"Break sharp edges" note
"Break sharp edges" note
(OP)
Hello,
I have a pretty simple question - I know that its common to call out "break sharp edges" on machined parts. I'm curious, what tool do they generally use to do this?
Or for instance, on a machined aluminum I-beam, what would be the most common way to remove the sharp edges from the flanges? Would you generally just machine a chamfer along the length of the flange? Or would you just run some tool along the length of the flange to break the sharp edge?
Thanks much...
I have a pretty simple question - I know that its common to call out "break sharp edges" on machined parts. I'm curious, what tool do they generally use to do this?
Or for instance, on a machined aluminum I-beam, what would be the most common way to remove the sharp edges from the flanges? Would you generally just machine a chamfer along the length of the flange? Or would you just run some tool along the length of the flange to break the sharp edge?
Thanks much...





RE: "Break sharp edges" note
I must admit I don't know what automated process might be used on something like you say.
KENAT,
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RE: "Break sharp edges" note
Cheers
Greg Locock
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RE: "Break sharp edges" note
Another device common in the sheet metal industry is a scraper with two circular blades that can be set to the thickness of metal you are working, this device removes about .005" from each corner of the edge of the sheet.
B.E.
RE: "Break sharp edges" note
Power deburring tools include the "burr beaver" and "burr king".
Not so Greg.
"Standard for Determination of Sharpness of Edges of Electrical Equipment," U.L. 1439.
There is a "standard finger" for such things. http://www.sharpedgetester.com/
RE: "Break sharp edges" note
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: "Break sharp edges" note
You have the types of tool, I mentioned and a few more.
B.E.
RE: "Break sharp edges" note
RE: "Break sharp edges" note
If you want sharp edges removed in a certain manner then specify it. And the more specific you are the better. Don't leave things open to interpretation by using ambiguous drawing notes like "Break sharp edges". Specify the shape and form of the edge breaks, the permissible tolerances, and the process to be used to produce and validate them. A proper edge break may seem like a rather insignificant feature, but a sharp corner bearing into the fillet radius of a mating part can (and often have) cause big problems.
Adding callouts and notes specifying proper edge break processes on your drawings doesn't take much effort.
As for edge breaks on the flanges of a machined I-beam, the easiest, most consistent, and reliable method would be to program the machine to run a chamfering cutter along the flange edge as a finish operation. That way it always gets done exactly the same on every part, and is usually much quicker than doing it by hand.
Good luck.
Terry
RE: "Break sharp edges" note
-sandblasting
-deburring tool
i usually call out 0.020/0.030 for structural parts and 0.005/0.010 for small parts that require precision.
It is not uncommon for the fabricators to forget to break sharp edges.
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RE: "Break sharp edges" note
RE: "Break sharp edges" note
RE: "Break sharp edges" note
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RE: "Break sharp edges" note
This has been debated before if not on this forum then others.
Putting exlicit limits can create arguably excessive inspection requirements for many applications.
Many use the "Remove sharp edges .005 max radius or chamfer" or similar. However putting 'break sharp edges' doesn't give a pass fail criteria unless you use something like the 'finger simulator' at Mints link.
I've yet to find a true, one size fits all, solution.
KENAT,
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RE: "Break sharp edges" note
"Good to know you got shoes to wear when you find the floor." - Robert Hunter
RE: "Break sharp edges" note
You can scrape the sharp corner, sand it, use a highspeed rotary burr bit, a file, sand paper, emerypaper/cloth, a grinder, scotchbrite pads, rolled emery cones, etc etc.
RE: "Break sharp edges" note
Re. OP:
If you, the designer, does not specify how to break the edges, the operator will use what ever tool he thinks is appropriate. And you will, to some extent, loose control over your part. In some cases it will be acceptable but not always.
As long as the part is made iaw the drawing the designer is responsible. That's why you shouldn't allow others to influence the final result by being unclear when writing drawing notes.
RE: "Break sharp edges" note
You should spec the 'what'.
KENAT,
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RE: "Break sharp edges" note
I agree with KENAT. On my drawings, there is a standard note that says to break edges, and there is another note specifying a maximum corner radius of 0.5mm. All of this is "UNLESS OTHERWISE SPECIFIED" of course.
When I visit machine shops around Toronto, I see things that look like dental tools. I assume they use these to take off the edges.
RE: "Break sharp edges" note
I was being general in my comment.
I think the designer should know what he is doing when he leaves something for the next guy to decide.
Assuming is not a good word here.
I do not think we disagree, really.
D
RE: "Break sharp edges" note
Guess how I know?
B.E.
RE: "Break sharp edges" note
Human sharp edge detector.
Looks great when you're doing a fit check with the customer etc around and you slice your finger open on the part.
KENAT,
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What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: "Break sharp edges" note
Youuuu got it.
B.E.
RE: "Break sharp edges" note