Post on 14-Feb-2017
Preventive Maintenance Principles
SPL 7.2 Scott Couzens, LFM ’06 Scott Hiroshige, LFM ‘06
Presentation for:
Summer 2004
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Erik Smith, LFM ’03 – Intel Corporation
ESD.60 – Lean/Six Sigma Systems MIT Leaders for Manufacturing Program (LFM)
These materials were developed as part of MIT's ESD.60 course on "Lean/Six Sigma Systems." In some cases, the materials were produced by the lead instructor, Joel Cutcher-Gershenfeld, and in some cases by student teams
working with LFM alumni/ae. Where the materials were developed by student teams, additional nputs from the faculty and from the technical instructor, Chris Musso, are reflected in some of the text or in an appendix
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Special Thanks to:
¾ DNS Employees: ¾ Roger Nuffer ¾ David Villareal ¾ Marcus Hunsaker
¾ Intel Employees: ¾ Jonathan Matthews ¾ David Latham ¾ Eli Sorenson ¾ Danny Miller
9/04 --LFM Students] – ESD.60 Lean Six Sigma Systems, LFM, MIT
Part I: Introduction Part II: Concepts Part III: Application Part IV: Disconnects Part V: Conclusion
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Overview ¾ Learning Objectives ¾
types of maintenance activities
¾ Appreciation of the benefits of preventive maintenance
¾ Understanding of lean principreventive maintenance schedule
¾ Awareness of specific challenges to implementing preventive maintenance
¾ Session Design (20-30 min.) ¾ Part I: Introduction and Learning
Objectives (1-2 min.) ¾ Part II: Key Concept or Principle
Defined and Explained (3-5 min.) ¾ Part III: Exercise or Activity
Based on Field Data that Illustrates the Concept or Principle (7-10 min.)
¾ Part IV: Common “Disconnects,” Relevant Measures of Success, and Potential Action Assignment(s) to Apply Lessons Learned (7-10 min.)
¾ Part V: Evaluation and Concluding Comments (2-3 min.)
9/04 --LFM Students] – ESD.60 Lean Six Sigma Systems, LFM, MIT
Familiarity with the different
ples for designing a
Part I: Introduction Part II: Concepts Part III: Application Part IV: Disconnects Part V: Conclusion
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Types of Maintenance
¾ Breakdown Maintenance: ¾ Waiting until equipment fails before repairing or servicing it
¾ Preventive Maintenance (PM): ¾
cleaning, or replacing parts to prevent sudden failure ¾ (Predictive) On-line monitoring of equipment in order to use
important/expensive parts to the limit of their serviceable life
¾ Corrective or Predictive Maintenance: ¾ Improving equipment and its components so that preventive
maintenance can be carried out reliably
9/04 --LFM Students] – ESD.60 Lean Six Sigma Systems, LFM, MIT
Part I: Introduction Part II: Concepts Part III: Application Part IV: Disconnects Part V: Conclusion
(Time-based or run-based) Periodically inspecting, servicing,
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Benefits of Preventive Maintenance
¾ “…the cost of breakdown maintenance is usually much greater than preventive maintenance.” 1
¾ Preventive maintenance… ¾ Keeps equipment in good condition to prevent large problems ¾ Extends the useful life of equipment ¾ Finds small problems before they become big ones ¾ Is an excellent training tool for technicians ¾ Helps eliminate rework/scrap and reduces process variability ¾ Keeps equipment safer ¾ Parts stocking levels can be optimized ¾ Greatly reduces unplanned downtime
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9/04 --LFM Students] – ESD.60 Lean Six Sigma Systems, LFM, MIT
Part I: Introduction Part II: Concepts Part III: Application Part IV: Disconnects Part V: Conclusion
http://www.prenhall.com divisions/bp/app/russel cd/PROTECT/CHAPTERS/CHAP15/HEAD01.HTM
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The Manufacturing Game
¾ Similar to the Beer Game ¾ Simulates a typical plant with three roles: ¾ Operations Manager ¾ Maintenance Manager ¾ Spare Parts Stores Manager
¾ Each round, participants make decisions such as: ¾ Which equipment to take down for PMs ¾ How to allocate maintenance resources ¾ How many spare parts to order
¾ Revenue, cost, output, uptime, inventory are recorded
i
9/04 --LFM Students] – ESD.60 Lean Six Sigma Systems, LFM, MIT
Part I: Introduction Part II: Concepts Part III: Application Part IV: Disconnects Part V: Conclusion
Source: Business Dynam cs: Systems Thinking and Modeling for a Complex World, Sterman, John D., 2000.
