Variable feed rates and variable machine forces for a constant material removal rate and constant cutting force along Pythagorean-hodograph curves

This paper proposes a new machining strategy to realize better dimensional accuracy as well as surface finish. The strategy attempts to keep cutting force and the material removal rate approximately constant and force the tool to move along a so-called Pythagorean-hodograph curve, which is a group of analytic curves with special properties, in a milling operation. In conventional milling operations, a constant feed rate is frequently used. This would invariably lead to higher material removal rates in concave regions and lower material removal rates in convex regions, and affects dimensional accuracy. This work aims to establish the theoretical basis to show how the above-mentioned phenomenon can be predicted. Additionally, chattering is a well-known problem in machining. In this work, it is postulated that keeping certain machining conditions approximately constant would help in reducing chattering during machining. A numerical example is given to illustrate the proposed machining strategy.