Modeling of curved diamond wheel errors for improvement of freeform grinding accuracy

A superhard diamond grinding can machine the hard and brittle freeform workpiece, but it is difficult to control the form-truing errors of curved wheel-profile in multiaxial grinding. Generally, it needs multiple compensation grindings through the on-machine measurement of the ground surface, leading to inefficiency. Hence, the model of 2D wheel-profile errors is proposed to directly compensate for 3D curved wheel errors in automatic grinding. This is because the wheel-profile form-truing errors mainly influence the ground freeform errors. The objective is to improve the freeform accuracy without inefficient measurement-to-compensation in the grinding system. First, the on-machine form-truing of the torus-shaped diamond wheel was employed in freeform grinding; then, the form-truing errors were systematically analyzed in connection to the ground freeform errors. It is shown that the curved form-truing errors may be parameterized by the dresser width, the wheel-profile width, and the wheel-profile in the case of large wheel positioning error. The simulated results also display that the freeform form errors decrease by increasing the wheel-profile curvature and decreasing the workpiece curvature in the case of same form-truing errors. Moreover, the simulated wheel-profile errors may directly be compensated to freeform grinding without any on-machine measurement.