Inspection Dimensions

[MadMango]

I'm looking for a standard that identifies dimensions being surrounded by an oval/oblong to mean "inspection dimension".

We use SolidWorks, and they have this feature to enable an oval on dimensions to mark them as inspection. Our QC department would like to start using this feature so they can reduce the number of inspection criteria for manufactured components.

[green]"Art without engineering is dreaming; Engineering without art is calculating."[/green]
Steven K. Roberts, Technomad
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[ctopher]

Wouldn't that be the same as "critical" dimensions?
thread1103-165581

Chris
Systems Analyst, I.S.
SolidWorks 06 4.1/PDMWorks 06
AutoCAD 06
ctopher's home (updated 06-21-06)

 

[smcadman]

http://www.eng-tips.com/viewthread.cfm?qid=53176&page=11

Flores

 

[MadMango]

I'm suppose to remember back 3 years?

Thanks for that link. I guess there still isn't a definitive standard then.

[green]"Art without engineering is dreaming; Engineering without art is calculating."[/green]
Steven K. Roberts, Technomad
Have you read faq731-376 to make the best use of Eng-Tips Forums?

 

[smcadman]

I had found that link about the inspection dimension awhile back and wondered why you wouldn't use a basic dimension instead.



Flores

 

[KENAT]

Um,

smcadman, how well do you know GDT? Basic dimension doesn't directly correlate to how critical it is or how frequently it should be inspected etc. Basic gives a theoretical point(some times line etc) that another form of tolerance is then applied to.

MadMango, I've seen the symbol on CAD systems. There's no reason you couldn't raise a company spec or (if it's brief) even add a note to the drawing saying that dimension in the descriped bubble are to be 100% inspected etc.

Some of the refs Swertel gave on the critical characteristic thread may point you in the right direction too.

Essentially as long as you define it I guess you can use pretty much whatever symbol you want. Trouble is if it's a company spec and the drawing ever gets separated from the spec it can cause problems.

On the other hand QA can come up with a quality/inspection plan and decide which dimensions to measure how & how often without the drawing even changing. They can reference the dimension something like "1.250 dimension location 3B" assuming you have a grid on your formats. This is what I've most often seen.