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The Manufacturing Game Results
¾ Teams who follow a cost-minimization strategy (reactive maintenance policies) are able to keep costs low for a
uptime falling and costs rising. ¾ Teams who follow a preventive maintenance strategy
initially find higher costs and reduced uptime as equipment is taken offline for planned maintenance. Soon, however, these teams begin to greatly outperform teams following a cost-minimization strategy.
i
9/04 --LFM Students] – ESD.60 Lean Six Sigma Systems, LFM, MIT
Part I: Introduction Part II: Concepts Part III: Application Part IV: Disconnects Part V: Conclusion
while. However, as defects build up they find their
Source: Business Dynam cs: Systems Thinking and Modeling for a Complex World, Sterman, John D., 2000.
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When Does PM Make Sense?
¾ PM makes sense when the cost of doing PM is less than the cost of NOT doing PM.
¾ CDoingPM =
and man-hours consumed in PM, potential for making things worse, etc.)
¾ CNotDoingPM = makes no difference in preventing the failure), materials and man-hours spent repairing equipment, loss of
etc.)
PM makes sense if C < C
9/04 --LFM Students] – ESD.60 Lean Six Sigma Systems, LFM, MIT
Part I: Introduction Part II: Concepts Part III: Application Part IV: Disconnects Part V: Conclusion
f(hours of not running equipment, loss in employee morale from doing PM instead of “real work”, materials
f(cost of losing/reworking a failed batch (unless PM
equipment lifetime, loss in employee morale from NOT doing PM, reduced employee familiarity with equipment,
DoingPM NotDoingPM
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Optimizing a PM Schedule
¾ Question: ¾ If a certain piece of production equipment requires ~10 hours of
preventive maintenance per week, how should those 10 hours be scheduled?
¾ Answer: ¾ In a 24x7 manufacturing operation, it is typically better to
perform the ~10 hours of activities in several smaller periods of time, for instance 5 PM activities that take ~2 hours each
¾ Duration and variability in preventive maintenance are key factors in whether equipment will be able to maintain a steady flow of output
9/04 --LFM Students] – ESD.60 Lean Six Sigma Systems, LFM, MIT
Part I: Introduction Part II: Concepts Part III: Application Part IV: Disconnects Part V: Conclusion
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PM Durations: Simulation 1 ¾
hours (85% availability)
0
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450
()
Drop Page Fields Here
io
9/04 --LFM Students] – ESD.60 Lean Six Sigma Systems, LFM, MIT
Part I: Introduction Part II: Concepts Part III: Application Part IV: Disconnects Part V: Conclusion
Simulation of equipment with a 10 hour average PM duration, std dev 20
Trend of Queues for the Toolset
83 88 99 109114119125133139147152157162167172177182187192198203211216221226231236241246267
Days into Sim ulation
Ave
rage
Que
ueLe
ngth
# o
f Lot
s
1 - 10h mean, 2 CV
Avg Queuelength
Day
Scenar
Data from a simulation run at Intel Fab 11X.
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PM Durations: Simulation 2 ¾
hours (85% availability)
0
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100
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200
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450
83 88 93
()
Drop Page Fields Here
io
9/04 --LFM Students] – ESD.60 Lean Six Sigma Systems, LFM, MIT
Part I: Introduction Part II: Concepts Part III: Application Part IV: Disconnects Part V: Conclusion
Simulation of equipment with a 5 hour average PM duration, std dev 10
Trend of Queues for a Toolset
98 103 108 113 118 125 137 155 164 194 201 213 228 233 244 259 264 277 285
Days into Sim ulation
Ave
rage
Que
ueLe
ngth
# o
f Lot
s
2 - 5h mean, 2 CV
Avg Queuelength
Day
Scenar
Data from a simulation run at Intel Fab 11X.
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PM Durations: Simulation 3 ¾
hours (85% availability)
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50
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200
250
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450
84 91 102 125 148 160 173 196 209 225 238 273 279 287
()
Drop Page Fields Here
io
9/04 --LFM Students] – ESD.60 Lean Six Sigma Systems, LFM, MIT
Part I: Introduction Part II: Concepts Part III: Application Part IV: Disconnects Part V: Conclusion
Simulation of equipment with a 2 hour average PM duration, std dev 4
Trend of Queues for a Toolset
116 138 230 261
Days into Sim ulation
Ave
rage
Que
ueLe
ngth
# o
f Lot
s
3 - 2h mean, 2 CV
Avg Queuelength
Day
Scenar
Data from a simulation run at Intel Fab 11X.
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PM Durations: Simulation 4 ¾
hours (85% availability)
0
50
84
l
9/04 --LFM Students] – ESD.60 Lean Six Sigma Systems, LFM, MIT
Part I: Introduction Part II: Concepts Part III: Application Part IV: Disconnects Part V: Conclusion
Simulation of equipment with a 2 hour average PM duration, std dev 6
Trend of Queues for a Toolset
100
150
200
250
300
350
400
450
98 112 117 122 127 133 138 143 148 153 158 163 168 173 178 183 188 193 204 222 242 258 264 275 286 291
Days into Simulation
Aver
age
Que
ueLe
ngth
(# o
f Lot
s)
4 - 2h mean, 3 CV
Drop Page Fie ds Here
Avg Queuelength
Day
Scenario
Data from a simulation run at Intel Fab 11X.
