Fmea process la

Potential Failure Mode & Effects Analysis FMEA

PROCESS FMEA

ISO TS 16949:2002 Lead Auditor Course

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Course Objectives

• By the end of the course the participant should be able to;– Understand how to audit FMEA’s

process identify the two types of FMEA’s complete a Process FMEA for a project understand how to determine the RPN

and its implication

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Failure Mode and Effects Analysis

• ISO TS requires FMEA’s to be generated and revised during the following stages;– Advanced Product Quality Planning - before or at

design concept finalisation/prior to tooling for production

– Design reviews

– As a result of customer complaints

– As as result of customer/field returns

• FMEA’s are LIVING DOCUMENTS

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• What is an FMEA?– An FMEA is a structured process used to

analyse design and/or process activities and to assure that potential failure modes have been addressed and effects analysed.

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• An FMEA is a team process not a single person process

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• Benefits of FMEA’s

– 1. Utilises previous history and associated failure modes

to assist in developing quality products during

design - better understanding of the product

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– 2. An objective evaluation of the design or process - not

subjective. It forces an organisation to quantify

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– 3. Cost & time savings - The process identifies potential

causes/mechanisms of failure before they occur

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– 4. Provides a system for establishing design and process improvements and for identifying Special

Characteristics

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• 5. A structured proactive system that aims to provide for Customer Satisfaction

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• There are two types of FMEA’s

• 1. Design FMEA– Cooling system for vehicle, spoiler assembly,

wiring harness etc..

• 2. Process FMEA– Injection moulding, welding, assembling etc...

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• Definition of a Design FMEA– A design FMEA is a structured process

used by Design Responsible companies to ensure, to the extent possible, that possible failure modes and their associated causes and mechanisms have been considered during the design process.

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Failure Mode and Effects Analysis• Examples of when Design FMEA’s may be used;

– A company may be responsible for the complete design of the cooling system of a vehicle.

– A company may be responsible for designing a complete trimmed seat assembly

– A company may be responsible for developing and designing a material to reduce Noise and Vibration in a vehicle

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• Definition of a Process FMEA– A process FMEA is a structured process

used by a manufacturing company to identify potential failure modes and their associated causes and mechanisms for the manufacture and assembly of product.

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• Examples of when Process FMEA’s may be used;– A company has been provided with all of

the technical information to manufacture; • An injection moulded interior door handle

• A metal pressed bracket

• A family of fasteners

How to Complete aProcess FMEA

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Process Failure Mode and Effects Analysis

• How to complete a Process FMEA1. FMEA number

• A number used for tracking and identifying the Process FMEA

– GM -001A

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– How to complete a Process FMEA

2. Item• Enter the name and number of the system, sub-system

or component for which the process is being analysed

– Rear Decklid Spoiler 92078645

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3. Process Responsibility• Indicate the OEM, department and/or group

which is responsible for the Process

– Spoiler Design Team

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4. Prepared by:• Enter the contact details of the person

responsible for preparing the Process FMEA. This is typically the Process/Product Engineer

– Max Smart

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5. Model Year(s)/Vehicle(s)• Enter the intended model year(s) and vehicle

lines that will utilise and/or be affected by the Process being analysed, if known

– WH 1999

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6. Key Date• The key date is defined as the due date for the

Process FMEA. This date should not exceed the scheduled start of production.

– July 1999

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7. FMEA Date• This date is defined as the original date the

Process FMEA was compiled and the latest revision date.

– June 5, 1998, August 10, 1999 Rev 8

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8. Core Team• List the names of the responsible individuals

and departments who have participated in the generation of the Process FMEA.

– AW, PS, JA, RK, MH

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9. Process/Function Requirements• Enter the name of the process being analysed.

It is important to be as concise as possible. Use the same terminology as per any reference documents.

• Examples are;

trimming, vacuum forming, welding etc..

