Control Method correspondence between PFMEA and CP

#1
Hi everyone, I am looking forward for your input.

It is said (as per AIAG) that there should be correspondence between the PFMEA and CP in regards of the "control methods" for all characteristics (which has failure modes, effects and causes associated).

Before expressing my approach, I want to set the following assumptions:

a) Controls should be planned in the PFMEA in order to prevent ("ocurrence") and to detect ("detection") failures modes and/or their causes. With this, we pursue to keep ocurrence and detection ability in an aceptable level in accordance with "severity".
b) All Control Plans I have seen in the past only include one control, typically for detection and in few cases for prevention when there are poka-yokes involved.

My approach is that every characteristic in the CP should include both control methods (prevention/detection) defined in the PFMEA.


Please give me your point of view about what I am right and what I am wrong, since I have not found any compelling answer from customer representatives or consultants.

Best Regards
 

Sebastian

Involved - Posts
#2
Dear Mario,
there are three sources of requirements related to control plan content: AIAG APQP and Control Plan manual, IATF 16949 standard and Customer Specific Requirements. Unfortunately requirements are not "synchronised" so it is organization's job to satisfy all of them.
IATF 16949 section 8.5.1.1 says:
The organization shall have a control plan for pre-launch and production that shows linkage and incorporates information from the design risk analysis (if provided by the customer), process flow diagram, and manufacturing process risk analysis outputs (such as FMEA).
So literary not only PFMEA outputs shall be included in control, but also DFMEA. Only one thing I do not understand is why only when provided by customer when organization can be design responsible and therefore performs own design risk analysis.

All detection (no matter prevention/detection) activities who were listed in PFMEA as "in place" shall be transferred into control plan. Control plan shall be updated also with all recommended actions related to detection activities, when they are in place.
Regarding prevention, frequency of verification of error proofing methods shall be included in control plan, this is all as specified by IATF 16949 standard section 10.2.4.

I have seen not so much organizational control plans, but generally, what I've seen is not so encouraging. In most cases control plan were limited only to activities performed by humans. Manufacturing machine embedded steering systems, who control process parameters during every cycle were not mentioned there.

In my opinion your understanding is correct, but as long it is not literary written in manuals or standard, organizations will create control plans as they want.
 
#3
Thank you Sebastian

I guess it should suffice if the control plan references at leats one of the two controls listed in PFMEA (detection/prevention) for each characteristic, we would be in non-compliance if the control is another different than any of those stated in PFMEA.

In practical terms it does not have sense to me if we do not reference all controls defined, so we are putting aside some valuable controls that are not assured to be implemented and audited as they are not present in the CP.

Regards
 

Sebastian

Involved - Posts
#4
IATF 16949 section 9.1.1.1 says:
[...]The organization shall verify that the process flow diagram, PFMEA, and control plan are implemented[...]
Some might say it is clear evidence that not all detection methods from PFMEA shall be in transferred into control plan. I would say, that IATF is aware of poor quality of control plans and assign e.g. internal auditors to detect discrepancies between line conditions and these three documents. By the way PFMEA is a new element here comparing to ISO/TS 16949 section 8.2.3.1.
 

paccnc

Starting to get Involved
#5
Hi Mario, I hope you don't mind but I want to piggy back a question regarding control plans and error-proofing methods. We received a minor N/C for our control plans because we didn't list our error-proofing methods on the control plan per Annex A in the IATF 16949 Standard under Methods item b) error-proofing. I was interested in how other people are addressing this item? Thank you in advance for your assistance.
 

Sebastian

Involved - Posts
#6
Did you have it in PFMEA? If yes, so copy information from PFMEA "Requirement" column into Control Plan "Characteristic" (product or process).
Then copy information from PFMEA "Prevention" column into Control Plan "Control Method".
Does this answer your question?
 

paccnc

Starting to get Involved
#7
We didn't have it listed in the PFMEA. What the finding was is that we use a feed sensor and part out sensor on our die. When we set the job up our operators set up these sensors. We didn't have them listed on our control plan as an error proofing method. So I don't need to add a complete new column on the control plan called Error roofing, I just need to list it in the Control Method and list it as error proofing, correct?
 
#8
Paccnc

There are some questions that need to be answered.

1. Does that error proofing help to prevent any failure mode you have defined in your PFMEA?
2. If so, what is the current control you have declared in the "Control Method" column in your control plan for the characteristic associated to that failure mode?

For example:
If your failure mode in PFMEA is: wrong nut assembled
The associated product characteristic in the CP may be: correct nut 9/16"
The control method column in the CP may be: inspection, measuring, error proofing, etc.
 
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