Gene Heskett wrote: > Assuming I keep the area wet with cutting oil at a high enough flow that I > don't wind up with a muddy slurry, but do have enough chips to act as a wick > and keep the mill wet from the cutting oil they absorb (or the oil level in > the tuna can is high enough), and the 1/8" 2 flute carbide upcut spiral mill > is turning 2500 rpms, how fast can I feed it while doing a 0.020" deep cut > per pass without breaking it? Slower and deeper, or shallower and faster for > best tool life? > I've been using 4-flute more than 2-flute. You get more cutting edges, and the core is supposed to be a little stronger, at the expense of less room for chip flow. In aluminum, the problem is the back rake, ie. you can cut so fast the back of the flute is rubbing on the work. I have much less experience in steel, and have had problems with breaking the bits, and also had to go insanely slow. I once forget to zero the Z axis and had a 1/8" carbide end mill plunge fully through a 1/8" aluminum panel and then start plowing full-width at 40 IPM! It only broke when I hit Estop. I don't know how long the cutter could have withstood that abuse, but it made over an inch of slot before I stopped it. Mostly, you want to take as large a cut as the tool, workpiece, fixture, etc. can handle. Excessive vibration is to be avoided, as it causes wild fluctuations in chip load. You usually can plunge 1/2 the end mill diameter per pass when plowing full width, and maybe an engaged length equal to the mill's diameter and half the diameter depth on the side. 2500 RPM is pretty slow for 1/8" carbide. In medium steel, you want about 250 SFPM, or 7500 RPM.
So, the basic rule is take as heavy a cut as you can without causing tool or workpiece deflection. For medium steels, .003" chip load per inch of cutter diameter is recommended. So, for a 1/8" cutter, that works out to .000375" per tooth. For a 2-flute end mill at 2500 RPM, that is a disappointing 1.9 IPM. Jon ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
