Arguing Rigid vs Non-Rigid for inspection

[Vindicit]

So I have inherited a few problems with a company I work for. All of the parts that we manufacture are thin sheet metal that can bend with even a 1 lb weight on them, they bend and deform in assembly that is their intent. The problem is that these parts have been manufactured since the 1970s and all of them are dimensioned as if they are rigid parts with no restraint note (even brand new parts come without a restraint note). The only reliable way to inspect these parts is in a restrained condition.

How can I argue to customers/engineers/auditors that the parts need to be restrained to be inspected and not be "in the wrong"? In Y14.5 it does not specify what is a rigid part and what is not. The only way is by the initial drawing to state a restraint note or not. But what if a part is truely non-rigid and no note is present?

 

[3DDave]

Only argue if someone is throwing away usable parts. Other than that, no one will care and they will concentrate on the person making everyone else miserable.

On a theoretical/standards compliant basis, there should be a restraint note, probably with locations and values in line with what a factory worker can do to push the part into position. I've seen parts that this was ignored and the loads required to install parts correctly were conveniently measured in the thousands of pounds. Some were installed with come-alongs.

 

[Vindicit]

Sometimes we get auditors in here saying they can't pass our parts since we restrain them when we inspect them when the drawing doesnt state that we can. So basically that would scrap every part made. The problem is that getting a drawing change costs companies months and thousands of dollars and are unwilling to do so. Especially for old parts that havent any any revision since the 1980s. Some auditors understand that our parts are non-rigid and others give us a very hard time.

 

[Belanger]

Obviously, anything can be "non-rigid" if you impose enough force on it. So the best definition of non-rigid is something that, in its normal function, is meant to flex. That still leaves some questions, I suppose, but your initial post clearly states that the parts you're dealing with are meant to flex.

So...if your drawing imposes the Y14.5 standard then yes there should technically be a restraint note. Does the drawing mentions Y14.5? Or maybe any internal company standard where you could appeal to restraint? (Using a company document is a common way of "weaseling" out of mentioning restraint on the drawing.)

 

[3DDave]

There's no magic wand. If you are a service company then either stop accepting contracts for these parts or get them to change who is doing the auditing or change the drawings. I do feel your pain but, as I mentioned, there's no magic wand.

 

[Vindicit]

The drawings invoke Y14.5-1994, the older ones possibly 1982 still. Usually the companies do state their own internal drawing interpretation spec. Ill have a look at some of those.

 

[drawoh]

Vindicit,

The standard Y14.5M-1994 explicitly discusses Free State Variation (Section[ ]6.8). Ideally, there should be a note on the drawings stating how the parts should be constrained. If the parts are to be inspected in free state, you should be able to make inspection fixtures.

--
JHG

 

[Tunalover]

You could design a fixture that mocks how the part is installed. But if the part is still non-rigid in the as-installed state, then you need to MAKE it rigid in a fixture that does more than just mock the as-installed condition. You've gotta set some rules to insure repeatability and eliminate all concerns.

ElectroMechanical Product Development
(aka Electronic Packaging)
UMD 1984
UCF 1993

 

[truckandbus]

Add a note to your quality manual defining the requirement as applicable unless specifically waived on the face of the drawing and/or add the requirement to the component POs/RFQs as part of the scope of supply