Investigation on path optimization and look-ahead speed control algorithm during numerical control grinding of dentures of glass ceramics

The processing efficiency of dentures is generally quite low due to the complex profile form and high brittleness of the dentures. However, there is little research for efficient path optimization and look-ahead speed control algorithm in denture machining field, which hinders the improvement of the machining efficiency and denture quality. In this work, an optimization method for both straight transition and curve paths was proposed, and look-ahead speed control algorithms for different machining paths were designed. The anomalous points were deleted according to the preprocessing algorithm before the path optimization. The straight transition path and curve path were fitted by the quasi-parabola model and cubic B-spline curve, respectively. The error between the optimized path and original path was analyzed, and the results demonstrated that the path optimization methods were reliable. A look-ahead speed control model based on S-type speed control was proposed, and the boundary conditions for different paths were calculated. The simulated and experimental results indicated that optimized algorithm significantly improved the machining efficiency and reduced the vibration of the machine tool. The accuracy and surface roughness of the denture processed using the optimized algorithm met the medical standard. This work can provide a theoretical guidance for high-efficiency and precision machining of dentures of glass ceramics.