Actual machining question!

Got a shot at picking up a new customer. Parts are medical. Nothing critical, just that standards are high.
Simple shaft, 303, ground to an 8-16 microinch finish. What I'm asking
for suggestions on, is I have to mill two flats each end, and while I will of course optimize my process for a minimal burr, there is going to be sharp corners. Print naturally calls for all sharp edges to be deburred. I know this is a no sweat part for many shops, but I've not had to worry about doing cosmetic deburring before. In the markets I generally serve, vibratory deburring or scotchbrite wheel suffices. But quantities are well beyond what I want to do with scotchbrite and vibratory is not an option.
These will be turned, chamfered, parted off in an Omniturn, shallow flats in the mill, leaving 4 sharp edges per end. How would you all take off the sharp edge whilst best preserving the nice ground finish?
Thanks,
Jon
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Jon Anderson wrote:

You could machine deburr the parts when you mill the flats. Sounds like it anyway. Mill a small chamfer before you cut the flats and cut the flats in the direction that is self wiping. Maybe.
--

Dick



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Jon Anderson wrote:

Jon:
    Can you do the flats standing them up vertical? If so you might be able to program a small male radius entry and exit on the flats and a separate chamfer/radius on the end.     Or possibly have a custom end mill made with a radius/chamfer at the right height to do the top chamfer/radius.     Could you machine the flats on BEFORE grinding and then have them vibratory deburred and THEN ground? Leaving the bare minimum to be ground for surface finish purposes?
--
BottleBob
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wrote:

Not seeing the part this would be my first option as well.
1. Turn 2. Mill or Broach Flats 3. Deburr 4. Finish grind
And of course it you had one of Dan's machines it would be;
1. Run part complete starting with finished ground barstock.
Tom
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snipped-for-privacy@aol.com wrote:

When I get off my arse and win the friggin Lotto, I'll just do that!
Well, I got to wondering just what I might really run into with burrs, being 303 and all. So I milled a flat on some scrap stock, the burr is so minor, it easily comes off with my Nylox wheel, with minimal marking to the surfaces. Think I got myself worried over nothing.... I'm just wanting to make sure I make a good first impression. After years of trying to break out of the local (semi-rural) market, I recently landed a great new customer in the SF bay area and he referred these guys to me. Could be a nice start to replacing some of the local customers that have gone under or taken work overseas...
Thanks all for the suggestions.
Jon
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On Tue, 09 Dec 2008 19:17:45 -0800, Jon Anderson

LOL......well you were short on specifics so it's hard to make a viable recommendation lacking a sketch, job quantity, facilities list and material*.
Tom
*303SS Customer supplied? Barstock? Ground barstock? Cut Blanks Cut, ground blanks? Cut, partially machined, ground blanks? etc.
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On Tue, 09 Dec 2008 19:56:44 -0800, snipped-for-privacy@aol.com wrote:

Correction;
Went back to re-read your OP, I forgot you did specify material.
Tom
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Jon Anderson wrote:

Jon:
    Just a couple of more tid-bits.
    If you were going to hold the part horizontally (like in a 5C collet closer), you could use a keyed arbor and two slitting saw blades separated by a spacer ground to the correct dimension and do both sides at once.     With a manual horizontal mill you could do a whole row of parts at once with slitting saws.     Holding multiple parts vertically in a vise with bored soft jaws might be a little tricky, since a few of the parts might want to spin. You could try using one alum. jaw and one very hard durometer urethane jaw to squeeze the parts.
--
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BottleBob wrote:

Ahh, well as Tom pointed out, I was short on specifics.... I'm buying the material centerless ground to .3735 +.0000/-.0004 in 6' lengths. These, I'd saw to 2' lengths for the Omniturn since I don't have a bar feed. Face and chamfer one end, chamfer and part off to length. Also, the flats are at opposite ends, so yes, lining them up in the mill and doing a bunch at once is the plan. I have some obsolete tooling that I can modify very easily to do these. With two, I can load/unload while the other is in the mill.
Jon
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Jon,
What is the order quantity, or are you just running sample parts for now?
Tom
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snipped-for-privacy@aol.com wrote:

Tom,
Asked to quote 500 and 1000pcs. Company has been pulling work back in house, but not everything. When I was told that, I suspected they were just going to send out small lot work, but this has me thinking maybe it's the production they'll be sending out, so I'm especially interested in trying to make a good impression. While my company name is Prototype & Design, I learned very quickly there is nowhere near enough prototype work in this county to survive on even if I could get all of it. My nitch has been small lot work with fast turnaround but I will do any quantities that I can get. Obviously as the numbers go up, it's much harder to compete with more advanced shops. Largest single order I've run was 3000 pcs. 500-1000 is certainly up there for me.
Jon
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On Tue, 09 Dec 2008 11:20:09 -0800, Jon Anderson

----------- While it will increase cycle time, any possibility of adding live tooling [scotchbrite wheel] to the Omni setup?
Electrochemical [O/P]may also be an option. http://www.jobshop.com/techinfo/papers/electrochemicaldeburring.shtml http://www.thomasnet.com/products/electrochemical-deburring-21793500-1.html
http://www.deburring.co.uk/products.htm
Let the group know what works. Unka' George [George McDuffee] ------------------------------------------- He that will not apply new remedies, must expect new evils: for Time is the greatest innovator: and if Time, of course, alter things to the worse, and wisdom and counsel shall not alter them to the better, what shall be the end?
Francis Bacon (1561-1626), English philosopher, essayist, statesman. Essays, "Of Innovations" (1597-1625).
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I saw this at IMTS & it is what you are looking for...if you are doing a shitload of this type of work...
http://www.earthchain.com/deburring-equipment.htm
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On Tue, 9 Dec 2008 13:20:30 -0800 (PST), snipped-for-privacy@rise.zzn.com wrote:

----------- Looks like we may have a winner here.
Even if your volume is not enough to justify purchase, you may have someone with a machine near you that will do this as an o/p second op.
Any body have an idea what one of these costs?
Unka' George [George McDuffee] ------------------------------------------- He that will not apply new remedies, must expect new evils: for Time is the greatest innovator: and if Time, of course, alter things to the worse, and wisdom and counsel shall not alter them to the better, what shall be the end?
Francis Bacon (1561-1626), English philosopher, essayist, statesman. Essays, "Of Innovations" (1597-1625).
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snipped-for-privacy@rise.zzn.com wrote:

I've seen one of those before, they sure look to be the ticket for smaller parts. If I get into enough volume to justify one....
Jon
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