Abstract
Abstract
A computer simulation of plunge centreless grinding is presented. The key assumption is that the forces on the workpiece equilibrate fast enough to treat the process as a sequence of equilibrium states. Equilibrium forces are calculated at each time step, allowing machine and contact deflections to be accounted for when imposing compatibility upon the workpiece. Machine deflections of the grinding wheel, workblade, and regulating wheel are assumed proportional to the applied forces, with constants obtainable from independent experiments. Contact deflections are calculated with a Hertzian analysis and known material properties. Empirical data relating grinding force to actual depth of cut iteratively ‘close the loop’ between equilibrium and compatibility. Results of the simulation technique include histories of the workpiece shape, apparent and actual depths of cut, all forces on the workpiece, and all contact and machine deflections. It is shown that regenerative lobing is influenced by the specific grinding energy, and that actual depth of cut might be much lower, and specific grinding energy significantly higher, than in comparable surface grinding processes. It is pointed out that the application of additional, known forces to the top of the workpiece could allow equilibrium and compatibility in centreless grinding to be controlled.