Reliability Data Collection Reliability Data Collection and Analysisand Analysis
Benbow and Broome (Ch 15, 16 and Benbow and Broome (Ch 15, 16 and 17)17)
Presented by Dr. Joan BurtnerPresented by Dr. Joan BurtnerCertified Quality Engineer Certified Quality Engineer
Associate Professor ofAssociate Professor ofIndustrial Engineering and Industrial Industrial Engineering and Industrial
ManagementManagement
ETM 591 ISE 427 Reliability ETM 591 ISE 427 Reliability DataData
Dr. Joan Burtner, Associate Professor of Industrial Dr. Joan Burtner, Associate Professor of Industrial EngineeringEngineering
Slide Slide 22
OverviewOverview Chapter 15 (Collection)Chapter 15 (Collection)
Types of dataTypes of data Data sourcesData sources Collection methodsCollection methods Management of dataManagement of data
Chapter 16 (Use)Chapter 16 (Use) Summarization of dataSummarization of data Preventive and corrective actionPreventive and corrective action Measures of effectivenessMeasures of effectiveness
Chapter 17 (Failure analysis tools)Chapter 17 (Failure analysis tools) FMEA, FMECAFMEA, FMECA FTAFTA FRACASFRACAS
ETM 591 ISE 427 Reliability ETM 591 ISE 427 Reliability DataData
Dr. Joan Burtner, Associate Professor of Industrial EngineeringDr. Joan Burtner, Associate Professor of Industrial Engineering Slide Slide 33
Censored Failure Data Censored Failure Data Right censored data Right censored data
• Exact failure times collected through the end of the test Exact failure times collected through the end of the test periodperiod
• Some items may still be functioning at end of test periodSome items may still be functioning at end of test period Left censored data Left censored data
• Knowledge that failure happened before a certain timeKnowledge that failure happened before a certain time• Occurs when items are not checked prior to testingOccurs when items are not checked prior to testing• Failure is observed at the first examinationFailure is observed at the first examination
Interval censored dataInterval censored data• Knowledge that failure happened between 2 timesKnowledge that failure happened between 2 times• Occurs when items are checked at intervals (eg. every 2 Occurs when items are checked at intervals (eg. every 2
hrs)hrs)• Failure is observed at the first examinationFailure is observed at the first examination
ETM 591 ISE 427 Reliability ETM 591 ISE 427 Reliability DataData
Dr. Joan Burtner, Associate Professor of Industrial EngineeringDr. Joan Burtner, Associate Professor of Industrial Engineering Slide Slide 44
Reliability Data Reliability Data Sources Sources Laboratory tests before delivery to customerLaboratory tests before delivery to customer
““Clean”Clean” UnrealisticUnrealistic
Field service data (after delivery to customer) Field service data (after delivery to customer) Difficult to determine relevant factorsDifficult to determine relevant factors RealisticRealistic Provides input for future design changesProvides input for future design changes
Note: Most reliability data collection looks at Note: Most reliability data collection looks at failure/non-failure. However, effective managers may failure/non-failure. However, effective managers may collect data on degradation of customer satisfaction collect data on degradation of customer satisfaction with non-failed products or processeswith non-failed products or processes
ETM 591 ISE 427 Reliability ETM 591 ISE 427 Reliability DataData
Dr. Joan Burtner, Associate Professor of Industrial EngineeringDr. Joan Burtner, Associate Professor of Industrial Engineering Slide Slide 55
Reliability Data Reliability Data Management Management Design of the product failure Design of the product failure
database should involve a variety database should involve a variety of stakeholders.of stakeholders.
What data will be collected?What data will be collected? Where will the data be kept?Where will the data be kept? Who will have access to the data?Who will have access to the data? How long will the data be kept?How long will the data be kept? What are the backup and security What are the backup and security
procedures?procedures?
