For CNC vertical machining center: a collet will hold the tool shank and provide timing orientation.
With the spindle locked, the broach can be brought in line with pre-prepared bore diameter and chamfer lead of the part to start
broaching the keyway at a speed of 10” – 30” in/min and an in-feed of .003” -.005” depth per pass,
using a flood coolant for lubrication during the cut.
Once the initial process is achieved, speeds can be increased to 50 - 80 IPM.
The in-feeding cycle is repeated until
the desired depth of the keyway is achieved. Chips can be removed from the bottom of the hole in a couple of ways:
In a blind hole bore, remove the chips by either:
Prior trepanning the bottom of the keyway area and allow chips to fall away.
Or pre-drill a hole from the outside to the inside of the part at the bottom of the keyway location.
With a through hole, you can broach right through, but do not disengage with the part, and simply deburr the keyway upon completion.