Can you deviate from a mil standard? 4

[Spoolx]

Hi all,
I ran across something today and wanted to get other engineers opinions.

I design products for a company and we routinely use mil specs to identify process parameters for our products.

Recently, I released a drawing that said process per the anodize mil-spec-xxx.xxx and below it I identified a thickness that does not fall completely within the range of the mil-spec

More specifically I said process per mil-spec -xxx.xx, and apply a coating thickness of .0004-.0008. However, the mil spec recommends a minimum of .0005.

In our business we use the anodize primarily for aluminum protection and color, the thickness range was recommended by the coating business who applies this anodize per the mil spec all day every day. When I say protection I simply mean no oxidation, it is a hand held device that does not mate with anything.

I originally thought it was no problem but I am starting to second guess myself. The mil-spec provides tons of information, and we deviate from one small portion of it to fit our needs, but we aren't military.


I feel like our drawings are the final say, so if we state process per the mil-spec but then below it we have a small deviation than its legit. Obviously we want 99% of the process to be followed so it wouldn't make sense in my opinion to do it any other way.

What is everyone's take on it?

 

[hydtools]

If you are not performing under a military or government contract, I would say yes. Otherwise, you would need to request an exception to the contract.

Ted

 

[Spoolx]

Thanks kind of what I think. Our drawing dictates the end result. I just wanted a second or third or fourth opinion because its been bugging me.

 

[KENAT]

If you want to feel better then change the wording of the note:

FINISH SHALL BE PER MIL-SPEC -XXX.XX, EXCEPT WITH COATING THICKNESS OF .0004-.0008.

Then get on with your day which is clearly going pretty well otherwise if you're concerned about this.;-)

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[3DDave]

It seems like a reasonable exception. As long as the end result is not being sold as conforming to the MIL-SPEC, but you are using it as a basis, it's all good.

 

[tbuelna]

It is perfectly acceptable to specify processing in accordance with a MIL spec with a noted exception. Assuming of course that the exception is within the process capabilities. Just remember that when you specify any variation from a standard process the vendor is qualified to perform, you may also need to define what QA procedures are required by the vendor to verify their work conforms to your specific requirements.

If the anodize coating is for corrosion protection and cosmetic purposes, and there is no need to maintain tight dimensional control of the coated part surfaces, why are you specifying a .0004-.0008" min/max limit for the coating thickness rather than the .0005" min coating thickness in the standard?

 

[IRstuff]

Agreed, you are WAY overthinking this. Mil specs are primarily about consistency, rather that absolute mandates, and even then, they're only mandates when contractually stipulated.

TTFN
I can do absolutely anything. I'm an expert!
faq731-376 forum1529

 

[Spoolx]

Thanks for the reply guys!

 

[dgallup]

We have a standard for interpreting our drawings called out on every drawing. One of the things in the standard is the order of precedence. In case of conflict, the drawing always has precedence.

----------------------------------------

The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.