There are quite a few things that you can do in order to modify the feed rate for circular motion commands. When you are using a circular motion, the length of the cutter’s centerline movement will be different than the work surfaces movement. The ratio between the work surface path’s radius size and the centerline path’s radius size determines how much you should increase or decrease the circular motion feed rate. The same exact ratio exists for internal arcs as well, so be ready to do some math.
- In circular motion, the work surface’s circular movement differs from that of the cutting tool’s centerline circular movement length.
- Single point cutting tools also exhibit this issue during lathe tasks but their small nose radius makes such effects less noticeable.
- Certain CNC manufacturers, such as Heidenhain and FANUC, have designs to help with this issue.
“When milling a two-axis contour at 10.0 ipm, it is the cutting tool’s centerline that moves along at 10.0 ipm.”