Curve fitting with arc splines for NC toolpath generation

Arc splines are important in automatically controlled complex curve cutting process. However, the problem of how to determine the parameter of arcs according to desired curve fitting accuracy has not been completely solved. This paper presents a new algorithm for finding arbitrarily close bi-arc splines. It is based on research on the characteristics of spiral curves. The algorithm has several features: (1) The curve fitting error can be calculated by a simple formula; (2) Number of segments can be predicted before curve fitting; (3) Compared with other methods, it is relatively simple and has a high computation efficiency.