Equipment Efficiency: Availability, performance and maintenance

1
Equipment EfficiencyAvailability,
performanceand maintenance

• Operations Analysis and Improvement
• 2009 Spring
• Dr. Tai-Yue Wang
• Industrial and Information Management Department
• National Cheng Kung University

2
Presentation

• The role of maintenance is to insure the
  survivability and proper functioning of all
  company hardware.
• Most maintenance departments are considered a
  necessary evil.
• Investments required to improve production
  processes usually take on a low priority.

3
Presentation

• Maintenance evolution, as well as maintenance
  technique evolution, has developed in parallel
  for many companies.
• Remediate hardware failures.
• Prevent future problems with the equipment.
• Incorporate basic maintenance tasks into their
  daily production routine.
• Predicting equipment breakdowns.

4
Introduction

• Maintenances primary objective is to maintain,
  at a high operative level, the productive
  resources in order to assure their service at an
  expected cost.
• Maintenance is the machines medicine.
• Determine the right moment to replace the
  equipment.
• It may be better to simply unplug it.

5
Introduction

• Elements that need maintenance.
• Machines and tools.
• Facilities (compressed air, heating,)
• Buildings (walls, illumination,)
• Information and transportation systems.

6
Introduction

• Some companies subcontract maintenance.
• Is contemplated in both the Just-in-time and the
  20 keys (key number 9) for lean.
• Improves the availability and performance rates
  of the equipment.

7
Types of maintenance

• Corrective -gt All industrial equipment is exposed
  to transitory (wear) or definitive breakdowns
  (catastrophic failure).
• Affecting its functionality and performance.
• Can represent high costs for enterprises.
• Preventive -gt The maintenance mission cannot only
  be repairing the breakdowns.
• They should be able to get ahead of the
  breakdowns.

8
Types of maintenance

• The preventive maintenance has two variants.
• Systematic preventive maintenance.
• Conditional preventive maintenance or predictive
  maintenance.

9
Corrective maintenance

• Also called breakdown maintenance.
• Up to the 1950s it was virtually the only
  maintenance.
• Machine stoppages hardly affected productive
  time.
• Repairs were carried out in an effective way.

10
Types of corrective maintenance

• Urgent repairs.
• Reestablishing the equipment into service.
• Repair is carried out is provisionally.
• The remainder of the tasks will/can be scheduled
  for a future time.

11
Types of corrective maintenance

• Scheduled corrective.
• Appears as a result of urgent repairs.
• Determine an appropriate time to repair the
  machine completely.
• After repairing the damaged component
• As good as new.
• At least as it was before.

12
Repair problems

• Repair tasks are performed quickly and under
  pressure, which can cause future problems.
• Repair time can be very high because replacement
  part(s) may have to be ordered from a supplier.

13
Repair problems

• Accidents can take place because of poor
  maintenance safety measures.
• Corrective maintenance policy implies higher
  labor costs.
• This policy can be justified in some cases.
• Equipment with a frequent replacement policy.
• Like personal office computers.
• When breakdown costs are small.
• Light bulbs fail.

14
Systematic preventive maintenance

• 1960s -gt the General Electric Corporation
  systematized a new type of maintenance called
  planned maintenance.

15
Systematic preventive maintenance

• Planned maintenance arrived to Japan.
• The bases of this systematic preventive
  maintenance process were established.
• Systematic substitution of some machine
  components.

16
Systematic preventive maintenance

• Applied to general wear or use components.
• Know with precision the components performance
  characteristics.

17
Systematic preventive maintenance

• Replacement policy might call for a component to
  be replaced every week or in other ways such as,
  every 300 working hours or every 1000 parts
  produced.

18
Conditional preventive maintenance

• Also called predictive maintenance.
• Systematic preventive maintenance can become very
  expensive.

19
Conditional preventive maintenance

• Conditional preventive maintenance is used to
  change components depending on their current
  state.
• The useful life for costly components can be
  extended.
• This type of maintenance best fits components
  where performance can be monitored.

20
Conditional preventive maintenance

• ISO 14000 (environmental norm) requires that
  industry avoid systematic preventive maintenance
  when working with environmentally harmful
  products.

21
Conditional preventive maintenance

• Predictive maintenance.
• Look for correlations between multiple parameters
  and the degradation of a component.
• Temperature (thermocouples),
• Noises (phonometer).
• Cracks (X-rays machine).
• Pressure losses (manometer).
• QS9000 recommends predictive maintenance.

