Spiral tool path generation method for complex pocket machining based on electrostatic field theory

Because its unique advantages, such as constant cutting direction, gradually changed cutting width, less tool retractions and less sharp turnings, spiral tool path has been a preferred option in 2.5D pocket milling. However, most of existing spiral tool path generation strategies are based on geometric algorithm, it is often difficult for them to simply handle the problems of no residue, smooth and efficient at the same time. This study presents a spiral tool path generation method for complex pocket machining based on the theory of electrostatic field to improve machining performance. The pocket is gridded and divided into grids based on pocket boundary and medial axis transformation (MAT). Specific boundary conditions of finite element equation are defined and processed according to the needs of boundary and MAT of pocket. The original contour parallel tool path is thus obtained based on the Laplace’s equation of electrostatic field. The numerical results obtained using extensive simulation indicate that the proposed method can effectively generalize spiral tool paths for pockets with or without islands. Empirical comparisons show that the proposed method performs better than existing approaches in spiral tool path generation, while also providing the capability of pocket decomposition method that is very useful for pockets with multi-island. A demonstrative machining example is provided.