CNC: Nose radius selection – something you have to poke your nose into
Selection of the nose radius depends on the depth of cut and the feed rate that you propose to use. The nose radius decides:
1. The surface finish
2. Insert strength
3. Chip breaking
Want to reduce part bending, vibrations and poor surface finish ?
Axial cutting forces are preferable to radial, because radial forces cause part bending, vibrations and poor surface finish. The higher the depth of cut, the more the proportion of axial forces to radial. So increase the depth of cut. Ensure that in general the depth of cut is more than 2/3 of the nose radius.
Want better chip breaking ?
Chip breaking depends on the nose radius and feed rate. At the same feed rate, a smaller nose radius gives better chip breaking. So to improve chip breaking, either increase the feed rate or reduce the nose radius.
General rule for nose radius selection
Use small nose radius for : small depth of cut, slender parts when you want to reduce vibrations
Use large nose radius for: High feed rates, large depth of cut, sturdy parts.
Text and pics. source: CADEM NCyclopedia multimedia CNC training software.