22
Maintenance program implementation

• Almost all machines follow a similar lifecycle.
• Hidden small defects.
• Difficult to detect and to observe -gt It does not
  interfere with functionality.
• Increase of friction in an axle.
• Apparent small defects.
• Are more noticeable -gt They are normally not
  repaired.
• Small vibrations on a machine.

23
Maintenance program implementation

• Execution under expectations.
• The defects affect the equipment productivity.
• the standards of quality will be violated.

24
Maintenance program implementation

• Almost all machines follow a similar lifecycle.
• Intermittent stops.
• The machine intermittently produces defect parts.
• Small repairs are performed.
• Stops and breakdowns.
• Breakdowns are frequent.
• Production equipment may not be as new as we
  would like them to be.
• Stops and breakdown stage.

25
Maintenance program implementation

• Production equipment typically becomes more
  sophisticated/complex.
• More expensive every year.
• It has greater economic impact.
• Repairs should be done at a faster rate.
• Working shifts can also represent an obstacle for
  maintenance interventions.
• Limits possible maintenance tasks and scheduling.

26
Maintenance program implementation

• The objective of maintenance is to efficiently
  oversee equipment throughout the equipment life
  cycle.
• Cover the entire lifecycle
• Implementing an effective corrective maintenance.
• Preventive maintenance tasks.
• Implementing predictive maintenance strategies.

27
Getting started

• Become familiar with the resources that will
  require maintenance.
• Each maintained resource should be coded
  (resource id).
• Code the types of breakdowns and maintenance
  tasks.
• In a historical data study -gt Group failure
  causes.

28
Getting started

• Maintenance should have the following two
  documents.
• Facility Inventory.
• Lists all equipments and their principle
  characteristics.
• Code, record number, equipment type,
• Equipment History Files.
• Data given by the equipment manufacturer.
• Information about the location in the plant.
• Types of spare parts needed.

29
Corrective maintenance implementation

• Organize, in an effective way, the corrective
  maintenance procedures and actions.
• Breakdown occurs -gt Fill out a breakdown work
  order.
• If the worker can solve it -gt fill a report.
• If not -gt the work order will be sent to the
  maintenance department.
• Work request order will be issued.
• Maintenance workers will either repair the
  machine immediately or will schedule the repair.
• The repair can be provisional or definitive.

30
Scheduled corrective maintenance

• Variability in the corrective maintenance tasks
  duration can be problematic.
• Corrective orders and flow diagrams for
  repetitive repairs must be developed.
• Materials and spare parts that should be
  utilized.
• Maintenance workers tasks do not end with the
  equipment repair.
• They should gather all the breakdown information.
• Describe the process that was performed.

31
Scheduled corrective maintenance

• Each machine should have its own file with
  breakdown records.
• Analyze breakdown causes.
• Anticipate future problems.
• This file must be upgraded with each maintenance
  intervention.

32
Scheduled corrective maintenance

• Corrective maintenance tasks do not only consist
  on changing the broken or malfunctioning
  components.
• Study the causes and the frequency of the
  breakdowns.

33
Preventive maintenance implementation

• Avoid a breakdown of any resource, while keeping
  maintenance cost as low as possible.
• Two types of actions.
• Inspections.
• Observe and detect possible anomalies.
• Frequent checkups that follow a specific
  inspection plan.
• Revisions.
• Scheduled equipment stops.
• Systematic substitution of several machine
  components.
• Carried out during the weekend.

34
Preventive maintenance implementation

• Preventive maintenance tasks scheduling is
  mandatory in the ISO norms.

35
Preventive maintenance implementation

• These tasks can be planned daily, weekly, monthly
  or even annually.
• Scheduled at times when they do not affect the
  factorys production plan.
• Daily working problems force us to continuously
  reschedule these tasks.

36
Preventive maintenance implementation

• Equipment preventive maintenance tasks are also
  called PM orders.
• Each PM order should be based on a study of the
  equipment breakdown causes.
• FMEA tool described at the tools section.

37
Autonomous maintenance

• PM orders carried out by the production workers.
• Known as user maintenance orders.
• They should be simple and graphically
  represented.
• Many inspection tasks should be carried out every
  day.

38
Autonomous maintenance

• Significant amount of notices that could be
  easily handled by the production worker.
• It takes more time to fill out the request order
  than to fix the problem

39
Autonomous maintenance

• Autonomous maintenance includes these small tasks
  and three daily preventive measures.
• Cleaning, lubricating and checking.

40
Autonomous maintenance. Safety

• Safety is one of the most important restrictions.
• Autonomous tasks apply only for simple repair
  operations.
• Repair or maintenance should never be performed
  if the knowledge required to fix the machine is
  high.

