Failure Mode Identification in PFMEA according to AIAG FMEA Rev.4

Z

Zbigniew Huber

#1
Hi,

I?d like to ask you how to properly approach to identification of potential failure modes in PFMEA according to AIAG FMEA Rev.4.

Let?s consider brazing process of two pipes in air conditioning unit in a vehicle.

Approach 1:

Process step: 50. Brazing
Function: Braze pipes in induction device
Requirements: Solder alloy uniformly bonds both components with no cracks, pinholes or holes.
Failure mode: Holes in solder alloy
Effects: End user->Coolant leak, air conditioner non operable (6), Manufacturing->Scrap (7)
Severity: 7
Cause: Brazing time too short, incorrect setup program selected


Approach 2:

Process step: 50. Brazing
Function: Braze pipes in induction device
Requirements: Proper brazing time
Failure mode: Brazing time too short
Effects: Product effect: Holes in solder alloy, End user->Coolant leak, air conditioner non operable (6), Manufacturing->Scrap (7)
Severity: 7
Cause: Incorrect setup program selected

In my opinion the AIAG FMEA Rev.4 says Approach 1 is preferred due to following:

AIAG FMEA Rev.4 page 71:
The PFMEA development continues by identifying the requirement(s) for each process/function. Requirements are the outputs of each operation/step and relate to the requirements for the product. The Requirements provide a description of what should be achieved at each operation/step. The Requirements provide the team with a basis to identify potential failure modes.

AIAG FMEA Rev.4 page 112 (about linkage between PFMEA and Control Plan):
?Product Characteristics? portion of the Control Plan may be derived from the ?Requirements? portion of the ?Process Function/Requirements? column and the ?Process Characteristics? portion may be derived from the ?Potential Cause(s) of Failure Mode? column.

For me the requirements in the PFMEA are ?expected results? from the given operation (what we want to achieve when we complete the operation) and in the above example the product characteristic should be in the requirement for value added operations and process characteristic (brazing time) is related to the potential cause.

I understand that both approaches give similar results and someone could say that both are good, but I need to clarify this for a discussion with my colleagues and how to follow the AIAG FMEA manual.

Best Regards,
Zbigniew
 
Elsmar Forum Sponsor
#4
I cansee what you mean - in relation to page 71 in the manual.
But how is that related to page 81 with an example of requirements in the manual?
A bit ambigous - or is it just me?

Jan
 
G

Grimaskr

#5
I'm no expert, but these questions usually circle around "analysis depth".

You could take a "too high" analysis depth and say that a requirement of the brazing process is that the AC works or that the sealant doesn't leak. However, most people will agree that those failure modes are a little removed from where your focus needs to be during the brazing step itself.

You could also take a "too microscopic" analysis depth and say that a requirement of the brazing process is that brazing time is correct, brazing temperature is correct, brazing solder is correct, brazing solder is not expired, brazing equipment is functioning correctly... et cetera.

When you drill in too close, you can find yourself mired in many requirements and your FMEA becomes a bit of a nightmare.

So I agree with Approach 1, the requirement of the brazing process is a quality brazed joint. Failure mode is a "non-quality" brazed joint (holes/cracks), and the causes can be things like too little braze time.
 
Z

Zbigniew Huber

#6
I cansee what you mean - in relation to page 71 in the manual.
But how is that related to page 81 with an example of requirements in the manual?
A bit ambigous - or is it just me?

Jan
Maybe it is a bit ambiguous, that's why I ask

IMO, page 81 and page 71 have a same meaning.

The requirements in the example shown in page 81 are typical product related requirements (design intent / spec / drawing). Examples from p.81 are in black, my comments are in blue.

Four screws - it is design intent / drawing spec.
Specified screws - it is design intent / drawing spec.
Assembly sequence: - most likely it is also a design req. specified in engineering drawing
Screws fully seated: - it is design intent / drawing spec.
Screws torqued to dynamic torque specification - it is design intent / drawing spec.


Additionally please consider the following:

The failure mode when occurred is "experienced" by customers - it is called "effects". Customers in PFMEA are: next operation, next line, next factory, OEM, product end-user, law regulator.

So next operation (the closest customer) may only experience the "faulty outcome" (hole in solder joint) from the upstream operation. The customer can not experience incorrect process parameter of the upstream operation (i.e. too short brazing time), because the upstream process parameter no longer exists at customer location.
Only results of the upstream operation exist in downstream processes (customers) so the "faulty results" of the upstream operation are failure modes.

That is my understanding so far..

BR,
Zbigniew
 
Last edited by a moderator:
#7
I think you are right in how to interpret the requirements on page 81.
Thank you! That clarified a lot for me.

Regarding the effects, I am not sure if they will differ using one or the other approach.

