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<p>First things to check is whether or not you have a nice sharp bit. That can cause troubles.</p>
<p>The next is to make sure you have the right feed and rpm for what you are up to. That is all related to your milling bit diameter and the number of flutes.</p>
<p>For instance, a 1/8th endmill with 2 flutes should be around 7640rpm and you can run at 76.4 inches per minute. A 4 flute can run twice the speed (152.8 inches per minute) because the flute can carry twice the number of chips out of the cutting area. As you move up in endmill size, the rpm and ipm drop in half, so a 1/4" mill can run 3820rpm and 38.2ipm. That is all assuming that you can enough torque and speed in the steppers and the milling head.</p>
<p>The next thing to worry about is removing the chips. If you leave alot of chips in the channel that you are cutting, the milling bit ends up having to 'recut' those and that can cause everything to gum up. Vacuum or blow the chips out of the way as you are running is the best bet.</p>
<p>The final thing you need to worry about is your cutting tool flexing. Once you start to flex it, not only does your cutting path go wrong but you'll likely end up breaking it. Bigger diameter tools are stiffer so they can take deeper cuts. If you are using a skinny tool and have a couple inches hanging out under your milling head, it will flex and cause troubles.</p>
<p>All that being said, I run at 15 IPM for aluminum with a 1/4" mill and 25mil cuts. Works ok. When I go to smaller milling bits, I actually reduce the speed down to around 5ipm just to make sure that poor thing isn't flexing.</p>
<p>Aaron</p>
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<p>On Sun, 29 May 2011 11:14:21 -0400, Darcy Whyte wrote:</p>
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<p> I tried to cut aluminum for the first time last night. Pictures of the results here <a href="http://mambohead.com/2011/05/first-try-at-aluminum-with-cnc-mill/">http://mambohead.com/2011/05/first-try-at-aluminum-with-cnc-mill/</a></p>
<div>I think I had the feed rates wrong. Anybody have any idea why the endmill gummed up?</div>
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