , Failure Effects, Local, , System, , Unit, , Failure Modes: the manner in which a fault occur, the way in which, the element fail., Failure Effects: what would happen if the failure mode occurs, (efficiency, cost and time)., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 155 / 150
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TOTAL PRODUCTIVE MAINTENANCE (TPM), TPM is an integrated approach for maintenance management to, maximize equipment effectiveness by establishing a comprehensive, productive-maintenance system., TPM was defined by Japanese Institute of Plant Engineers (JIPE) in, 1971., TPM has a positive and significant relationship with lower costs,, higher levels of quality, and stronger delivery performance. Hence,, TPM has a strong positive impact on improving productivity., TPM is an integrated approach for maintenance management to, maximize equipment effectiveness by establishing a comprehensive, productive-maintenance system., TPM involves operational and maintenance staff working together as a, team to reduce wastage, minimize downtime and improve end-product, quality [Tsang, 2000 and Eti et al., 2004]., McKone and Weiss (1998) identify significant gaps between industry, practice and academic research and emphasized the need to bridge, these gaps by providing guidelines for implementing TPM activities., TPM is an approach to continuously improve the performance of, certain industrial activities, and in the first place of maintenance. To, achieve an overall workshop improvement, TPM strives for the, development of optimal human–machine conditions [Waeyenbergh and, Pintelon, 2002]., TPM is a proven and successful procedure for introducing maintenance, considerations into organizational activities. It involves operational and, maintenance staff working together as a team to reduce wastage,, minimize downtime and improve end-product quality., TPM builds on the concepts of JIT, TQM and design to achieve, minimum life-cycle cost (LCC) [Eti et al., 2004]. TPM aims to obtain, the maximum production output with the best levels of product quality,, Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 156 / 150
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and doing this at minimum cost to the facility providing the least risk, of breakdown [O’Donoghue and Prendergast, 2004]., TPM provides a comprehensive company-wide approach to, maintenance management, which can be divided into long-term and, short-term activities. In the long-term, efforts focus on new equipment, design and elimination of sources of lost equipment time and typically, require the involvement of many areas of the organization. In the shortterm, attention is focused on an autonomous maintenance program for, the production department, a planned maintenance program for the, maintenance department, and skill development for operations and, maintenance personnel. Most of the previous studies focused on the, short-term maintenance efforts [McKone et al., 1999 and 2001]., The TPM bundle includes practices primarily designed to maximize, equipment effectiveness through planned preventive-predictive, maintenance of the equipment and using maintenance optimization, techniques. More generally, emphasis on maintenance may also be, reflected by the emphasis given to new process equipment or, technology acquisition [Cua et al., 2001]., The impact of TPM on improving productivity has been stated in many, studies, and there is a lot of excellent case studies, for example; a semiautomated assembly cell [Chand and Shirvani, 2000]; large Global, companies [Ireland and Dale, 2001]; pulp and paper [Van-der-Wal and, Lynn, 2002]; Ceramics [Ferrari et al., 2002]; and electronics [Chan et, al., 2003]., Refer to Gomaa, 2005, TPM benefits may be concluded as follows: (1), Improvement in OEE (25 to 50%); (2) Improvement in labor, productivity (30 to 40%); (3) Reduction in product defects (25 to, 30%); (4) Reduction in maintenance cost (10 to 30%); (5) Reduction in, unplanned maintenance (20 to 50%); (6) Reduction in manufacturing, cost (5 to 15%); and hence; (7) Improvement in total system, productivity (20 to 30%); (8) Promotion of team approach; (9) Improve, operator satisfaction; (10) Empowerment of manpower; and hence (11), Reduce the communication problem., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 157 / 150
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TPM model is based on five pillars: (1) Individual equipment, improvements to eliminate the equipment losses; (2) Autonomous, maintenance; (3) Planned PM; (4) Maintenance/operations skills, training; and (5) Maintenance plan design and early equipment, management [Waeyenbergh and Pintelon, 2002]., TPM main objectives are to achieve zero breakdowns and zero defects, through: (1) increasing operator involvement and ownership of the, process; (2) improving problem-solving by the team; (3) refining, preventive and predictive maintenance activities; (4) focusing on, reliability and maintainability engineering; and (5) upgrading each, operator's skills [Eti et al., 2004]., Refer to Gomaa, 2005, TPM implementation activities may be, concluded as follows:, 1. System selection and information analysis;, 2. Master plan for production and maintenance management;, 3. Autonomous maintenance programs for the production, department;, 4. Planned maintenance programs for the maintenance department;, 5. Equipment design modifications for maintenance department or, suppliers;, 6. Manpower education and training;, 7. Manpower motivation and direction; and, 8. Performance evaluation and continuous improvement., Chan et al. (2003) developed a TPM program in four phases, which are, as follows: introduction-preparatory stage, introduction stage of TPM, implementation, introduction-execution stage of TPM implementation,, and finally, establishment stage., Reviewing the literature, TPM procedures may be concluded in five, phases; the following are the major activities in each phase, [Gomaa, 2005]:, 1. Phase 1. TPM feasibility study: This phase focuses on the cost, benefits analysis and decision making processes;, Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 158 / 150
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2. Phase 2. Problem identification and developing equipment, awareness: It includes study the organization, analyze the existing, maintenance problems, analyze the working conditions, start the, equipment awareness program, and identify the critical machine, and components., 3. Phase 3. TPM procedure development: This phase deals with, collect all information on machines, development standard, servicing procedures, development proper operator, communication channels, development continuous feedback for, operator response, development quality consciousness among, operators, develop self-maintenance procedures, develop data, collection procedures, develop training materials, and develop, quality feedback system., 4. Phase 4. Initial implementation program: It focuses on customize, the servicing procedure for the specific machine, conduct, training, implement procedures and policies, problem solving, through problem solving techniques, and feedback from operators, and audits., 5. Phase 5. TPM Program Maintenance and stabilization: This phase, deals with develop the structure and policies for the TPM steering, committee, develop information flow, develop guidelines for, maintenance scheduling, conduct advanced training, develop, guidelines for machine trend reports and improvements, develop, procedures for document control, feedback and improvement,, and company-wide TPM implementation program., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 159 / 150
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System, configuration, , Maintenance, planning &, control, , Production, planning &, control, , Total Productive Maintenance, Manpower, training &, motivation, , Product/service, quality control, , Spare parts, planning &, control, , . Max, OEE, , TPM Master, plan, , Top & control, management, , Operational management, )departments & workshops(, , Figure - Proposed TPMIS Outline., , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 160 / 150
Page 161 : Main References:, 1. Jones, R.B. “ Risk-Based Management ”, Gulf Publishing, Company, Houston, 1995., 2. Moubray, Jhon. “ Reliability Centered Maintenance II ”,, Industrial Press Inc. New York, 1991., 3. Parra, Carlos, “Course of Reliability- Centered, Maintenance”, Universidad de los Andes, Mérida Venezuela, 1998., 4. Smith, Anthony. “ Reliability Centered Maintenance ”,, McGraw Hill Inc., New York, 1992., , For more information:, Dr. Attia H. Gomaa,
[email protected], Mobile: 0122738497, , Fundamentals Maintenance Management, Dr. Attia H. Gomaa, , 161 / 150
