General cleanliness call out? What is the best way to do this without going overboard. 2

[dennisbernal91z]

I am product engineer working for a company that makes medical blood analysis equipment. We do not make anything that touches a patient; it is all just lab equipment. My company sells mainly to second and third world countries. The market we cater to is small labs that can't afford big name analysis machines. This is all important because I need my drawings to reflect that in the sense that I can't spec something up because if I do, our price per piece will shoot up and then we need to pass that onto our customers and they can't afford it.

So with all that being said, does anyone have any suggestions about how to call out a clean part? What I am looking for is if a part gets machined, that it gets rinsed off, maybe tossed in an ultrasonic cleaner to get all large particulate off, and then blown dry with filtered dry air. That’s all. Parts don't need to be incredibly clean, just decent. I know this is ambiguous so it makes it impossible to say there is a pass fail, but I need to put something on there so clear things up.

Finally, being a small company, we don't have very much equipment. Just microscopes and magnifying loupes, and those are not even over in out inspection area. We use those things for production, but could bring them over if need be.

Either way, just want to hear some opinions.

Thanks.

 

[DRWeig]

Clean until the engineer says it's clean.

Best to you,

Goober Dave

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[MintJulep]

Future cost is a risk, not a cost,

With vague requirements the supplier never knows when, how many or why a part may be rejected and returned for rework at his expense.

A clued-in supplier recognizes that, and includes a factor in his price, hence it will be a direct cost to the vague specifier.

However it seems likely that the OP's company is not dealing with clued-in suppliers.

 

[KENAT]

I had a similar question a few years back thread1103-165640.

Our attempt at a general note which is of varying success:

FINISHED ARTICLE SHALL BE FREE OF OILS, LUBRICANTS AND OTHER CONTAMINANTS PRIOR TO BEING PLACED IN SEALED BAG.

For really clean parts we have serious cleanliness requirements based on our industry standard.

FINISHED ARTICLE SHALL MEET CLEANLINESS REQUIREMENTS OF IEST-STD-CC1246D LEVEL 100 (VERIFY CORRECT LEVEL). IF NOT TO BE USED IMMEDIATELY THEN TO BE ENCLOSED IN PACKAGING TO IEST-STD-CC1246D LEVEL 100 (VERIFY CORRECT LEVEL) LABELED: “CLEANED, DO NOT OPEN OUTSIDE OF CLEAN ROOM”. COMPLIANCE WITH THIS REQUIREMENT BASED ON USE OF A QUALIFIED MANUFACTURING PROCESS IS ACCEPTABLE.

ITEM SHALL BE ASSEMBLED IN A CLASS 6 (VERIFY CORRECT CLASS) CLEAN AREA MAINTAINED AS PER ISO 14644-1. (CLEAN AREA TO FED-STD-209, CLASS 1,000 (VERIFY CORRECT CLASS) IS ACCEPTABLE ALTERNATIVE.)

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[dennisbernal91z]

IRstuff: You hit the nail on the head in terms of understanding my question! Thanks you. You read me like a book, I did not bother reading the NASA spec. I figured it would be far to much for my needs, but I was wrong. Their VC spec is what I am shooting for. Just a clean part free of major particulate. I agree that specs not being 100% clear is risk, but if you know anything about working for a company like mine, small and in a very competitive field, risk is what we eat for lunch! We simply can't afford to spec our way out of it. I have to manage large and small risk every day.

Anyways, thanks for the insight to all. I will pass the NASA style spec past my boss and see if he likes it. (He is not an engineer, but heads my department anyways.)

 

[IRstuff]

Even in the case of numerical specifications, like minimum resolvable temperature difference (MRTD) of, say, 0.5°C, the test method used a 4-bar target whose temperature was computer controlled, but the resolvability criteria was performed by a person, who looked and looked while the temperature was changed and the tested value was when the person declared that he could no longer see all 4 of the targets. To make it more scientific, we went in both directions, in case there was hysteresis in the instrument (person). Naturally, we had a gold standard person who swore they could still see all 4 bars long after most people could even tell if there were 2 bars visible.

If everyone plays nicely, such specs are usually not that much of a risk. And in a competitive environment, most suppliers bet on the come to ensure getting the job, rather than pricing for failure.

TTFN
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