INSPECTION DIMENSION Standard

[roby]

Hello All

Does anybody know of a standard that describes the method to indicate which dimensions you want inpected on a drawing. SolidWorks and PRo/E use a rounded ended box around the dimension to indicate this, but I have been unable to find any standards for this pracice.

Cheers

Rob

 

[cobb]

Roby, I thought all dimensions on drawings needed inspection? Scott Cobb
CSM Manufacturing, Inc
csm-mfg.com

 

[looslib]

All dimensions should be inspected unless they are marked as being reference. I don't know of any industry standard symbol or designation that says 'this dimension must be inspected'.

When I worked in the automotive field, we put a synbol on certain dimensions that we marked as Key Product Characteristic and had a note that explained what the mark ment.
Ben Loosli
CAD/CAM System Analyst
Ingersoll-Rand

 

[swertel]

Likewise, looslib.

All dimensions are inspected, but we created a special symbol for special features that need to be validated for use. When we use the symbol, we create a general note explaining the symbol.

--Scott

 

[MadMango]

In the medical company I worked at, all dims were inspected, but some critical dims were marked with an extra symbol. This symbol was a stretched-out hexagon, that was divided into 2 sections horizontaly. The left side had a 3 digit code which described what type of inspection tools was used (digital caliper, steel rule, etc) and the right side indicated the sampling plan (how many to inspect per lot size).

I know some companies that use the CAD "inspection dims" bubble as a marker for critical dims. During first artical inspections, all dims get measured, but after that, only the critical dims are inspected for tracking. It's suppose to be a time saver, but I see problems with that, unless the parts are always made on dedicated machines. "The attempt and not the deed confounds us."

 

[Rentapen]

roby,
For MOST small to medium mfg'ers a number circled or star with a note is used. A majority out there ARE small to medium with a assembly consisting of only a few parts swaged, welded, pressed, or bolted together. They have no need of expansive cad systems or more then one assembly dash detail sheet. Ever try to check a shoulder diameter of a conveyor roller after assembly and sent out for first article packaging? You can not.
The important things to stay away from are the rectangular box (BASIC) dimension and things that may be taken other ways, if ISO have designated one yet please info me but as of yet I have not heard. A on-sheet tab with your customers or your spc/quality (which usual is taken from your customer or sales)dimension will thell quality what is needed for ppad-first article.
regards
just wandering
rentapen

 

[cobb]

What I should have said earlier is that all Dimensions need inspected but not all dimensions on all parts need 100% inspected. I am and have been in the contract job machine shop industry for 20 years and have seen more then my share of drawings come through with all kinds of symbols some from standerds that I reconized and others from who knows where. A great deal of manufacturing companies that make their own product line also have some of there own standereds but when these products are out sourced to various contract job shops we cannot take nothing for granite even if the customer says that this symbol means that this dimension is not critical to form-fit and function we still have to inspect it from time to time during a production run.

Thank for your time. Scott Cobb
CSM Manufacturing, Inc
csm-mfg.com