Masking Fixtures - Nadcap Audit Requirements

Posted by: GeneralDisarray

Masking Fixtures - Nadcap Audit Requirements - 04/19/21 04:33 AM

Hi, this is my first post, I've been silently reading in the shadows smile

We don't currently hold Nadcap accreditation for Shot Peening but we do hold it for other processes with an intent to achieve AC7117 approval within the next 12 months.

An internal auditor has flagged our masking of holes in terms of AC7117 4.1.2.

We use rubber bungs to mask holes. would these be considered a 'fixture' - requiring inspection pre-peening? (Our customer has no requirement, just compliance with AMS2430)

My interpretation is that AMS2430 Table 3 specifies individual items for Masking Fixture and Part Masking... A 'Masking Fixture' (Baffle) would require routine inspection but part masking (bungs/tape) don't.

Or would we be better off just adding standard text to our route card "Ensure that masking bungs are of a satisfactory condition prior to peening".

Many Thanks if you've read this far, I don't have anyone else to ask.

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AC7117:

*Is there objective evidence that the Supplier checks the physical characteristics of masking fixtures in accordance with a maintenance or calibration plan?
Compliance Assessment Guidance: NA substantiation – Where no masking fixture is used by peening Supplier.

Staff Engineers Handbook:

4.1.2 Visually check the condition of the masking and check parts for effectiveness of the masking, some Customers specify the required magnification level for inspection. There is documented evidence that the inspection and/or verification has been performed. Example: Setup sign off is acceptable, if the setup includes this inspection.
Posted by: Walter

Re: Masking Fixtures - Nadcap Audit Requirements - 04/19/21 06:00 AM

I believe your interpretation is correct. Plugs and tape are not fixtures. I would suggest having a standard instruction step(s) to inspect the first part prior to peening and after peening. This will insure the part masked correctly and it is effective.