Three and five axes milling of sculptured surfaces

The aim of this work is the analysis of the influence of the milling parameters on the surface finish. This work is of interest to both science and industry. On one hand, it tries to reduce the manual polishing time, which represents a high percentage of the production time of moulds. On the other hand, while the literature mainly refers to steel moulds, this work was carried out on aluminium because of its advantages for machining and its suitability for moulds. In small batch production the manufacturers are interested in the production of aluminium moulds. A 5 axis CNC milling machine was used for the surface finishing of several parts, previously 3 axis machined, within equal cutting conditions. Different machining conditions on 3 and 5 axes finishing operations were tested. The comparison of the results allows to conclude that a better surface finish is achieved with 5 axis milling using an end mill inclined in the feed instead of the traditional 3 axis milling with a ball nose cutter. The application of the Design of Experiments technique together with multiple linear regression enables the establishment of a mathematical model of the process that gives the process parameter values that lead to the minimum machining time in order to achieve a certain roughness.