ETM 591 ISE 427 Reliability ETM 591 ISE 427 Reliability DataData
Dr. Joan Burtner, Associate Professor of Industrial EngineeringDr. Joan Burtner, Associate Professor of Industrial Engineering Slide Slide 66
Data Summarization Data Summarization CalculationsCalculations
Hazard function – failure rate as a Hazard function – failure rate as a function of timefunction of time
λλ (t) = (t) = Fraction of failures during time periodFraction of failures during time period Amount of time during the periodAmount of time during the period
Reliability function – reliability as a Reliability function – reliability as a function of timefunction of time
R(t) = R(t) = Number surviving at the end of the time Number surviving at the end of the time period period
Number of units testedNumber of units tested
ETM 591 ISE 427 Reliability ETM 591 ISE 427 Reliability DataData
Dr. Joan Burtner, Associate Professor of Industrial EngineeringDr. Joan Burtner, Associate Professor of Industrial Engineering Slide Slide 77
Data Presentation Data Presentation Control ChartsControl Charts HistogramsHistograms Probability density function graphsProbability density function graphs Cause and effect diagramsCause and effect diagrams Scatter diagramsScatter diagrams Pareto chartsPareto charts Comparisons of before/after preventative or Comparisons of before/after preventative or
corrective action initiativescorrective action initiatives
ETM 591 ISE 427 Reliability ETM 591 ISE 427 Reliability DataData
Dr. Joan Burtner, Associate Professor of Industrial EngineeringDr. Joan Burtner, Associate Professor of Industrial Engineering Slide Slide 88
Ch. 17 Tools - FMEA Ch. 17 Tools - FMEA Failure Mode and Effects Analysis (FMEA)Failure Mode and Effects Analysis (FMEA) Purpose: “anticipation and migration of the Purpose: “anticipation and migration of the
negative effects of possible failures before they negative effects of possible failures before they occur.”occur.”
Ideally implemented by a cross-functional team Ideally implemented by a cross-functional team that may even include customersthat may even include customers
Applicable to all stages from product and process Applicable to all stages from product and process design and through deliverydesign and through delivery
Includes the development of risk priority values Includes the development of risk priority values which are subject to interpretationwhich are subject to interpretation
ETM 591 ISE 427 Reliability ETM 591 ISE 427 Reliability DataData
Dr. Joan Burtner, Associate Professor of Industrial EngineeringDr. Joan Burtner, Associate Professor of Industrial Engineering Slide Slide 99
FMEA Process Steps FMEA Process Steps Develop team, collect data, identify all possible Develop team, collect data, identify all possible
failure modes.failure modes. Calculate risk priority number (rpn) for each Calculate risk priority number (rpn) for each
mode based on estimations of severity (S), mode based on estimations of severity (S), occurrence (O), and detection (D).occurrence (O), and detection (D). Estimations typically range from 1 to 10.Estimations typically range from 1 to 10. There are many acceptable guidelines for assigning the There are many acceptable guidelines for assigning the
values.values. The rpn for each mode equals S x O x D. The rpn for each mode equals S x O x D.
Prioritize failure modes and interpret the results.Prioritize failure modes and interpret the results.
ETM 591 ISE 427 Reliability ETM 591 ISE 427 Reliability DataData
Dr. Joan Burtner, Associate Professor of Industrial EngineeringDr. Joan Burtner, Associate Professor of Industrial Engineering Slide Slide 1010
FMEA Interpretation FMEA Interpretation Traditional method: Sort failure modes by rpn number and Traditional method: Sort failure modes by rpn number and
address modes with highest rpn numbers first.address modes with highest rpn numbers first. Because we are dealing with estimations, look for natural groupings Because we are dealing with estimations, look for natural groupings
rather than absolute ranks.rather than absolute ranks. May use product of severity and detection to break ties.May use product of severity and detection to break ties.
Alternative method: Do not calculate rpn. Instead, sort by Alternative method: Do not calculate rpn. Instead, sort by severity rank, then occurrence rank, and finally detection severity rank, then occurrence rank, and finally detection rank.rank. This allows you to address all of the highest severity failure modes before This allows you to address all of the highest severity failure modes before
the medium and lower severity modes.the medium and lower severity modes. Regardless of the method used, preventive and corrective Regardless of the method used, preventive and corrective
action plans should be developed for high priority failure action plans should be developed for high priority failure modes.modes.
Thorough documentation is essential.Thorough documentation is essential.
ETM 591 ISE 427 Reliability ETM 591 ISE 427 Reliability DataData
Dr. Joan Burtner, Associate Professor of Industrial EngineeringDr. Joan Burtner, Associate Professor of Industrial Engineering Slide Slide 1111
Ch. 17 Tools - FMECA Ch. 17 Tools - FMECA Failure Mode and Effects and Criticality Analysis Failure Mode and Effects and Criticality Analysis
(FMECA)(FMECA) Purpose same as FMEAPurpose same as FMEA FMECA uses Severity (S) and Occurrence (O) FMECA uses Severity (S) and Occurrence (O)
ratings on a scale of 1 to 10, where 10 is highest.ratings on a scale of 1 to 10, where 10 is highest. Values are not multiplied. Instead they are placed Values are not multiplied. Instead they are placed
on a graph with S on x-axis and O on y-axison a graph with S on x-axis and O on y-axis Failure modes in the top right quadrant are Failure modes in the top right quadrant are
addressed first.addressed first.
