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Failure Mode and Effect Analysis. *. Learning Objectives. Provide familiarization with FMEA principles and techniques. Summarize the concepts, definitions, application options and relationships with other tools. Learn how to integrate FMEA into your Company SOPs. *. Definition of FMEA.
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* Learning Objectives • Provide familiarization with FMEA principles and techniques. • Summarize the concepts, definitions, application options and relationships with other tools. • Learn how to integrate FMEA into your Company SOPs
* Definition of FMEA FMEA is asystematicdesign evaluation procedure whose purpose is to: 1. recognize and evaluatethe potential failure modes and causes associated with the designing and manufacturing of a new product or a change to an existing product, 2.identifyactions which could eliminate or reduce the chance of the potential failure occurring, 3.documentthe process.
Manufacturing Engineer Supplier Quality Design Engineer Reliability Engineer Production Program Management * FMEA is Function-driven FMEA begins with a definition of the FUNCTIONS an item is supposed to perform. The inputs must come from several sources to be effective:
* Background Developed in early 60’s by NASA to “fail-proof” Apollo missions. Adopted in early 70’s by US Navy . By late 80’s, automotive industry had implemented FMEA and began requiring suppliers do the same. Liability costs were the main driving force. Used sporadically throughout industry during 1980’s. Adopted by Seagate in 1996. Initial application in design centers. Now it’s time to apply FMEA to process applications in Seagate. Six Sigma is the catalyst.
NASA used FMEA to identify Single Point Failures on Apollo project (SPF = no redundancy & loss of mission). How many did they find? 420 and we thought we had No problems!
* Types of FMEA’s System FMEA is used to analyze systems and subsystems in the early concept and design stages. SYSTEM Design FMEA is used to analyze products before they are released to production DESIGN Process FMEA is used to analyze manufacturing, assembly and administrative processes PROCESS
When Is the FMEA Started? AS EARLY AS POSSIBLE Do the best you can with what you have. Guideline:
When to Start • When new systems, products and processes are being designed • When existing designs and processes are being changed • When carry-over designs or processes will be used in new applications or environments • After completing a Problem Solving Study, to prevent recurrence of a problem
* Process FMEA Form
Process Failure Mode • The potential failure mode is the manner in which the process could fail to perform its intended function. • The failure mode for a particular operation could be a cause in a subsequent (downstream) operation or an effect in associated with a potential failure in a previous (upstream) operation. PREVIOUS OPERATION NEXT OPERATION FAILURE MODE EFFECT CAUSE
OPERATOR SET-UP MACHINE METHOD ENVIRONMENT MEASUREMENT Process Causes Process FMEA considers process variability due to:
Current Controls • Assessment of the ability of the control to detect the failure before the item leaves the manufacturing area and ships to the customer. • Capability of all controls in the process to prevent escapes Process Capability Sampling DoE Testing Gage R&R SPC
* Types of Measures Typically, three items are scored: SEVERITY As it applies to the effects on the local system, next level, and end user OCCURRENCE Likelihood that a specific cause will occur and result in a specific failure mode DETECTION Ability of the current / proposed control mechanism to detect and identify the failure mode
Detection (“Escape”) This is best thought of as Escape Potential - the higher the score, the greater the problem
* Risk Priority Number RPN = O x S x D Occurrence x Severity x Detection
Basic Steps • Develop a Strategy • Form a FMEA team
Basic Steps 1. Develop a Strategy 2. Review the design/process • Develop process map and identify all process steps
Basic Steps 1. Develop a Strategy 2. Review the design /process 3.List functions • List all the value-added process • For each process step, list process inputs (process characteristics
CAUSES EFFECT Basic Steps 1. Develop a Strategy 2. Review the design /process 3. List functions 4. Brainstorm potential failure modes
Basic Steps 1. Develop a Strategy 2. Review the design /process 3. List functions 4. Brainstorm potential failure modes 5. List the potential consequences of each failure mode
PRODUCT: FMEA NO. PROCESS/OPERATION: PAGE OF PLANNING REFERENCE: DATE: BY: DESIGN (OR PROCESS) FMEA Oklahoma City SEVERITY OCCURRENCE DETECTION RPN = S x O x D S O D RPN RESULTING ACTION POTENTIAL POTENTIAL POTENTIAL CURRENT CORRECTIVE RESPONSIBILITY ACTION FUNCTION FAILURE MODE EFFECTS OF CAUSE(S) OF CONTROLS PRIORITY ACTION & DATE DUE TAKEN S O D RPN FAILURE FAILURE Basic Steps 1. Develop a Strategy 2. Review the design /process 3. List functions 4. Brainstorm potential failure modes 5. List the potential consequences of each failure mode 6. Assign severity (SEV) score
Basic Steps 1. Develop a Strategy 2. Review the design /process 3. List functions 4. Brainstorm potential failure modes 5. List the potential consequences of each failure mode 6. Assign severity (SEV) score 7. Identify the cause(s) of each failure mode.
Basic Steps 1. Develop a Strategy 2. Review the design /process 3. List functions 4. Brainstorm potential failure modes 5. List the potential consequences (effect) of each failure mode 6. Assign severity (SEV) score 7. Identify the cause(s) of each failure mode. 8. Assign occurrence (OCC) scores.
