Are all Bias, Linearity, GRR and Stability to be performed for equipment defined in Control Plan?

Please enlighten me as follows:
1. Is it true that the equipment defined in Control Plan must be done Bias, Linearity, GRR and Stability completely without exemption?

2. If there are several equipment with the same brand/model, can we do Bias, Linearity, GRR and Stability for only 1 equipment as representative?

I could not find this in AIAG MSA Manual, please advise.

 

A few years ago we had a finding for no Bias, etc. We only did a GR&R.

My understanding is you can use only one of the same instruments as a representative sample.

 

Andy, is it nonconformance if the stability is not done?
It is very difficult for me to debate with any customer/auditor, which manual should be used for reference to select proper MSA method to be done?

In my opinion, Bias, Linearity, GR&R should be done but Stability may or may not be done depending on sensitivity of equipment.
Correct me if my opinion is not valid.

 

In my work place, we only do Gage R&R for all the measuring equipement in CP. I also wonder why there is no bias, linear, stability studies. However for your reference, no NC was raised during 2nd and 3rd QMS audits. Maybe it is due to the position where my company is in the automotive supplier chain. We are far from the OEMs.

 

Judegu, this is the reason why I need to know what is right what is wrong and the reason. Auditor and customer might not be clear and ask for unnecessary thing but we should have clear explanation to them.
I am waiting for the clear answer from Guru.

 

I am not sure about the Auditors` competence on determinging which is right or wrong regarding the MSA. What I do know is that some of the customers don`t know it quite well. They only got very vague understanding on MSA as I do. In my workplace It looks like that we only do the Gage R&R as it is a requirement from the Automotive Standard. Does it(MSA) do any good to the whole process in our company? Highly doubtful.

 

Hi Bev D, your answer is reasonable. I wonder why AIAG MSA Manual written is such way that the reader has difficulty to understand and interprete. Different person has different interpretation causing an argument especially customer and supplier. You should be AIAG member.

 

Hello Miner, many thanks, will read through your articles.

 

The reason the manuals are written the way they are is that the OEMs would never agree to wording that prevents them from asking for more information. They can be summed up in this sentence:

"We all agree you should do things this way, however, we reserve the right to ask for more ..."

It is worded this way because there may come a day when a customer legitimately DOES need more and you don't want an unreasonable supplier using the (arbitrary) blue books as a defense to not have to do the right thing.

This creates the inherent weakness in the system - when someone is in a decision making position that does not understand the requirements, they generally default to a position of asking for "stuff" until it feels right. They don't pay for the extra work, after all, and they don't want their organization to know they may need more training. Which creates this busy work we all as suppliers sometimes face.

We then have to make the decision - is it more cost effective to fight it? Or just comply (which while cheaper, in the long run, reinforces the bad decisions).

I have found the best way to defend against these unreasonable requests is with good internal standards. If a supplier quality engineer is asking you for extra, nonsensical things and you can produce a logical, active, QMS controlled standard that appears to be followed, your defense is then "Well, you're asking me to change our standard way of working - we don't do that lightly ..." That can often calm them down ...