Reliability Engineering
Fred Schenkelberg
fms@fmsreliability.com
USING FIELD AND TEST DATA TO
ESTIMATE RELIABILITY
Day 1 Session 4
Objectives
• Discussing reliability data types
• Considering complete and censored data
• Analyzing trend plotting, 80-20 ...
Reliability Data Types
• CMMS data
• Process data
• Life data
• Time to Failure data
Reliability Data Types
• Pass/Fail data
• Attribute data
• Time or cycles to failure
• Variables data
• Start and stop
def...
Reliability Data Types
• Complete data
– All units have failed
• Censored data
– Right censored – not all
have failed yet
...
Reliability Data Types
• Non-repairable data
All start at time zero
Reliability Data Types
• repairable data
All start at time zero
Discussion & Questions
Trend Plotting
Advantages
• Easy
• Visual
• Actual data
Disadvantages
• Difficult to see changes
• Lagging indicator
• May...
80 – 20 or Pareto plotting
Advantages
• Easy
• Visual
• Prioritization build in
Disadvantages
• Difficult to see changes o...
CountorFrequency
Life Data CDF
Advantages
• Accounts for all data
• Visual
• Easy to read
Disadvantages
• Difficult to see changes
• Requir...
MCF plotting
Advantages
• Very Easy to create
• Easy to see patterns
Disadvantages
• Difficult to summarize
• Requires mor...
Wayne Nelson, Graphical Analysis of Repair Data
Discussion & Questions
Weibull Plotting with Weibull++
• Data preparation
• Basic algorithm
• Censored data handing
• For more details
• www.weib...
Reading a Weibull CDF Plot
MCF plotting
• Data Preparation
• Basic algorithm
• For more information
• Trindade paper, book,
Nelsons paper, book
Reading an MCF plot
Discussion & Questions
Plot labeling
• Title
• Data source
• Data timeframe
• Axis labels and units
Report Data
• Regular reports
• Project reports
• Analysis reports
• Recommendation
reports
Comparisons over time
• Break up data by time
– Before/after change
– Before/after experiment
– Before/after overhaul
• La...
Data collection over time
• Vendor data
• Installation
• Maintenance
• Decommissioning
Discussion & Questions
Summary
• Discussing reliability data
types
• Considering complete and
censored data
• Analyzing trend plotting, 80-
20 pl...
Reliability Maintenance Engineering 1 - 4 Estimating Reliability
Reliability Maintenance Engineering 1 - 4 Estimating Reliability
Reliability Maintenance Engineering 1 - 4 Estimating Reliability
Reliability Maintenance Engineering 1 - 4 Estimating Reliability
Reliability Maintenance Engineering 1 - 4 Estimating Reliability
Reliability Maintenance Engineering 1 - 4 Estimating Reliability
Reliability Maintenance Engineering 1 - 4 Estimating Reliability
Reliability Maintenance Engineering 1 - 4 Estimating Reliability
Reliability Maintenance Engineering 1 - 4 Estimating Reliability
Reliability Maintenance Engineering 1 - 4 Estimating Reliability
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Reliability Maintenance Engineering 1 - 4 Estimating Reliability

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Reliability Maintenance Engineering Day 1 session 4 Estimating Reliability
Three day live course focused on reliability engineering for maintenance programs. Introductory material and discussion ranging from basic tools and techniques for data analysis to considerations when building or improving a program.

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Reliability Maintenance Engineering 1 - 4 Estimating Reliability

  1. 1. Reliability Engineering Fred Schenkelberg fms@fmsreliability.com
  2. 2. USING FIELD AND TEST DATA TO ESTIMATE RELIABILITY Day 1 Session 4
  3. 3. Objectives • Discussing reliability data types • Considering complete and censored data • Analyzing trend plotting, 80-20 plots and statistical plots • Drawing a best-fit regression line with Weibull • Recording data related to reliability performance • Providing continuity in data collection systems
  4. 4. Reliability Data Types • CMMS data • Process data • Life data • Time to Failure data
  5. 5. Reliability Data Types • Pass/Fail data • Attribute data • Time or cycles to failure • Variables data • Start and stop definitions
  6. 6. Reliability Data Types • Complete data – All units have failed • Censored data – Right censored – not all have failed yet – Left censored – not sure when some started – Interval censored – not sure when failure occurred between inspections.
  7. 7. Reliability Data Types • Non-repairable data All start at time zero
  8. 8. Reliability Data Types • repairable data All start at time zero
  9. 9. Discussion & Questions
  10. 10. Trend Plotting Advantages • Easy • Visual • Actual data Disadvantages • Difficult to see changes • Lagging indicator • May require adjustments for scheduled downtime
  11. 11. 80 – 20 or Pareto plotting Advantages • Easy • Visual • Prioritization build in Disadvantages • Difficult to see changes over time • Doesn’t include costs impact
  12. 12. CountorFrequency
  13. 13. Life Data CDF Advantages • Accounts for all data • Visual • Easy to read Disadvantages • Difficult to see changes • Requires probability paper or software • Requires time to failure data CDF – Cumulative Distribution Function -
  14. 14. MCF plotting Advantages • Very Easy to create • Easy to see patterns Disadvantages • Difficult to summarize • Requires more than two failures/repairs per equipment • Doesn’t account for scheduled downtime or extended repairs MCF – Mean Cumulative Function
  15. 15. Wayne Nelson, Graphical Analysis of Repair Data
  16. 16. Discussion & Questions
  17. 17. Weibull Plotting with Weibull++ • Data preparation • Basic algorithm • Censored data handing • For more details • www.weibul.com
  18. 18. Reading a Weibull CDF Plot
  19. 19. MCF plotting • Data Preparation • Basic algorithm • For more information • Trindade paper, book, Nelsons paper, book
  20. 20. Reading an MCF plot
  21. 21. Discussion & Questions
  22. 22. Plot labeling • Title • Data source • Data timeframe • Axis labels and units
  23. 23. Report Data • Regular reports • Project reports • Analysis reports • Recommendation reports
  24. 24. Comparisons over time • Break up data by time – Before/after change – Before/after experiment – Before/after overhaul • Labels • Show magnitude of impact clearly, if any.
  25. 25. Data collection over time • Vendor data • Installation • Maintenance • Decommissioning
  26. 26. Discussion & Questions
  27. 27. Summary • Discussing reliability data types • Considering complete and censored data • Analyzing trend plotting, 80- 20 plots and statistical plots • Drawing a best-fit regression line with Weibull • Recording data related to reliability performance • Providing continuity in data collection systems Using field and test data to estimate reliability
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