Rolling Into a Cut

May 15, 2010 // by Bob Warfield // Blog, Software, Techniques // No Comments

Here’s a great tip, courtesy of Sandvik, with a hat tip to Don “Milacron” at the PM Boards. This Sandvik video explains the gist of it:

I’m fascinated by these geometric effects. Chip thinning is another. Isn’t it interesting how Mother Nature tends to like circles better than straight lines? Chip thinning, rolling into a cut, and the trochoidal paths of high speed maching are all about the behavior of circles as we try to use them (in the form of rotating cutters) to cut the straight lines that we humans are more comfortable with. Circles are more gentle and natural in these applications. Here is another look at the geometry:

Not the chip shape to the right of the feed line (the red line is the path the cutter follows): thin chips on exit are better!

To execute an entry like this means starting the cutter out one radius to the right of the original starting location and then rolling it in along a path that is an arc with the same radius as the cutter. The folks on PM report that this works as well for endmills as it does for the face mills Sandvik shows in their video. In fact, they say it really helps improve cutter life on materials like Stainless Steel.