Tool path quasi-static error simulation for a three axes machine tool using multi-body modelling

The improvement of the accuracy of milling machines is a key issue for machine tool manufacturers. Most of them solve the problem designing solutions that are stiffer and with higher damping, this however usually increases the cost of the machine itself. The general idea presented in this paper is to define a strategy for the prediction of the tool path deflection, this will allow a possible correction of the deflection thanks to a post-processing of the NC code. The proposed approach is mainly based on the simulation of the machine behavior and includes the inertia forces due to the axes movement, the gap on the axes, the deflection due to flexibility of the structure and the cutting forces. The model have been assembled using a commercial flexible multi-body software and has been validated thanks to experimental tests. The tuning of multi-body model input variables for tool-path correction has been carried out by a method of error sources synthesis and a DoE approach.