[HimyKabibble]

Originally Posted by BobWarfield Ray, SFM burns up cutters. Chip thinning is not about increasing the SFM at all. In fact, as you know, my mill has a very slow spindle on it, so it's hard for me to exceed (or even get to) recommended SFM for most operations. Compensation for chip thinning, lead angle, and ballnose cutters (all things G-Wizard does) are all geometric effects. Chip thinning is a function of the idea then when your spinning cutter is in a depth of cut that is less than half the cutter diameter, it actually doesn't cut as thick a chip at a given feedrate as for depth of cut greater than or equal to half diameter. In fact, what the calculation does, is simply to figure out how fast you have to feed just to get the same chip loading as would naturally occur were you cutting deeper. Hence, it works great with no impact on the tool life that is noticeable. As I mentioned on my steel cutting example, the machine ran very smooth and nothing got too hot at all. It was remarkably quiet. Those are all good signs, but don't take my word for it. Go out and search for "chip thinning" on Google. I'm surprised more people don't follow the practice. Heck, even my CAM program doesn't seem to bother, and it sure makes a difference. BTW, a combination of chip thinning and cutter engagement compensation are what pass for a lot of the HSM CAM toolpaths, like trochoidal cuts. When you can generate toolpaths that automatically take all that into account, your machine can really fly! Cheers, BW

Bob,

So you're applying chip thinning to normal square-tipped endmills? What I've read on chip-thinning applies to ball-nosed mills, feed mills, and other round-edged tools. I've never seen it applied to normal square endmills, as the chip thinning effect is a result of the curved cutting surface. If it helps get things done faster, without seriously compromising tools life, I'm all for it, I've just never seen it applied to normal endmills.

Regards,
Ray L.