CNC Programming Techniques: An Insider’s Guide to Effective Methods and Applications

When it comes to programming a knurling operation on CNC lathes, there is nothing simpler in terms of the actual tool motions:
Rapid to a start position
Feed in for the length of knurl
Retract from part diameter
Return to the start point or a tool change position
If it is not any special programming technique, what makes knurling different from other simple tool motions? This chapter will look at several issues important for successful knurling on CNC lathes.
Knurling is a special usually uncommon machining operation that can be produced on manual and CNC lathes. Its primary purpose is to develop depressions or indentations in the material surface by a rolling action of the knurling tool while it is moving along the horizontal machine axis. Depending on the knurling tool, these indentations can have either straight, angular or a diamond pattern. The diamond pattern is also called the diagonal pattern or the cross pattern . Angular pattern can be left hand or right hand. Knurling is not a metal cutting action but a metal forming action caused by force. A large variety of tool holders is available for different knurling requirements.
Several manufacturers have developed knurling tools especially for CNC lathe machining, including modular tools with interchangeable heads. These are the tools recommended for CNC knurling. Some designs are suitable for knurling to a square shoulder with minimum clearance. The most important of the tools is the knurling wheel itself.

The three common pattern types...