Paint finish rejections

[Jim Wynne]

The only specs that cover cleaning are for the primer. I guess without knowing if the FOD is under or over the primer, the entire lot could be rejected based upon the specs on the primer alone.

MIL-PRF23377 is a standard for manufacturing the primer, not for its end use. FED-STD-595 is for color specification, and doesn't seem applicable at all to your situation. It looks like someone did a poor job of identifying relevant standards.

 

[gjkoenig]

Thank you, that concurs to what I have been saying.

 

[Jim Wynne]

Thank you, that concurs to what I have been saying.

Once a thread has several participants, it's important to quote the post you're replying to. In this case, we don't know what "...that concurs..." refers to. You can quote the post you're replying to by clicking on the "Reply to..." button:

 

[Marc]

The rejections are for some marks on the paint that expose the primer and for FOD/dust specs under the paint. Not every part has this issue but the entire lot is rejected. The question is to what can we use to hold our supplier accountable to for the paint?

First, contact the supplier and discuss the issue. Exposed primer and FOD/dust under the paint are common issues that even if not specified in the contract are standard 'understood' nonconformances. If they have any credibility they're not going to argue. Whether you reject the lot or not is an issue, but it will come down to who does the sort, and where, and who bears the cost of the sort, assuming all are not bad.

My opinion is based upon a number of years of working with companies in resolving cosmetic issues, from paint(s) to screen printing to anodize, of metal, injection molded and parts of other materials.

I remember a problem with a Honda part in one company which argued that the defects ('pinpoints' of exposed primer, mainly) were on a cover for an engine part where the the defect(s) were on the inside where the end user would never even see them. Honda would not yield - Their position was a defect is a defect and there was no exception just because the area would never be seen.

Typically boundary samples are used for determination of accept/reject.

 

[Marc]

FYI - I knew I had this somewhere. This is a surface finish 'ruler' I made up in the 1990's. It was a small plastic ruler that could be used by inspectors to address surface defect issues. Typically surface cosmetic requirement(s) are addressed during initial contract review - Sometimes there are agreed upon allowances for some surface defects.



While a bit off topic, things to think about:

• In color issues, you may need a Macbeth booth. E.g.: X-Rite (Macbeth) SpectraLight QC Viewing Booth
• In surface roughness issues, you may need a surface roughness meter. E.g.: Surface Roughness Meter - Surface Roughness Meter TIME 3220 Manufacturer from Ahmedabad
• For grained surfaces, I recommend boundary samples.
• For surface 'gloss', consider a gloss meter. - Glossmeter - Wikipedia

Misc: Eliminate Surface Defects on Molded Parts

The links above are from a search I did and are not endorsements of any company product(s) and/or service(s).

 

[gjkoenig]

MIL-PRF23377 is a standard for manufacturing the primer, not for its end use. FED-STD-595 is for color specification, and doesn't seem applicable at all to your situation. It looks like someone did a poor job of identifying relevant standards.

Thank you, that concurs to what I have been saying.

 

[AndyN]

With the parts now back in my lap, myself and the purchasing team are put on the spot to come up with a reason for rejection to the supplier.

I'd put your sales/marketing person on the spot to make a decision...