Manufacturing Process Changes (7.1.4)

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rui12524

Being this item under “Planning of product realization”, I would understand this “shall” applied to manufacturing process changes if it was under 7.3 (7.3.7 to be exact). It seems to me that the intent is that we must be prepared (have pre-defined actions to do) in case of “changes” that affect product realization. How can I apply this to an injection moulding process? The “changes” happen every time I do a new job (new lot of material, different machine, etc.); my opinion is that we must decide what is a “change” in our manufacturing process. Your thoughts are welcome.
 
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Roger Eastin

I think you hit it on the head! YOU define what a process change is and then apply the process change requirements. This requirement will get ridiculous if a change is defined every time some one "tweeks" the process. Give yourself some latitude. There is another side to this, though. This requirement will help you control the "over-adjusters" in your operation. Over-adjusting can cost the company money by introducing change when it is NOT needed. This can casue excess variation to your process which can cost you money. My advice is to define it realistically, but use it to your advantage to control variation.
 
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Sam

I agree with Roger. It's no coincidence that "over-adjustment" is one of the basic statiscal concepts to be known ahd understood through the organization.
IMO para 7.1.4 requires you to have a full understanding of the process, in order that you might prevent the tweaking or over-adjustment by the operator or set-up personnel.
 
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Bill Ryan - 2007

I work for a die cast/machine house. One way we have addressed the "different machine" issue (we have 25 machines with varying tonnage classifications up to 900 ton) is by submitting PPAP from the lowest rated machine the die will perform on. Many studies have proven no degradation in product quality by moving the tool to a higher classification of machine - in fact, we can typically improve the quality through differing capabilities of monitoring the shot end.

I can't really address the differing raw material lots except that your supplier should (read "shall") be capable of meeting the material specifications on a lot to lot basis. We alloy our own metal, control it coming out of our Central Melt furnace and monitor metal chemistry in the holding furnaces. When we have the need for a "special" alloy, we buy only from a certified source (whatever that gets us) and then perform random audits on the lots of Ingot.

I completely agree with Roger and Sam concerning you deciding what is a process change and what isn't (however, don't be surprised if your SQA decides to "help" you with your definition). I might be all wet but as I look at the requirement, it is saying that should something in your process change which causes a quality concern, how do you handle the issue? We have a corporate nonconforming material procedure which is supposed to cover any parameter "tweaking". We encourage our operators to experiment (with guidance!!!!) but when experimenting, product must have an NCM tag.

I think I'm getting off base here so I'll sign off. Hope this helps some.

Bill
 
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