41
Autonomous maintenance. Safety

• It can be very challenging to convince production
  workers about the importance of maintenance
  tasks.
• They do not consider their responsibility.

42
Autonomous maintenance

• Autonomous maintenance implementation process has
  a specific methodology.

43
TPM - Total Productive Maintenance

• In the 1970s, Nakajima developed in Japan TPM.
• New maintenance management philosophy.
• English translation was not published until 1988.
• JIPM Japanese Institute of Plants Maintenance.
• Grants the PM prize to the TPM top excellent
  companies.
• 60 of the winning companies during the first 17
  years are now part of the Toyota Group or
  suppliers of this Group.

44
TPM - Total Productive Maintenance

• Nakajima combined preventive maintenance theories
  with the total quality concept.
• Nakajima developed the Overall Equipment
  Efficiency ratio.

45
TPM keys

• Maximize the Overall Equipment Efficiency.
• Eliminating the six big losses.
• Autonomous maintenance implementation.
• In order to terminate the I operate, you repair
  mind set.
• Preventive engineering.
• Improving the equipments maintainability.

46
TPM keys

• Training workers for maintenance improvements.
• Propose methods for increasing the equipment
  availability.
• Initial equipment management.
• The objective of the TPM -gt Zero Breakdowns.
• Utilize tools such as the P-M analysis -gt
  Explained in tools section.

47
RCM - Reliability Centered Maintenance

• RCM was created in the United States in the
  1960s, to optimize the reliability of
  aeronautical equipment.
• RCM was not utilized in nuclear power stations
  until the 1980s.
• Recently has been implemented in the industrial
  world.

48
RCM - Reliability Centered Maintenance

• Needs a complete maintenance and breakdown record
  for each item of equipment.
• RCM objective is to determine the maintenance
  tasks that are more effective for the critical
  components.
• FMEA, reliability analysis, statistical
  techniques.
• It is necessary to have a preventive maintenance
  program implemented and running properly.

49
FMEA for equipment

• All defects have a root cause, and to eliminate
  future defects an action must be carried out.
• Defect -gt Gap between two elements
• Cause -gt Lack of lubrication or a loose fastener.
• Action -gt Grease or tighten the lose element.

50
FMEA for equipment

• To determine a good preventive maintenance plan,
  all the possible breakdowns, their causes and
  their corrective actions must be analyzed.
• The main tool to carry out this type of analysis
  is the FMEA for equipment (Failure Mode and
  Effects Analysis).
• Is a guide to analyze, in an organized manner,
  causes of possible equipment breakdowns.
• A group of workers is gathered to study the
  problems and failures

51
FMEA for equipment
52
FMEA for equipment

• Equipment functions.
• The functions that the equipment carries out.
• Provides compressed air during specific
  conditions.
• Failure modes.
• All the possible ways that the equipment can be
  forced to stop.
• Breaks, blockage, leaks, etc.

53
FMEA for equipment

• Failure effects.
• All possible consequences of each failure are
  analyzed in detail.
• Severity (S).
• 1 being not very serious.
• 4 very serious.

54
FMEA for equipment

• Failure causes.
• The origin of the failure is analyzed.
• Identify the anomaly that can lead to the
  failure.
• Probability (P).
• 1 not very frequent.
• 4 very frequent.

55
FMEA for equipment

• Actual controls.
• If, at the present time, some kind of control is
  carried out.
• Detection (D)
• 1 if the control does not always detect the cause
• 4 if it always detects.

56
FMEA for equipment

• After the first part of the FMEA table has been
  completed, the Risk Priority Number (RPN) is
  calculated.
• The product of the three quantified variables (S,
  P and D).
• Ranking failures by RPN.
• Analyze the causes that do not represent any
  threat.
• Special attention must be paid to those effects
  that have been considered critical.

57
FMEA for equipment

• The chosen plan of action and the employee
  responsible for carrying out this plan are
  registered in the same table utilized in the
  FMEA.
• After a FMEA application arises, the necessity of
  developing a preventive maintenance plan is
  recommended.

58
FMEA for equipment

• Preventive maintenance intervention periods (T).
• Know the component damage/wear behavior curve.
• Breakdowns and the time when the breakdowns
  occurred -gt Mean Time Between Failures (MTBF).
• T is based on the corrective percentage that the
  company would like to support (K).

59
Reliability

• Reliability is defined as the probability that an
  equipment will work satisfactorily, during a
  certain period of time under some specific
  working conditions.
• Reliability is a probability.
• Relative frequency of breakdowns.