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10. Potential Failure Mode• Enter the potential failure mode(s) for that

process. Examples of failure modes might be, but are not limited to;

– Stressing, Burrs, Cracking, Burning, Flash, Fails to open, Part leaking, bent, brittle, worn, tool mark etc...

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11. Potential Effects of Failure• What if the failure occurs, what are the potential

effects? These need to be written from the customers perspective. This can mean the next operation or machine, not just end customer.

• Examples

• inoperable, unsatisfactory appearance, noisy because of vibration, uncomfortable, erratic operation, unable to fit or locate etc...

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12. Severity• Enter the severity rating as described in

Appendix 1. The severity is an assessment of the seriousness of the problem

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13. Classification• Enter the special characteristic symbol as per

customer requirements for any critical, significant, major, safety or Key characteristic. ISO TS Section II should define the type of symbol required.

ISO TS requires that all special characteristics are addressed during the FMEA stage.

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14. Potential Cause(s)/Mechanism(s) of Failure

• Enter any potential reasons for these failures– Examples are:

– Improper weld

– Part not mounted correctly before drilling

– Incorrect cycle time

– Inadequate gauging

– Human error, Fatigue, interaction..

– Tool worn

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15. Occurrence– Enter the Occurrence as per Appendix 2.

The Occurrence is defined is the probability or the likelihood that the specific cause or mechanism will occur. This may be based on previous field history, similar products and experience

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16. Current Process Controls• Enter the current Process

verification/validation activities that will assure the adequacy of the Process

• Typical examples may be, SPC, gauging

error proofing etc...

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17. Detection• Enter the detection probability as per Appendix

3. Detection is defined as the ability of the proposed Process controls to detect any Process weakness or potential failure.

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18. Risk Priority Number (RPN)• The Risk Priority Number is defined as the

Severity multiplied by the Occurrence multiplied by the Detection. The RPN is a measure of the Process risk. The RPN will be between 1 and 1000. It is the responsibility of the group to define what a high RPN is and take the appropriate actions.

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19. Recommended Action(s)• When high RPN’s are established corrective

action should be incorporated with a focus on reducing the Process risk

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20. Responsibility• Enter the name of the person(s) or organisation

who has the responsibility for implementing the corrective action(s). This should also include a target date for completion.

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21. Actions taken• Enter the effectiveness and the results of the

actions taken

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22. Severity• Re-enter the severity rating as described in

Appendix 1. The severity is an assessment of the seriousness of the problem.

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23. Occurrence• Re-enter the Occurrence as per Appendix 2.

The Occurrence is defined as the probability or the likelihood that the specific cause or mechanism of failure will occur. This may be based on previous field history, similar products and/or experience.

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24. Detection• Re-enter the Detection probability as per

Appendix 3. Detection is defined as the ability of the proposed Process controls to detect any Process weakness or potential failure.

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25. Resulting RPN• Based on the corrective action, calculate the

RPN and record this result. If further action is required repeat the corrective action steps in order to reduce the RPN.

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Appendix 1 Severity rating for Process FMEAEffect Customer Effect Manufacturing/ Assembly Effect Ranking

Hazardous-without warning

Very high severity ranking when a potential failure mode affects safe vehicle operation and/or involves nonconpliance with government regulation without warning.

Or may endanger machine or assembly operator, without warning.

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Hazardous with

warning

Very high severity ranking when a potential failure mode affects safe vehicle operation and/or involves nonconpliance with government regulation without warning

Or may endanger machine or assembly operator, with warning

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Very High Vehicle/item is inoperable, loss of primary function

Or 100% of product may have to be scrapped, or vehicle/item repaired in repair dept with a repair time greater then 1 hr

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High Vehicle/item is operable, but at a reduced level of performance. Customer very dissatisfied.

Or product may have to be sorted and a portion (less than 100%) scrapped, oer vehicle/item repaired in the repair department with a repair time between a half hour to one hour.

