Tool path generation via the multi-criteria optimisation for flat-end milling of sculptured surfaces

Abstract

A method of generating optimal tool paths for sculptured surface machining with flat-end cutters is presented in this paper. The inclination and tilt angles, as well as the feed directions of the cutter at each cutter contact point on a machining path are optimised as a whole so that the machining width of the tool path can be as large as possible, and concerns such as smooth cutter motion, gouging avoidance, scallop height and machining widths overlap are also considered when calculating a path. A multi-criteria tool path optimisation model is introduced, and it is converted into a single objective optimisation with the weighted sum method. The Differential Evolution (DE) algorithm is suitable for solving this highly non-linear problem. However, the searching process of the DE algorithm may be trapped in local minima due to large number of design variables. Therefore, an algorithm combining the DE algorithm and the sequence linear programming algorithm is developed to solve this optimisation model. The proposed method is applied to two freeform surfaces to illustrate its effectiveness.

Keywords:

• sculptured surface machining
• multi-criteria optimisation
• tool path
• smooth cutter motion
• flat-end cutter

Funding

This work was supported by National Natural Science Foundation of China [grant number 51325502] and Science & Technology Commission of Shanghai Municipality [grant numbers 13JC1408400, 14111104801].