Question for inspectors

[cjccmc]

For those who have to inspect and approve parts with illegal or impractical GD&T, how do you deal with it? I regularly see designs with illegal GD&T and yet we have parts made, delivered, accepted by our QC and put into use. I asked our inhouse Mfg advisor about this and he is convinced that there is no one answer, thinks that the handling depends on what company is making what part and even then you get a different answer depending on what person you contact there.

Is there some kind of work around in these cases? Just curious about how that is handled.

 

[Belanger]

When I'm asked to look at prints, I try to point those out up front, as diplomatically as possible. However, at many facilities it's true that often things just gets swept under the rug, with the saying, "Hey, we've been making this same part for 4 years and there's never been a issue."

The problem is that when an issue does rear itself down the road, the bogus GD&T on the print could be a point of liability. Remember that a drawing is a legal contract to make a part to the given specifications, and if the drawing is ambiguous or wrong, that will point dthe finger of liability to the company whose name is in the title block. There are a few stories of prints being hauled into a courtroom and having a GD&T expert give testimony about the validity of certain callouts.

So I would say that any goofy or illegal GD&T should be brought up, but I know it depends on the timeline of the project. Interesting to hear what others will say about this.

John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems

 

[powerhound]

I've seen this time and time again. What makes it worse is when the QC department doesn't have a clue. I've been in discussion about attaching datum identifiers to centerlines and have shown where the practice is explicitly prohibited by the standard and I still get "Well it depends on how you interpret it." How can that possibly be misinterpreted?

As JP said, I also hear the "making the same part to this drawing for years" excuse.

John Acosta, GDTP S-0731
Engineering Technician
Inventor 2013
Mastercam X6
Smartcam 11.1
SSG, U.S. Army
Taji, Iraq OIF II

 

[fsincox]

It seems the time of fix it just because it is wrong is long over!
Frank