Operations Management (opm530) C11 Maintenance

Operations Management Maintenance and Reliability Chapter 11 Prepared by: Shatina Saad @

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Outline ♦ THE STRATEGIC IMPORTANCE OF MAINTENANCE AND RELIABILITY ♦ RELIABILITY Improving Individual Components ♦ Providing Redundancy ♦

♦ MAINTENANCE ♦ ♦

Implementing Preventive Maintenance Increasing Repair Capability

♦ TOTAL PRODUCTIVE MAINTENANCE ♦ TECHNIQUES FOR ESTABLISHING MAINTENANCE POLICIES Prepared by: Shatina Saad @

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Learning Objectives When you complete this chapter, you should be able to : Identify or Define: ♦ Maintenance ♦ Mean time between failures ♦ Redundancy ♦ Preventive maintenance ♦ Breakdown maintenance ♦ Infant mortality Describe or Explain: ♦ How to measure system reliability ♦ How to improve maintenance ♦ How to evaluate maintenance OPM 533 Prepared by: Shatina Saad @ FPP 11-3 performance

Maintenance Management ♦ All activities involved in keeping a system’s equipment working ♦ Objective: Maintain system capability & minimize total costs

© 1995 Corel Corp.

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The Strategic Importance of Maintenance and Reliability

♦ Failure has far reaching effects on a firm’s ♦

operation ♦ reputation ♦ profitability ♦ customers ♦ product ♦ employees ♦ profits Prepared by: Shatina Saad @

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Maintenance Performance

Employee Involvemen t

Maintenanc e Procedures

Maintenance Performance

© 1995 Corel Corp.

© 1995 Corel Corp.

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Good Maintenance & Reliability Strategy ♦ Requires: ♦

Employee involvement ♦ Maintenance and reliability procedures

♦ To yield: ♦

Reduced inventory ♦ Improved quality ♦ Improved capacity ♦ Reputation for quality ♦ Continuous improvement Prepared by: Shatina Saad @

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Employee Involvement ♦ Information sharing ♦ Skill training ♦ Reward system ♦ Power sharing © 1995 Corel Corp.

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Maintenance & Reliability Procedures ♦ Clean and lubricate ♦ Monitor and adjust ♦ Minor repair ♦ Computerized records

Maintenanc e Procedures

© 1995 Corel Corp.

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Maintenance Benefits Lower operating costs

Reduced inventory

Maintenance

Improved capacity

Continuous improvement Prepared by: Shatina Saad @

Faster, more dependable throughput

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Higher productivity

Improved quality 11-10

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Tactics for Reliability and Maintenance ♦ Reliability Tactics ♦ ♦

improving individual components providing redundancy

♦ Maintenance Tactics ♦ ♦

implementing preventive maintenance increasing repair capabilities

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Reliability of the System (Percent)

System Reliability Components in Series

100

100 n=1 80

n=10

60

n=

50

40

n= 20 0

n=

40 0

10 0

n=

30 0

n=20 0

99 98 97 Average Reliability of all Components (Percent) Prepared by: Shatina Saad @

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Evaluating Maintenance

♦ Reliability ♦

Probability that an item will function for a given time

♦

Reliability of Components in Series

R = R1 * R2 * R3 * ... ♦ Mean time between failures (MTBF) ♦

Average time between failures of a repairable item MTBF = 1 / Failure Rate (N)

♦ Failure rate ♦

Reciprocal of MTBF

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Failure Rate Number of failures

FR (%) = * 100%

Number of units tested

FR (N) =

Number of Failures

Number of unit-hours of operating time

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Lifetime Failure Rates “normal” failure

Failure rate

Wearout failure

Infant mortality and improper use failure

Lifetime Prepared by: Shatina Saad @

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Providing Redundancy

Probabilit y of first compone + nt working

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Probability of second componen * t working

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Probabili ty of needing second compone nt

= P(R)

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Maintenance Decisions ♦ How much preventive & breakdown maintenance ♦ Who performs maintenance ♦ ♦

Centralized, decentralized, operator etc. Contract or in-house

♦ When to replace or repair ♦ How much to replace ♦

Individual or group replacement

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Types of Maintenance Preventive

Breakdown

♦ Routine inspection & servicing ♦ Prevents failures ♦ Bases for doing ♦ Time: Every day ♦ Usage: Every 300

♦ Non-routine inspection & servicing ♦ Remedial ♦ Basis for doing ♦ Equipment failure

pieces ♦ Inspection: Control chart deviations Prepared by: Shatina Saad @

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Mean Time Between Failure and Preventive Maintenance Candidate for preventive maintenance will have distribution with low variability

Frequency of failure

Mean Time Between Failure Prepared by: Shatina Saad @

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Organizing the Maintenance Function ♦ Centralized maintenance department ♦

Does all maintenance (PM & breakdown)

♦ Decentralized maintenance department ♦

Useful if different equipment used in different areas of company

♦ Contract maintenance ♦

Used if little equipment or expertise

♦ Operator ownership approach Prepared by: Shatina Saad @

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Operator-Ownership Approach ♦ Operator does preventive maintenance ♦ ♦ ♦ ♦

Equipment condition is their responsibility Learns equipment better Increases worker’s pride Reduces repair time & PM costs

♦ Maintenance department is backup ♦ ♦ ♦

Handles non-routine problems Provides maintenance training Has plant-wide responsibilities

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A Computerized Maintenance System

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Maintenance Costs Traditional View Cost

e

nc a n e

nt i a lM a t To

t s o C

st o C ce n a en t n i a M e iv t n e Prev Breakdown Cost

Maintenance Commitment

Optimal Prepared by: Shatina Saad @

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Maintenance Costs Full Cost View Cost Total costs Full cost of breakdowns Preventive maintenance costs Optimal Maintenance Commitment Prepared by: Shatina Saad @

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Contract for Preventive Maintenance ♦ Compute the expected number of breakdowns without the service contract ♦ Compute the expected breakdown cost per month with no preventive maintenance contract ♦ Compute the cost of preventive maintenance ♦ Compare the two options Prepared by: Shatina Saad @

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Increasing Repair Capabilities:Features of A Good Maintenance Facility ♦ Well-trained personnel ♦ Adequate resources ♦ Ability to establish a repair plan and priorities ♦ Ability and authority to do material planning ♦ Ability to identify the cause of breakdowns ♦ Ability to design ways to extend MTBF Prepared by: Shatina Saad @

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Determine How Maintenance Will be Performed Operator Maintena Manufactu Depot Service nce rer’s field (return Departm service equipment) ent

Competence is higher as we more to the right

Preventive maintenance costs less and is faster as we move to the left Prepared by: Shatina Saad @

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Total Productive Maintenance (TPM)

♦ Additional requirements of: ♦

Designing machines that are reliable, easy to operate and easy to maintain ♦ Emphasizing total cost of ownership when purchasing machines, so that service and maintenance are included in the cost ♦ Developing preventive maintenance plans that utilize the best practices of operators, maintenance departments, and depot services ♦ Training workers to operate and maintain their own machines Prepared by: Shatina Saad @

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A Key To Success ♦ High utilization of facilities, tight scheduling, low inventory and consistent quality demand reliability - total preventive maintenance is the key to reliability.

Techniques for Establishing Maintenance Policies ♦ Simulation - enables one to evaluate the impact of various maintenance policies ♦ Expert systems - can be used by staff to help diagnose faults in machinery and equipment Prepared by: Shatina Saad @

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