Basic Steps 1. Develop a Strategy 2. Review the design /process 3. List functions 4. Brainstorm potential failure modes 5. List the potential consequences (effect) of each failure mode 6. Assign severity (SEV) score 7. Identify the potential cause(s) of each failure mode. 8. Assign occurrence (OCC) scores. 9. Identify current controls to detect the failure modes.
Basic Steps 1. Develop a Strategy 2. Review the design /process 3. List functions 4. Brainstorm potential failure modes 5. List the potential consequences (effect) of each failure mode 6. Assign severity (SEV) score 7. Identify the potential cause(s) of each failure mode. 8. Assign occurrence (OCC) scores. 9. Identify current controls to detect the failure modes. 10. Assign an escaped detection (DET) score for each cause and control.
Basic Steps 1. Develop a Strategy 2. Review the design /process 3. List functions 4. Brainstorm potential failure modes 5. List the potential consequences (effect) of each failure mode 6. Assign severity (SEV) score 7. Identify the potential cause(s) of each failure mode. 8. Assign occurrence (OCC) scores. 9. Identify current controls to detect the failure modes. 10. Assign an escaped detection (DET) score for each cause and control. 11. Calculate the Risk Priority Numer (RPN) for each line in the FMEA.
Basic Steps 1. Develop a Strategy 2. Review the design /process 3. List functions 4. Brainstorm potential failure modes 5. List the potential consequences (effect) of each failure mode 6. Assign severity (SEV) score 7. Identify the potential cause(s) of each failure mode. 8. Assign occurrence (OCC) scores. 9. Identify current controls to detect the failure modes. 10. Assign an escaped detection (DET) score for each cause and control. 11. Calculate the Risk Priority Numer (RPN) for each line in the FMEA. 12. Determine the action to be taken.
Basic Steps 1. Develop a Strategy 2. Review the design /process 3. List functions 4. Brainstorm potential failure modes 5. List the potential consequences (effect) of each failure mode 6. Assign severity (SEV) score 7. Identify the potential cause(s) of each failure mode. 8. Assign occurrence (OCC) scores. 9. Identify current controls to detect the failure modes. 10. Assign an escaped detection (DET) score for each cause and control. 11. Calculate the Risk Priority Numer (RPN) for each line in the FMEA. 12. Determine the action to be taken. 13. Recalculate the RPNs based on the actions plans.
* Shortcomings of RPN Effectiveness RPN Occurrence Failure Mode A 84 3 96 B 48 3 96 Severity SAME RESULT
INITIAL PROBLEM POTENTIAL PROBLEM WALK INTO DOOR LIKELY CAUSE LIKELY EFFECT CAN’T SEE BUMP HEAD PAIN TRIGGER PREVENTIVE ACTIONS CONTINGENT - ADAPTIVE -CORRECTIVE GET GLASSES WEAR HELMET REMOVE DOORS
1st WHY PROBLEM BECOMES EFFECT CAUSE BECOMES NEW PROBLEM POTENTIAL PROBLEM WALK INTO DOOR LIKELY CAUSE LIKELY EFFECT CAN’T SEE BUMP HEAD PAIN TRIGGER PREVENTIVE ACTIONS CONTINGENT - ADAPTIVE -CORRECTIVE GET GLASSES WEAR HELMET REMOVE DOORS
1st WHY CAN’T SEE POTENTIAL PROBLEM WALK INTO DOOR AND NEAR SIGHTED LIKELY CAUSE LIKELY EFFECT BUMP HEAD PAIN TRIGGER PREVENTIVE ACTIONS CONTINGENT - ADAPTIVE -CORRECTIVE SURGERY GET GLASSES
2ND WHY CAN’T SEE POTENTIAL PROBLEM WALK INTO DOOR AND NEAR SIGHTED LIKELY CAUSE LIKELY EFFECT BUMP HEAD PAIN TRIGGER PREVENTIVE ACTIONS CONTINGENT - ADAPTIVE -CORRECTIVE SURGERY GET GLASSES
2ND WHY NEAR SIGHTED POTENTIAL PROBLEM CAN’T SEE WALK INTO DOOR AND LIKELY CAUSE LIKELY EFFECT TOO MUCH T.V. BUMP HEAD PAIN TRIGGER PREVENTIVE ACTIONS CONTINGENT - ADAPTIVE -CORRECTIVE SURGERY CUT OUT STAR TREK HAVE WE FOUND ROOT CAUSE?
2ND WHY NEAR SIGHTED POTENTIAL PROBLEM CAN’T SEE WALK INTO DOOR AND LIKELY CAUSE LIKELY EFFECT TOO MUCH T.V. BUMP HEAD PAIN TRIGGER PREVENTIVE ACTIONS CONTINGENT - ADAPTIVE -CORRECTIVE SURGERY CUT OUT STAR TREK OR GONE TOO FAR !
