Coolant - No Coolant

To All:
    I am doing some 2" X 2" X 2" 17-4 PH aerospace parts that are quite involved with about 5 setups (bores, radii, angles, profiling, form
tools, etc.). The first setup uses some 13 tools. Anyway I'm using a Mitsubishi .750 dia. three inserted end mill that roughs out most of the material.     With flood coolant the inserts lasted about 4 parts. Cutting dry the inserts last about 10-12 parts, or 2 1/2 to 3 times longer.     So the moral of THIS story is; if you're having insert life problems cutting 17-4 or 15-5, - try running dry to see if there might be an improvement. Check your inserts frequently the first time you try it so you don't fry your cutter body. We used to use Iscar cutters, but since Mitsubishi replaces their cutter bodies if they are destroyed, we've started using them almost exclusively, at least in the smaller sizes.     
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BottleBob
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wrote:

Had the same problem a few years back cutting some 3/4" 4140 bar. Was using a Ceratip ceramic insert. Had to turn it down to .676" dia. x 2.25" long. Not much of a DOC, but the chips were long and stringy, turned into a rats nest that would rap around the part, and the inserts were failing prematurely, maybe 30 pieces per side. Needed to make 3000 peices, and this wasn't gonna cut it, pardon the pun.
Called the tooling guy , "This tool sucks!" "Calm down Matt." After explaining what I was trying to do, he said to kick the RPM & feed up, and Turn The Coolant OFF!
Excuse Me!!?? Turn the coolant OFF???
"I don't think so, Dude!"
"Matt...I'm tellin' ya. Turn the coolant off and cut it dry" "If you trash the holder, I'll give you a new one and a box of inserts."
OoohKaaaay.
I wouldn't have believed it, if I hadn't actually done it myself. Damn.... the chips crumbled, and were red hot as they *flew* off that tool....... and the parts were Cold! The finish was gorgeous, and the inserts lasted for somewhere between 150-200 pieces per side.
Awesome...simply awesome.
Matt
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On Tue, 11 Mar 2008 12:20:17 -0700, BottleBob
<snip>

<snip> =============If this was anyone but a regular poster I would think this was a troll and skip it. So "Everybody Knows," and "They Say" are wrong again
Any idea what's causing this? Are the inserts wearing, chipping, cratering, or what? Any special coating? How do you keep the chips removed w/o coolant? What kind/brand/concentration of coolant were you using? Inquiring minds want to know....
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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F. George McDuffee wrote:

George:
    The inserts tend to "notch" at the depth of cut. I believe thermal shock to cutters and inserts by flood coolant is semi-common knowledge.
http://tinyurl.com/28e2k9
    Read the paragraph titled: "Cutting fluids for machining".

    The parts are raised above the vise, with no pockets, so the chips tend to fall away and not get recut an excessive amount.

    We use Hangsterfers S500 soluble. We run the coolant on the rich side 10%-12% since we cut a number of different materials, some easy some difficult. Plus we do a lot of form tapping.
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LOL
I cut mostly aluminum....
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Get a set of these - <http://www.wihatools.com/pro_magicRing.htm
They also make them in Torx.
--

Dan

CNC Videos - <http://tinyurl.com/yzdt6d
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Dip the torks driver into a glob of grease first.
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