60
Reliability

• All production equipment should work
  satisfactorily.
• Failure can be triggered by an abrupt change in
  the component characteristic or by progressive
  damage.
• Work satisfactorily for a specific period of
  time.
• Maintain quality standards during a reasonable
  period of time.
• RELIABILITY QUALITY TIME

61
Reliability

• The component life or equipment life duration
  depends on working conditions.
• Environmental (temperature or humidity).
• Operational (continuous starts and stops,
  electrical strain).

62
Reliability

• The system state depends on the primary group of
  elements that makes it work properly.
• Each element has a random lifetime.
• Estimate the lifetime of the components.
• Reliability -gt MBTF (Mean Time Between Failure)

63
Reliability and Maintainability

• Maintainability -gt probability that it must be
  repaired in a predetermined time following a
  specific repair procedure.

64
Reliability and Maintainability

• Maintainability depends on different factors.
• Machine factors.
• Accessibility or interchangeability among
  components.
• Organizational factors.
• Maintenance staff knowledge, documentation
  availability,
• Operative factors.
• Ability of the manpower.
• Is quantified through the MTTR (Mean Time To
  Recovery).

65
Reliability and Statistical availability

• Average between the middle time used in the
  equipment and the required production time
• If the different times between breakdowns as well
  as each repair duration time are graphically
  represented this process.

66
Reliability - the Bathtub curve

• Is a graphic representation of the failure rate
  l(t).
• Probability that an element fails depending on
  its life use stage or status.
• ZONE I. Infant period.
• ZONE II. Useful period.
• ZONE III. Waste period.

67
Reliability The bathtub curve Zone I

• Equipment set up and debug process.
• Goes downhill because, as time moves forward, the
  probability of a component failure decreases.
• The problems in this area can be avoided by
  making intensive tests or by exchanging
  troublemaker elements at an early stage
  adjustment period.

68
Reliability The bathtub curve Zone II and Zone
III

• Zone II.
• Failures randomly appear.
• Electronic systems.
• The curve formed is virtually horizontal.
• In mechanical systems.
• The curve normally has a slightly positive slope.

69
Reliability The bathtub curve Zone II and Zone
III

• Zone III.
• Failures come from components far more quickly.
• Critical components replacement is strongly
  recommended.

70
P-M Analysis

• Defects reasons.
• Sporadic losses.
• Chronic losses.
• Sporadic losses can be corrected using tools
  already studied.

71
P-M Analysis

• The P-M analysis is responsible for eliminating
  chronic losses.
• Considered natural according to their root
  sources.
• P - gt Phenomenon.
• M - gt Mechanism.

72
P-M Analysis

• Reliability that has been studied has two aspects
  to consider.
• Intrinsic reliability.
• Due to the design and production of the
  component.
• Operative reliability.
• Due to the component use and the maintenance
  process.

73
P-M Analysis

• P-M analysis should be applied after conventional
  improvement.
• Six sigma is also suitable to carry out this type
  of study.

74
Maintenance management

• A maintenance department should properly manage
  and control their costs.
• Unlimited number of indicators that can be used
  for maintenance department performance.
• Manpower performance, hours dedicated to urgent
  work, repair cost, availability,...

75
Maintenance management

• Maintenance management is a difficult task
  because it frequently does not have managements
  support.
• As long as the maintenance department does not
  exceed its assigned budget, no one pays much
  attention to the maintenance department
  activities or expenses.

76
Maintenance costs

• Using economic terms, maintenance management
  helps to control deviations in the firms budget
  and also to determine investment needs to reduce
  the costs.

77
Maintenance costs

• There are two alternatives or opposing costs.
• Non-maintenance costs.
• Opportunity costs, quality costs, production
  manpower cost, etc.
• Maintenance costs.
• Breakdown prevention costs, anomalies detection
  cost, inspection resources costs, etc.

78
Maintenance costs

• (1) -gt Maintenance investment increases the
  equipment availability and at the same time
• (2) -gt An increase of the availability, supposes
  large investments.

79
Summary

• This chapter has provided an overview of
  maintenance activities, a critical aspect of Lean
  Manufacturing. Maintenance planning and
  monitoring activities are critical factors for
  Lean Enterprise efficiency.

80
Summary

• Unfortunately, maintenance is normally perceived
  as a necessary evil, and is not always seen as a
  critical engineering activity. This chapter has
  outlined some of the maintenance policies and
  procedures that can be used to obtain the goal
  for any production system operate as efficient
  as possible at the lowest cost.