High-speed precise machine tools spindle units improving

A hybrid high-speed precise machining centre headstock model based on two computation methods: the finite element method (FEM) and the finite difference method (FDM) is presented. The model allows one to calculate precisely the headstock's indices on the basis of which its optimal operating characteristics can be determined. The presented modelling methods allow one to evaluate a design from thermal, stiffness and durability points of view. By way of illustration, the behaviour of three machining centres headstocks with: an electrospindle on rolling bearings, a conventional spindle and an electrospindle on aerostatic bearings are modelled using the hybrid model. The bearing units and cooling system influence on machine tool preciseness has been described.