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PM Durations: Why they matter ¾ For the exact same availability on a piece of equipment:
¾ Shorter PM durations mean a difference in days of lotcycle time! ¾
¾ Regardless of the mean, performing PMs inconsistentlyis functionally equivalent to consistently having muchlonger downtime durations
57564) µ=2h, σ=6h 883) µ=2h, σ=4h 52382) µ=5h, σ=10h 63561) µ=10h, σ=20h
StdDev QueueLengthAvg QueueLengthSimulation
9/04 --LFM Students] – ESD.60 Lean Six Sigma Systems, LFM, MIT
Part I: Introduction Part II: Concepts Part III: Application Part IV: Disconnects Part V: Conclusion
Each day of factory cycle time = millions of $$
Data from simulations run at Intel Fab 11X.
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The “Waddington Effect”
¾ First observed by C.H. Waddington during WWII forBritish aircraft maintenance
¾ Background theory: unscheduled downtime shouldbe a random phenomenon
¾ If all unscheduled downtime events are plotted withrespect to the last PM, there should not be anypattern evident
¾ A pattern of increased unscheduled downtimeimmediately following PM’s is a “WaddingtonEffect”
9/04 --LFM Students] – ESD.60 Lean Six Sigma Systems, LFM, MIT
Part I: Introduction Part II: Concepts Part III: Application Part IV: Disconnects Part V: Conclusion
Information from a presentation given at Intel Fab 11X.
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The “Waddington Effect”
0
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0.5 1 1.5 2 2.5 3 3.5 4 4.5
¾
9/04 --LFM Students] – ESD.60 Lean Six Sigma Systems, LFM, MIT
Part I: Introduction Part II: Concepts Part III: Application Part IV: Disconnects Part V: Conclusion
"Waddington Effect" Report - Trend of Unscheduled Downtime Frequency Following PMs for the last 12 work weeks
Days since End of Last PM
# of
Uns
ched
uled
Dow
n Ev
ents
REPAIR QUAL OUT OF CNTRL
# of Unsched Downs
Days Since PM
Event_Type
Impact of Waddington Effect = 1.4% Availability
Data from a set of production tools at Intel Fab 11X.
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Challenges to Implementing Preventive Maintenance
¾ Technical Factors
¾ Breakdown maintenance
preventive maintenancein the short-term
¾ Under-trained technicians can cause more damage
¾ Social Factors
¾ Organizations are
output goals, etc.)
¾
always well understood
¾ The focus on minimizing
organizationalperformance
9/04 --LFM Students] – ESD.60 Lean Six Sigma Systems, LFM, MIT
is typically cheaper than
than they prevent
frequently structured in ways that promote local optimums (cost, shiftly
The benefits of preventive maintenance are not
maintenance costs has to shift to maximizing overall
Part I: Introduction Part II: Concepts Part III: Application Part IV: Disconnects Part V: Conclusion
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Concluding Comments
¾ Performing preventive maintenance is almost always the bestlong-term strategy to maintain equipment
¾ PM scheduling and strategy are keys to maximizing outputwhile reducing work-in-process inventory
¾ Due to short-term cost increases and local optimums, there arebarriers to implementing a preventive maintenance strategy atsome plants
9/04 --LFM Students] – ESD.60 Lean Six Sigma Systems, LFM, MIT
Part I: Introduction Part II: Concepts Part III: Application Part IV: Disconnects Part V: Conclusion
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Appendix: Instructor’s Comments and Class Discussion for 7.2
¾ PM is an important tool for establishing stability necessary for other lean elements: ¾ Andon, 5s, etc.
¾ How do you escape the crisis management whirlpool? ¾ Social disconnects: ¾Change the mindset of management, maintenance
group from reaction to prevention ¾May need to be done in steps
9/04 --LFM Students] – ESD.60 Lean Six Sigma Systems, LFM, MIT
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Appendix: Instructor’s Guide
•1-2 min17
•Disconnects2-3 min16
• Game • i• Discuss “Waddington Effect”
Exercises/Activities6-15
4-5
1-3
Slide
• •
Key Concepts3-5 min
• • iveslearning objectives
2-3 min
Additional Talking PointsTopicTime
9/04 --LFM Students] – ESD.60 Lean Six Sigma Systems, LFM, MIT
Summarize key points of preventive maintenance Concluding comments
Discuss the difficulties of implementing preventive maintenance in a reactive maintenance culture
Go through the key learnings of the Manufacturing
Go through a PM optim zation example
7-15 min
Describe the 3 types of maintenance Explain the benefits of preventive maintenance
Acknowledge contributors to the presentation Provide an overview of the learning object
Introduction, overview and
Part I: Introduction Part II: Concepts Part III: Application Part IV: Disconnects Part V: Conclusion