Break Sharp Edges note 4

[boottmills]

I'm trying to see if anyone can interpret what a note I have on a vendor drawing actually means.

"BREAK ALL SHARP (90% OR SMALLER) EDGES OF ALL SHEET METAL."

I've never seen the note stated that way before. Any idea what it is requesting?

~Boottmills

 

[cowski]

I think they really mean 90° instead of 90%.

 

[CheckerHater]

This is how the side of sheet metal part looks like enlarged.

As you can see, one side of it contains burr - feature that appears as sharp, "less than 90 deg." in absence of better word, edge.

Removing said edge seems the only interpretation I can come up with.

The percent sign could be result of using non-compatible font or something.

But I am open to suggestions.

"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future

 

[KENAT]

I'd lean towards what the others say - can you not ask your vendor?

Posting guidelines faq731-376

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

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

 

[drawoh]

boottmills,

I cannot make sense of your note. There ought to be a standard note on your fabrication drawings to break all burrs and sharp edges. On my drawings, I call up a maximum corner radius of 0.5mm. If you want anything more complicated than that, you need to show it in a view.

--
JHG

 

[boottmills]

Drawoh,
I can't make sense of it either! It's not my note!

KENAT,
I have an e-mail out to the vendor for a couple of days now...I think they are avoiding me.

I was thinking that it may just be someone not knowing how to use a ° symbol while typing...but want to be sure. Glad to see that I'm not the only one to have a bit of confusion with this note.




~Boottmills

 

[Tunalover]

How about simply "BREAK EDGES TO RX.Y." where your format block tolerance applies. X and Y are of your choosing.


Tunalover

 

[boottmills]

Just heard back from the vendor - here is the response from their engineer:

"I'm not exactly sure what this means as well, I would just call this out as 'break all sharp edges'."

ARE YOU KIDDING ME! This is his drawing...his signature is on it as the engineer!

Thanks for your help guys...





~Boottmills

 

[tbuelna]

Just a thought. Since the note applies to removing sharp edges of sheet metal parts that might be quite thin, it seems like there was possibly some attempt to control the max size of the edge breaks based on the sheet metal thickness. For example, if the sheet metal is only .020" thick and the edge break note specifies "break sharp edges .010" min", you have a problem. So in this situation it might be better to use an edge break note that defined the limits of the edge breaks as a percentage of the material thickness.

 

[3DDave]

I'd just settle for - If the edges draw blood, they are too sharp. I'm looking at you auto makers and your sharp sheared parts under the hood and dash.

 

[tbuelna]

Heh. So the QA process would involve the inspector running his finger along the edges of the part, and if there is any bleeding from his fingers the part gets rejected? Does this job pay by the hour, or by the volume of blood lost?

I agree with your comment about razor sharp edges on body panels. I have been to the hospital twice to get my hand stitched up from gashes caused by sharp edges on auto body sheet metal.

 

[3DDave]

No - QC guy makes the sales guy from the supplier do it. It's fun to watch a Herb Tarlek type, with blood running, claim it's not sharp, not sharp at all, while a small puddle forms next to him.

Honest - I had one of these lying weasels contest that the ball bearings in their assembly weren't sealed. I point out the regularly shaped blobs of grease that are going at exactly half the shaft rate as I turn the shaft and he tries to tell me that its grease build up on the shield. They also claimed an item was passivated - an item that looked like a wooly caterpillar after 2 hours in the salt fog chamber (passing was 24 hours and no specks.) The final straw was when a gear fell off the end of a sensor. They first claimed mishandling then, with the second one, stated we had not specified an axial retention requirement. Sigh.

Few sales guys are like this, but any that claim a razor edge has been deburred? Start with him and move towards upper management.

 

[tbuelna]

I've seen the polar opposite situation, where a vendor submitted a DR because the required .060" max corner break on one part measured .005" over. I accepted the part as is, and thanked the inspector for doing such a thorough job.

 

[lifttrucks]

No blood required: Sharp Edge Tester