Illegitimi non carborundum
Posted 22nd January 2009 at 04:06 AM by Howard Atkins
I wrote previously about GRR and having read the learned post Statistical process control for precision machining by bobdoering I was impressed by a number of issues.
I have always maintained that if you explain in a professional manner then customers will normally accept this and Bob gives support to my claim.
I used to work in a plastic injection molding company and a new project was starting with a very large tier 1. I went for a meeting with the buyer and the SQE at their headquarters and tried to explain to them that the requirements for continual SPC control over the critical dimensions were a meaningless objective. The point of SPC is to give an immediate indication to potential problems, as the plastic material shrinks over time the measurement will be or incorrect or to late for an indicator.
This seemed to be a very heretical idea as I explained that the requirement was irrelevant. They phoned their own plastic injection company and I was rewarded on their return to be told that all I had said had been confirmed.
As in the case of GRR Who are you cheating SPC is another tool that is blindly used with little understanding.
Some of the responsibility is on SQE's and Auditors who tell the company that they must do it.
The main problem though is with the manufacturing companies who do not properly understand their tools and if they do are not prepared to stand up for themselves.
Illegitimi_non_carborundum
"don't let the bastards grind you down".
Quote:
I have found that all customers (Big 3 and Japanese transplants) that I have trained on this concept (as a supplier) have accepted the concept, including its use for PPAP submissions.
I used to work in a plastic injection molding company and a new project was starting with a very large tier 1. I went for a meeting with the buyer and the SQE at their headquarters and tried to explain to them that the requirements for continual SPC control over the critical dimensions were a meaningless objective. The point of SPC is to give an immediate indication to potential problems, as the plastic material shrinks over time the measurement will be or incorrect or to late for an indicator.
This seemed to be a very heretical idea as I explained that the requirement was irrelevant. They phoned their own plastic injection company and I was rewarded on their return to be told that all I had said had been confirmed.
As in the case of GRR Who are you cheating SPC is another tool that is blindly used with little understanding.
Some of the responsibility is on SQE's and Auditors who tell the company that they must do it.
The main problem though is with the manufacturing companies who do not properly understand their tools and if they do are not prepared to stand up for themselves.
Illegitimi_non_carborundum"don't let the bastards grind you down".
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