Edge breaks - how to measure- what is the true definition? (aerospace industry)

[desii]

Hello everyone,

I currently work as a Quality Engineering in an Aerospace company. As of now, there has been a great debate between the Engineering team and the Quality team about edge breaks.

Current situation is drawing note calls "must break all sharp edges .005 R max"

Is there any standard available that explains exactly what an edge break is by definition (possible examples?) Per the note above I believe an edge break can be either a chamfer or a radius at the end. However, simply putting that note on the drawing cannot guarantee the supplier has to do a radius each time or a chamfer each time (they chose how they want to)

Is my understanding correct?

Next thing- what is the proper way to measure an edge break? We currently are using the a contour tracer which Engineering agrees with and Quality hates it. I see both sides but my biggest issue is how subjective the measurement is. We have access to a shadow graph, CMM, contour tracer, and a few other tools.

I appreciate any help.

 

[Sem_D220]

ISO have a standard on how to specify edge break or allowed burr. Here is some info:
Link

It seems to me that there is no distinction between rounded and chamfered edges. The specification from fig 22.3 allows both without indicating which geometry from fig. 22.2 is required.

 

[monkeydog]

Unless there the edge break is a critical feature (next higher assembly interface) or needed for the part to function correctly (sealing is an example) you are wasting time, money and energy specifying the edge break to be inspected. If the machine shop is leaving an edge that is cutting peoples hands, or butchering your part, then you need to find a new machine shop.

 

[drawoh]

desii,

I would treat your ".005 R max" as least material condition. Anything exceeding that should be accepted as long as it is not sharp. The key word here is MAX.

Why does this matter?

I have dealt with this problem on optics, where the clear aperture is critical. What geometry will cause your part to not work?

--
JHG

 

[jackk]

I agree with Monkeydog. Just have the inspector run their finger along the edge to see if it's good or not.

 

[3DDave]

I'd try a paper towel to look for sharp edges; fingers leave too much to clean up.