Determining Level of Analysis PRODUCT: SEAGATE DRIVE STXXXXX SUBSYSTEMS SPINDLE MOTOR DRAWING OR SPEC REFERENCE: DESIGN FMEA Oklahoma City SEVERITY OCCURRENCE EFFECTIVENESS S O E RPN PROCESS DESCRIPTION POTENTIAL POTENTIAL POTENTIAL CURRENT FAILURE MODE EFFECTS OF CAUSE(S) OF CONTROLS FUNCTION FAILURE FAILURE SPINDLE ROTATES NO SPIN, OR DRIVE RUNS DRIVE INOPERABLE FAILURE OF FLEX RESISTANCE MEDIA AT FIXED RPM IN REVERSE SOLDER JOINT DUE MEASUREMENT TO INSUFFICIENT AT INCOMING STRAIN RELIEF INSPECTION Here’s a Seagate Example Handbook pg. 43
Determining Level of Analysis PRODUCT: SEAGATE DRIVE STXXXXX SUBSYSTEMS SPINDLE MOTOR DRAWING OR SPEC REFERENCE: DESIGN FMEA Oklahoma City SEVERITY OCCURRENCE EFFECTIVENESS S O E RPN PROCESS DESCRIPTION POTENTIAL POTENTIAL POTENTIAL CURRENT FAILURE MODE EFFECTS OF CAUSE(S) OF CONTROLS FUNCTION FAILURE FAILURE SPINDLE ROTATES NO SPIN, OR DRIVE RUNS DRIVE INOPERABLE FAILURE OF FLEX RESISTANCE MEDIA AT FIXED RPM IN REVERSE SOLDER JOINT DUE MEASUREMENT TO INSUFFICIENT AT INCOMING STRAIN RELIEF INSPECTION Cause becomes Failure Mode Handbook pg. 43
Determining Level of Analysis PRODUCT: SEAGATE DRIVE STXXXXX SUBSYSTEMS SPINDLE MOTOR DRAWING OR SPEC REFERENCE: DESIGN FMEA Oklahoma City SEVERITY OCCURRENCE EFFECTIVENESS S O E RPN PROCESS DESCRIPTION POTENTIAL POTENTIAL POTENTIAL CURRENT FAILURE MODE EFFECTS OF CAUSE(S) OF CONTROLS FUNCTION FAILURE FAILURE SPINDLE ROTATES NO SPIN, OR DRIVE RUNS DRIVE INOPERABLE FAILURE OF FLEX RESISTANCE MEDIA AT FIXED RPM IN REVERSE SOLDER JOINT DUE MEASUREMENT TO INSUFFICIENT AT INCOMING STRAIN RELIEF INSPECTION Failure Mode becomes Effect Handbook pg. 43
Determining Level of Analysis PRODUCT: SEAGATE DRIVE STXXXXX SUBSYSTEMS SPINDLE MOTOR DRAWING OR SPEC REFERENCE: DESIGN FMEA Oklahoma City SEVERITY OCCURRENCE EFFECTIVENESS S O E RPN PROCESS DESCRIPTION POTENTIAL POTENTIAL POTENTIAL CURRENT FAILURE MODE EFFECTS OF CAUSE(S) OF CONTROLS FUNCTION FAILURE FAILURE WHY? SPINDLE ROTATES FAILURE OF FLEX SOLDER NO SPIN, OR DRIVE MEDIA AT FIXED RPM JOINT DUE TO RUNS IN REVERSE INSUFFICIENT STRAIN CAUSING DRIVE TO RELIEF BE INOPERABLE PROVIDES A DEEPER LEVEL OF ANALYSIS BY ASKING YOU FOR THE DESIGN CAUSES AND VERIFICATION OF INSUFFICIENT STRAIN RELIEF Handbook pg. 43
* What’s Wrong With This Picture? NUMBER OF PROCESS FAILURE CAUSES
* Actions A well-developed FMEA will be of limited value without positive and effective corrective actions. The design or process must be improved based on the results of the FMEA study.
Elements of FMEA Failure Mode Any way in which a process could could fail to meet some measurable expectation. Effect Assuming a failure does occur, describe the effects. List separately each main effect on both a downstream operation and the end user. Severity Using a scale provided, rate the seriousness of the effect. 10 represents worst case, 1 represents least severe. Causes This is the list of causes and/or potential causes of the failure mode. OccurrenceThis is a ranking, on a scale provided, of the likelihood of the failure occurring. 10 represents near certainty; 1 represents 6 sigma. In the case of a Six Sigma project, occurrence is generally derived from defect data. Current Controls All means of detecting the failure before product reaches the end user are listed under current controls. Effectiveness The effectiveness of each current control method is rated on a provided scale from 1 to 10. A 10 implies the control will not detect the presence of a failure; a 1 suggests detection is nearly certain.
FMEA is most effective when It is conducted on a timelybasis and It is applied by a product team and Its results are documented
Integrating FMEA into SOPs Example of how FMEA can be used in SCAR. Section of SCAR procedure FMEA can be used to identify the potential cause of failure and determine whether the current control is sufficient.
Link Tools Integration Tasks to Work Breakdown Structure The effort to integrate FMEA into SCAR procedures should be translated into specific tasks in the Work Breakdown Structure.
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