Elliptical curve machining with variable feed rate for shape accuracy

Generally, tool path deviates from curved geometry as tool path interpolates linearly between two successive cutter location points. Deviation of the tool is directly proportionate with a curvature of the geometry. Any approach improving the shape accuracy is laborious and time consuming. The main objective of the present study is to reduce the problem of shape accuracy. This required generating a curved profile from a set of control points such that the tool moves smooth from one point to another point. Various methods are studied for the interpolation of elliptical curve by deciding a number of control points as per curvature. The control points can be decided by two ways: a) Minimizing difference between arc length and chord length between two cutter location points. b) Minimizing chordal height between two successive cutter location points on the curve. The novel approach, finding shape error by the intersection of lines, is suggested to determine the number of control points to improve shape accuracy. Variable feed rate is proposed as per the number of control points considering the curvature effect of the tool path. The shape accuracy of elliptical curve of the present approach is compared with the earlier studies and reported.