Operations Management (OPM530) C11 Maintenance

Prepared by: Shatina Saad @ FPP OPM 53311-1

Operations Operations ManagementManagement

Maintenance and ReliabilityMaintenance and ReliabilityChapter 11Chapter 11


OutlineOutline 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


Learning ObjectivesLearning ObjectivesWhen 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 performance


All activities involved in keeping a system’s equipment working

Objective: Maintain system capability & minimize total costs

© 1995 Corel Corp.

Maintenance ManagementMaintenance Management


The Strategic Importance of The Strategic Importance of Maintenance and ReliabilityMaintenance and Reliability

Failure has far reaching effects on a firm’s operation reputation profitability customers product employees profits


Maintenance Procedures

Employee Involvement

Maintenance PerformanceMaintenance Performance

© 1995 Corel Corp.

© 1995 Corel Corp.

Maintenance PerformanceMaintenance Performance


Good Maintenance & Reliability Good Maintenance & Reliability StrategyStrategy

Requires: Employee involvement Maintenance and reliability procedures

To yield: Reduced inventory Improved quality Improved capacity Reputation for quality Continuous improvement


Employee InvolvementEmployee Involvement

Information sharing Skill training Reward system Power sharing

© 1995 Corel Corp.


Maintenance & Reliability Maintenance & Reliability ProceduresProcedures

Clean and lubricate Monitor and adjust Minor repair Computerized

records

Maintenance Procedures

© 1995 Corel Corp.


Lower operating

costs

Continuous improvement

Faster, more dependable throughput

Higher productivity

Improved quality

Improved capacity

Reduced inventory

Maintenance

Maintenance BenefitsMaintenance Benefits


Tactics forTactics for Reliability and Maintenance Reliability and Maintenance

Reliability Tactics improving individual components providing redundancy

Maintenance Tactics implementing preventive maintenance increasing repair capabilities


System Reliability -System Reliability - Components in Series Components in Series

Average Reliability of all Components (Percent)

Relia

bility

of t

he S

yste

m (P

erce

nt)

100

80

60

40

20

0

100 99 98 97 96

n=1

n=10

n=50

n=100

n=200

n=300n=400


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

Evaluating MaintenanceEvaluating Maintenance


Failure Rate Failure Rate

Number of failuresFR (%) = * 100% Number of units tested

FR (N) = Number of Failures

Number of unit-hours of operating time


Lifetime Failure RatesLifetime Failure Rates

Infantmortality

andimproper use

failure

“normal” failure Wearoutfailure

Failurerate

Lifetime


Providing RedundancyProviding Redundancy

Probability of first

component working

Probability of second component working

+

Probability of needing second component

* = P(R)


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

Maintenance DecisionsMaintenance Decisions


Preventive Breakdown

Routine inspection & servicing

Prevents failures Bases for doing

Time: Every day Usage: Every 300 pieces Inspection: Control chart

deviations

Non-routine inspection & servicing

Remedial Basis for doing

Equipment failure

Types of MaintenanceTypes of Maintenance


Mean Time Between Failure and Mean Time Between Failure and Preventive MaintenancePreventive Maintenance

Frequencyof failure

Mean Time Between Failure

Candidate for preventivemaintenance will have

distribution with lowvariability


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

Organizing theOrganizing the Maintenance Function Maintenance Function


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

Operator-Ownership ApproachOperator-Ownership Approach


A Computerized Maintenance SystemA Computerized Maintenance System


Maintenance Commitment

Cost

Preventive Maintenance CostTotTotal Maintenance Cost

Breakdown Cost

Optimal

Maintenance CostsMaintenance CostsTraditional ViewTraditional View


Maintenance CostsMaintenance CostsFull Cost ViewFull Cost View

Maintenance Commitment

Cost

Optimal

Total costs

Full cost of breakdowns

Preventive maintenance costs


Contract for Preventive Contract for Preventive MaintenanceMaintenance

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


Increasing Repair Capabilities:Features Increasing Repair Capabilities:Features of A Good Maintenance Facilityof 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


Operations Manager Must Determine Operations Manager Must Determine How Maintenance Will be PerformedHow Maintenance Will be Performed

Operator Maintenance Department

Manufacturer’s field service

Depot Service (return equipment)

Competence is higher as we more to the right

Preventive maintenance costs less and is faster as we move to the left


Total Productive Maintenance Total Productive Maintenance (TPM)(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


A Key To SuccessA 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 Techniques for Establishing Maintenance PoliciesMaintenance 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

Operations Management (OPM530) C11 Maintenance

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