ETM 591 ISE 427 Reliability ETM 591 ISE 427 Reliability DataData
Dr. Joan Burtner, Associate Professor of Industrial EngineeringDr. Joan Burtner, Associate Professor of Industrial Engineering Slide Slide 1212
Ch. 17 Tools – FTA and Ch. 17 Tools – FTA and STASTA Fault Tree Analysis (FTA) Fault Tree Analysis (FTA) Success Tree Analysis (STA)Success Tree Analysis (STA) Graphical representation of identified failure modeGraphical representation of identified failure mode Purpose to help identify root cause of product failure Purpose to help identify root cause of product failure
or steps to help ensure product successor steps to help ensure product success See Figure 17.1 (input/output symbols) p.227 See Figure 17.1 (input/output symbols) p.227 See Figure 17.2 and 6.2 for complete FTA diagramsSee Figure 17.2 and 6.2 for complete FTA diagrams See Figure 17.4 STA diagramSee Figure 17.4 STA diagram Voting OR gate p.228Voting OR gate p.228
ETM 591 ISE 427 Reliability ETM 591 ISE 427 Reliability DataData
Dr. Joan Burtner, Associate Professor of Industrial EngineeringDr. Joan Burtner, Associate Professor of Industrial Engineering Slide Slide 1313
Ch. 17 Tools - FRACAS Ch. 17 Tools - FRACAS Failure Reporting, Analysis, and Corrective Action Failure Reporting, Analysis, and Corrective Action
System (FRACAS)System (FRACAS) Provides an organized, disciplined approach for Provides an organized, disciplined approach for
dealing with failures that actually occur.dealing with failures that actually occur. Guidelines for implementing FRACASGuidelines for implementing FRACAS
Assign responsibility for FRACAS implementation to Assign responsibility for FRACAS implementation to individual or departmentindividual or department
Require that all failures be reported promptlyRequire that all failures be reported promptly Apply FRACAS throughout the product life cycleApply FRACAS throughout the product life cycle Develop timelines for analysis and corrective / preventive Develop timelines for analysis and corrective / preventive
actions and reportsactions and reports Alert next higher level of management WRT non-Alert next higher level of management WRT non-
compliance issues compliance issues
ETM 591 ISE 427 Reliability ETM 591 ISE 427 Reliability DataData
Dr. Joan Burtner, Associate Professor of Industrial EngineeringDr. Joan Burtner, Associate Professor of Industrial Engineering Slide Slide 1414
ReferencesReferences Course Text:Course Text:
Benbow, D.W. and Broome, H.W., Ed. (2009). Benbow, D.W. and Broome, H.W., Ed. (2009). The The Certified Reliability Engineer HandbookCertified Reliability Engineer Handbook . . Milwaukee,WI: ASQ Quality Press.Milwaukee,WI: ASQ Quality Press.
Additional Sources Additional Sources Christensen, E.H., Coombes-Betz, K.M., and Stein, Christensen, E.H., Coombes-Betz, K.M., and Stein,
M.S. (2006). M.S. (2006). The Certified Quality Process Analyst The Certified Quality Process Analyst HandbookHandbook. Milwaukee: ASQ Quality Press.. Milwaukee: ASQ Quality Press.
Westcott, R.T., Ed. (2006). Westcott, R.T., Ed. (2006). Certified Manager of Certified Manager of Quality/Organizational Excellence HandbookQuality/Organizational Excellence Handbook (3 (3rdrd ed.). Milwaukee: ASQ Quality Press.ed.). Milwaukee: ASQ Quality Press.
ETM 591 ISE 427 Reliability ETM 591 ISE 427 Reliability DataData
Dr. Joan Burtner, Associate Professor of Industrial Dr. Joan Burtner, Associate Professor of Industrial EngineeringEngineering
Slide Slide 1515
Contact InformationContact Information Email: [email protected]: [email protected] US Mail:US Mail:
Mercer University School of Mercer University School of Engineering Engineering 1400 Coleman Avenue 1400 Coleman Avenue Macon, GAMacon, GA
Phone: (478) 301- 4127Phone: (478) 301- 4127
