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Special Vs Non-Special Processes

I've been looking for easy and simple way to assess Special Vs Non-Special processes for validation purpose. I don't simply want to depend upon what manufacturing engineer tells me. Is reading their mfg procedure or walk through the Mfg process itself would benefit? please help.

Sidney Vianna

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Your question is not clear. Are you asking how to determine if a process should be considered "special" and be validated?

Or are you asking how to determine the validation of special processes?

Have you looked at the "similar discussion threads"? scroll down.
I'm asking for the easy way or tools to assess the mfg processes and sub-processes to see if they are special, hence I can perform the validation. I'm not worried about how to perform validation part. Thank you.

Sidney Vianna

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There is no "easy" method.

You have to assess what are the critical characteristics of the products after the processes and ascertain if you can determine by examination if such characteristics are achieved or not, without a destructive test.

If you can't, very likely, you have to control process parameters which have demonstrated (by validation, including destructive testing) that results in conforming product.

One must have a good understanding of the product, application, context, materials and production processes to determine if the process needs validation or not.
If the only way to see if something turned out correctly is with destructive testing then it is clearly a special process.

If it can be determined with inspection or test, but the inspection or test isn't economically feasible, you should consider it as a special process.

There can be other factors to consider as well, but the one that fall into the two above categories should be clear and you should start with them.

The poster child list for special processes include welding, brazing, soldering, heat treating, and plating. Often other coatings and painting fall into that category.

This is not an exhaustive list.


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OK, but what about the fact that the inspection itself is considered special process? - see NADCAP...:(
A process can be a special process....but inspection of a process can be a special process too?? That doesnt fit the definition, because the inspection cannot be inspected etc...
That confuses me.

Sidney Vianna

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Why are you still referring to the 2008 edition? There is a REQUIREMENT in 9001 that certain processes need to be validated and re-validated. Most Non Destructive Examinations have to be performed by specially qualified personnel, using specialized equipment and following specialized methods. That screams validation. Try doing an X-ray testing without any training, for example. Not only you will not accomplish the end goal, but might getting yourself exposed to nocive radiation from a radioactive source. Without a question, most NDT processes need to be validated, due to their nature and characteristics. If you have a specific example you want to discuss, bring it up for discussion.
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