Seminar Report
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Transcript of Seminar Report
Function:Function of the item being analyzed to meet the Design intent. Includes information regarding the environment in which this
system operates.Failure Mode:
A ‘Failure Mode’ is the manner in which a component, assembly or system could potentially fail to meet the design intent. Typical failure mode may include, not limited to:
Yield; Fatigue; Material Instability; creep; wear; corrosion; Cracked Deformed; Leaking
What is FMEA?FMEA is a systemised group of activities to:•Recognise and evaluate the potential failure of a product / process and its effects•Identify actions which could eliminate or reduce the chance of potential failure occurring•Document the process
Why FMEA?•For a company policy where continuous improvement is emphasized for its product, process•FMEA is a living document
Who should do FMEA?•Cross Functional Team Effort – with a leader•Team of knowledgeable individuals Ex. Expertise in Design, Mfg., Assly, Quality. Etc.•Team should include representatives of sub-contractors and/or customers
QS-9000 requirements•FMEA shall consider special characteristics•Aiming defect prevention rather than defect detection•Use FMEA manual & CFT approach
When FMEA should be done?Essence is timeliness•Pro-Active rather than reactive•Before process failure mode occursAdvantages of FMEA•Avoids late change crisis•Reduces or eliminates chance of implementing corrective change•excellent technique for preventive action•interactive process which is never ending
Process
Function/ Requirements
Potential Failure Mode
Potential Effect(s) of Failure
Specify the description and Function of the process
List out Outputs of the Process
ExampleProcess function / description
- Manual application of wax inside door- Machining of outer diameterRequirements- To cover inner door at minimum thickness to
retard corrosion- Outer diameter, run-out, free from tool mark
Potential Failure Mode Potential Effect(s) of Failure
Sev
Two Assumptions are1. Consider all inputs are acceptable2. Consider the Design is acceptable List the failure modes those are possible to occur
against the requirements specified in the previous column.
Apart from Engg. Specification, what would a customer consider objectionable
CUSTOMER is- Next opn.- Subsequent Opn.- End user ExampleBent, Diameter oversize, Diameter undersize, Cracked, Deformed, Open Circuited, BurredOD not clear – Is it a failure mode in machining of casting / forging?
Potential Effect(s) of Failure Sev Class List the effects of failure in- Next operation- Subsequent operations- Customer- End user/ Environment Describe the effects using the terminology specified in Severity
rating table For each failure mode, more than one effect can be listed
Severity
Class
Potential Cause(s) / Mechanism (s) of Failure
Assess the seriousness of the effect in a 1-10 scale
This rating applies to EFFECT only (i.e. previous column)
Consider the Design FMEA Consult subsequent Mfg./ Assembly
plant Safety related effects should be rated in
Nos.9 or 10 While giving ranking consider only the
required criteria (i.e. next opn. / vehicle)
ClassificationPotential Cause(s) /
Mechanism (s) of Failure
Occur
Classify special product characteristics (e.g. critical, key, major)
Potential Cause(s) / Mechanism (s) of Failure Occur
Current Process Control
prevention
Current Process Control
detection
List the first level potential causes such as - man- machine- tool- process parameter- Fixture etc. List the root causes under the first level causes using
WHY? WHY? analysis Describe the causes in such a way that can be eliminated
or controlled Don’t use ambiguous statements such as - operator mal-functioning- Fixture problem etc. Use the cause and effect diagram, if required consider input materials in last iteration of cause analysis
Contd.….
Occurrence
Current Process Controls
prevention
Current Process
Controls
Detection
Estimate the probability of occurrence on a 1-10 scale
Rate against each causes Use past data as a basis (cpk/rejection %) for
ranking Document the basis of occurrence ranking For a new process, if there is no previous
experience, use team judgementDon’t consider failure-detecting measures while giving ranking (100% inspection.)
Current Process Control
Prevention
Current Process Control
Detection
Detect
RPN
Type of Controls
Level Type Examples
P-Prevention Prevention of causes Mistake proofing
D- Detection
Detection of causes & leading to corrective actions Detection of defect
SPC, Visual control etc. 100% inspection, patrol inspection
List the existing controls, which can detect the causes or failure mode While listing, specify the frequency of detection measures
Examples
- Visual Check, one per shift for film thickness - SPC chart five pieces in an hour - On-line monitoring of crimping force - Auto-control of temperature - 100% on-line inspection - Visual monitoring of Ammeter
Detection RPN Recommended Action
Assess the probability of controls listed in the previous column, which will detect the cause or failure mode
While giving ranking, assume the failure is occurred Don’t assume ranking is low because the occurrence is
low Random controls should not influence detection
ranking One detection ranking can be assigned to multiple
controls
Recommended Action
Responsibility
& Target Completion Date
Action Results
Policy for RPN to take action - Define a target RPN and anything above that can be
considered for action. For Ex. It can be 50. Considering 95% of the failures are attended
- consider only high priority no. for take action and review periodically
As a first priority, take action on causes to reduce occurrence ranking
The next priority is to consider action on controls to reduce detection ranking
severity ranking can be reduced by - elimination of failure mode by change in processes or
design
Responsibility & Target Completion DateActions Taken
SevOcc
De t
RPN
Specify the responsibility and target completion date for every actions identified
During APQP, the FMEA completion dates should be prior to Production run
PROCESS FMEA QUALITY OBJECTIVES•PROCESS IMPROVEMENTS: The FMEA drives process improvement as primary objective. With an emphasis on Error / Mistake proofing solutions •HIGH RISK FAILURE MODES: The FMEA address all high-risk failure modes as identified by FMEA team, with executable action plans. All other failure modes are considered. •CONTROL PLANS: The pre launch and production Control Plan consider the failure modes from the process FMEA. •INTEGRATION: The FMEA is integrated and consistent with process flow diagram and the process control plan. The process FMEA considers the design FMEA, if available as part of its analysis. •LESSONS LEARNED: The FMEA considered all major “ lessons learned “ as input to failure mode identification •SPECIAL OR KEY CHARACTERISTICS: The FMEA identifies appropriate key characteristics candidates as input to the key characteristics selection process, if applicable due to company policy. •TIMING: The FMEA is completed during the “Window of opportunity “where it could most efficiently impact the product design of product or process.•TEAM: The right people participate as part of the FMEA team throughout the analysis and are adequately trained in FMEA methods •DOCUMENTATION: The FMEA is completely filled out “by the book” including “action plan” and new RPN values.•TIME USAGE: Time spent by FMEA team as early as possible is an effective & efficient use of time, with a value –added result. This assumes recommended actions are identified as required and the actions are implemented.
Action Results
Actions Taken Sev Occ Det RPN
Describe the verification results Where effectiveness measure is required, specify
the target date accordingly After the assessment of the actions taken, re-
assess the values of severity, occurrence, detection and RPN