Analytic construction and analysis of spiral pocketing via linear morphing

In numerical control, pocketing is a widely extended machining operation with different industrial applications. Conventional strategies (directional and contour parallel) provide a uniform material removal rate, but they show discontinuities and undesirable stops. However, smooth spiral paths overcome discontinuities, although the removal rate is not constant, and their implementation is complex. In order to provide an in-between solution, our algorithm embeds an Archimedean spiral into a linear morphing definition of the pocket. The solution is smooth, simple, analytic, and leads to a B-spline curve. Different tests were performed to compare the proposed spiral to other conventional and spiral strategies. To study the influence of the tool-path geometry, we computed engagement angle and feed direction, and measured force and time. The results demonstrate that our spiral is a committed, analytic and easy to compute solution.