Models for stiffness characterization of the spindle-chuck system in a CNC lathe for prediction of deflections in CAPP

Precision machining of components with tight tolerances requires not only to do a fine presetting of tools, but also to carry out on-line tool-path corrections in order to compensate the form deviations that arise in the workpiece derived from the action of cutting forces. Advanced and expensive technology, such as machine-tools equipped with multiple sensors, are commonly utilized for this purpose. However, if an early prediction of deviations were analyzed, it would be possible to take them into account in planning stages so that necessity for on-line compensations would be minimized. With this purpose, two math models based on strain energy analysis and a FEM model are proposed in this work and compared each other and also with respect to experimental machining tests, showing satisfactory coincidence of results.