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Moderate Vehicle/item is operable, but comfort/convenience items inoperbale. Customer dissatisfied

Or a portion (less than 100%) of the product may have to be scrapped with no sorting, or vehicle/item repaired in repair department with a repair time of less then 1 hour

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Low Vehicle/item is operable, but comfort/convenience items operbale at a reduced level of performance

Or 100% of product may have to be reworked, or vehicle item repaired off line but does not fo to repair dept

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Very low Fit and finish/squeak and rattle item does not conform. Defect noticed by most customers (greater then 75%)

Or the product may have to be sorted, with no scrap, and a portion(less then 100%) scrapped.

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Minor Fit and finish/squeak and rattle item does not conform. Defect noticed by 50% customers.

Or a portion (less then 100%) of the product may have to be reworked with no scrap, on line but out of station.

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Very Minor Fit and finish/squeak and rattle item does not conform. Defect noticed bydiscriminating customers (less then 25%)

Or a portion (less then 100%) of the product may have to be reworked with no scrap, on line but in station.

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None No discernable effect. Or slight inconvenience to operation or operator, or no effect

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Appendix 2Occurrence rating for Process FMEA

Probability of failure Possible failure rates Ppk Ranking

Very High - Persistent failures ≥ 100 per thousand pieces < 0.55 10

50 per thousand pieces ≥ 0.55 9High - Frequent failures 20 per thousand pieces ≥ 0.78 8

10 per thousand pieces ≥ 0.86 7Moderate - Occasional Failures 5 per thousand pieces ≥ 0.94 6

2 per thousand pieces ≥ 1.00 51 per thousand pieces ≥ 1.10 4

Low - Isolated failures associated with similar processes

0.5 per thousand pieces ≥ 1.20 3

Low - Relatively few failures 0.1 per thousand pieces ≥ 1.30 2

Remote - Failure is unlikely. ≤ 0.01 per thousand pieces ≥ 1.67 1

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Appendix 3Detection rating for Process FMEA

Detection Criteria Suggested Range of Detection Methods

Ranking

A B C

Almost impossible

Absolute certainty of non-detection

X Cannot detect or is not checked 10

Very remote Controls will probably not detect

X Control is achieved with indirect or random checks only

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Remote Controls have poor chance of detection

X Control is achieved with visual inspection only

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Very Low Controls have poor chance of detection

X Control is achieved with double visual inspection only

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Low Controls may detect

X X Control is achieved with SPC charting methods

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Moderate Controls may detect

X Control is based on variable gauging after parts have left the station, or GO/NO GO gauging performed on 100% of the parts after the parts have left the station

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Moderately High

Controls have a good chance to detect

X X Error detection in subsequent operations, OR gauging performed on setup and first piece check

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High Controls have a good chance to detect

X X Error detection in station, or detection in subsequent operations by multiple layers of acceptance: supply, inspect, install and verify. Cannot accept discrepant part.

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Very High Controls almost certain to detect

X X Error detection in-station (automatic gauging with automatic stop feature). Cannot pass discrepant part.

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Very High Controls certain to detect

X Discrepant parts cannot be made because item has been error-proofed by process/product design

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Inspection Types

Inspection types

A = Error proofedB = GaugingC = Manual Inspection

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Auditing PFMEA’s

1. Is the PFMEA conducted by a cross functional team?

2. Has the Key date been defined

3. Is it consistent with the customer’s PPAP date?

4. Does the organisation consider all of the elements within the process flow chart?

5. Has the organisation defined what constitutes a high RPN

6. Does the organisation follow the definition of a high RPN

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Auditing PFMEA’s

7. Are recommended actions completed prior to the Key date

8. Do the sequence of dates make sense?

9. How are revisions recorded?

10. Does the organisation ensure the PFMEA is a living document?

11. Verify the occurrence rankings are based on objective evidence

12. Ensure the organisation is using the correct rankings for Severity, Occurrence and Detection

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