Application of flash specification 1

[MacPlastic]

Hi guys, hope this is the right area to be asking this question...

I'm seeking guidance on the application of specifications for defects such as flash. I will use an example to explain this.

If you are measuring the overall length of a component/feature and there is flash on one end of the feature some of our quality folk seem to think the flash needs to be within the tolerance for that feature. As far as i am concerned there is a specific tolerance for that feature which always applies and there is (or should be) a separate tolerance for flash i.e. you measure the feature length excluding the flash then apply the flash spec to the flash itself.

My problem is convincing Quality I am right. Do you know if there is any official referece or standard which provides guidance on such matters?

Any & all help appreciated!

 

[pmarc]

This is what ASME Y14.8-2009 "Casting, Forging and Molded Parts" says:
"The limits of permissible flash extension shall be specified on the drawing. Flash extension may exceed perfect form boundary at MMC unless otherwise specified."

In my opinion this proves you are right and not the quality guy.

 

[MacPlastic]

Thanks for the reply pmarc.

I presume "Flash extension may exceed perfect form boundary at MMC..." means that the feature length in my example can be at the upper tolerance limit and flash can still exceed this.

This is very helpful, thanks!

 

[dgallup]

I agree, have problems with this with quality inspectors all the time. I tell them to measure the feature, not the flash. Measure the flash separately. I usually put a general allowance for flash and then additional notes if needed to either restrict or allow additional flash in specific locations.

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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

 

[KENAT]

MacPlastic, assuming you're in the US working to ASME stds then like pmarc references take a look at Y14.8.

Do ou have specifications for the limit of permissible flash extension on your drawings?

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[MacPlastic]

Thanks for the feedback guys...

dgallup - that sounds like a good approach to me!

KENAT - i'm in Europe but many of our customers are US based and would use ASME standards. I must get my hands on Y14.8.
We generally have (or will ask for) a spec for flash on the drawings, even so this argument comes up with Quality