Overview

If drawings of the same multiaxis part were given to five different CNC programmers, chances are good that they would come up with five different methods to machine the part. This variability is a product of experience, available multiaxis equipment, available CAD/CAM systems, tooling, fixturing, material, and quantities.

What does every CNC programmer do when asked to write a program for a new part? He or she will create a mental image of the part, and based on the above factors, go through a variety of different scenarios to determine how to machine it. These decisions will include how to hold the part, and which side to start on. The programmer will then mentally go through the whole process of removing all the excess material from the starting stock in order to free the desired part from within it. Most programmers will brainstorm repeatedly and come up with multiple solutions, eliminating the weakest ones, adding new ideas, and then making the final decision. This whole process happens long before the creation of the actual toolpath. This pre-work meditation is the single most important part of the whole manufacturing process.

The process described above is the same, whether 3-axis or multiaxis work is being considered. The big difference is usually with the fixturing. Work holding is among the first decisions to be made when programming a 3-axis machine. Many multiaxis programmers will place the part data on a virtual machine. This process lets them levitate the part in the air...