Jan
 
Thread starter Similar threads Forum Replies Date
Y Design (DFMEA) and Process (PFMEA) FMEA Failure Mode Identification Design and Development of Products and Processes 8
C Failure mode at 0h, vs. 1 year vs. 5 year... FMEA and Control Plans 8
P Detection rating for a user (surgeon) related failure mode in DFMEA APQP and PPAP 3
N PFMEA Potential Failure Mode for Weight FMEA and Control Plans 5
A Failure Mode from Operator "Components Fallen but Loaded" FMEA and Control Plans 3
P UFMEA - Use Failure Mode Effects Analysis FMEA and Control Plans 7
Sean Kelley Seeking Feedback on ASQ Guide to Failure Mode and Effect Analysis FMEA and Control Plans 2
J Should failure mode caused by Fixture problem be into PFMEA? FMEA and Control Plans 2
T Would a Leak be a Failure Mode on a Design FMEA? Design and Development of Products and Processes 2
A Destructive Testing Failure Mode Sampling Plan Inspection, Prints (Drawings), Testing, Sampling and Related Topics 5
A FPA (Failure Prevention Analysis) and FMA (Failure Mode Avoidance) info wanted FMEA and Control Plans 6
G Relation b/n Process Failure Mode RPN Value and the associated Process Failure Cost FMEA and Control Plans 3
P Problem with "failure mode? interpretation in PFMEA (Process FMEA) FMEA and Control Plans 8
S Process Failure Mode Effects Analysis (PFMEA) Basics FMEA and Control Plans 4
S Basic PFMEA (Process Failure Mode Effects and Analysis) Questions FMEA and Control Plans 22
kedarg6500 Potential Failure Mode - Mix Charge for Hardness - Casting Process FMEA and Control Plans 1
N Definition Potential Failure Mode Definition and How to identify Failure Modes? Definitions, Acronyms, Abbreviations and Interpretations Listed Alphabetically 33
I Failure Mode help for Assembly Processes FMEA and Control Plans 8
M Difference between potential failure mode and potential effects of failure FMEA and Control Plans 11
W Plastic Part Painting/Spray Failure Mode - Sample PFMEA or control plan Manufacturing and Related Processes 7
W Potential Failure Mode - Machine Stroke not in specification FMEA and Control Plans 7
A Process FMEA - Help in deciding "detection ranking" of a failure mode FMEA and Control Plans 5
J DRBFM (Design Review Based on Failure Mode) - Toyota method Design and Development of Products and Processes 46
B How to demonstrate management commitment? Audit Failure Mode ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 4
A I have two doubts about PFMEA failure modes - How should I describe a "failure mode" FMEA and Control Plans 24
G Mechanical Failure as a Failure Mode in the PFMEA FMEA and Control Plans 28
Wes Bucey "Failure Mode Effect Analysis" 2nd Ed. by D.H. Stamatis Book, Video, Blog and Web Site Reviews and Recommendations 4
S Failure Mode SPC Statistical Analysis Tools, Techniques and SPC 10
H SFMEA - System Failure Mode Analysis FMEA and Control Plans 5
S Multiple controls for single failure mode FMEA and Control Plans 3
silentmonkey How to measure severity if my product is designed for emergency use and failure would result in death? ISO 14971 - Medical Device Risk Management 9
C Corrective action for failure in documents control ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 10
T Root Cause Failure Analysis - Not following Customer packaging Specification Problem Solving, Root Cause Fault and Failure Analysis 9
A Exact terms for a plating failure and difference between rejection rate and failure rate Manufacturing and Related Processes 9
JoCam Failure to test Class I medical device to IEC 60601-1-11 IEC 60601 - Medical Electrical Equipment Safety Standards Series 2
C Kaizen Events - Factors Affecting Failure Lean in Manufacturing and Service Industries 13
C Failure nets - Same level effects FMEA and Control Plans 0
R How to properly use Survival Analysis to predict time to machine failure Reliability Analysis - Predictions, Testing and Standards 0
D Testing to failure for design verification Reliability Analysis - Predictions, Testing and Standards 11
M Informational US FDA – Ethicon Recalls Circular Staplers for Insufficient Firing and Failure to Completely Form Staples Medical Device and FDA Regulations and Standards News 0
C Detection Action for Failure Effects - AIAG 4th Edition Layout FMEA and Control Plans 5
Marc NASA Says Oregon Company Metals Fraud Caused $700 Million Satellite Failure - 2019 World News 16
C PCBA Hardware Component different failure types - How to rate detection? FMEA and Control Plans 8
N PFMEA repetitive failure modes in subsecuent stations. FMEA and Control Plans 1
J How to look up Failure Modes on FDA website FMEA and Control Plans 4
P Electronic component failure analysis turnaround time Reliability Analysis - Predictions, Testing and Standards 0
C Design for Assembly in DFMEA - Failure Effect of Sub-System(s) FMEA and Control Plans 5
Marc Server RAM Failure - 7 Dec 2018 Forum News and General Information 3
K Spot weld - Peel test failure Manufacturing and Related Processes 3
C Electrical Power Plant Supply failure in PFMEAs FMEA and Control Plans 10

Similar threads

Top Bottom