Tool wear induced error avoidance on dental prosthesis manufacturing

Abstract

During the manufacturing of dental prostheses, tight tolerances have to be obtained in order to ensure the correct fitting of the prosthesis seats to the implants located on the patient’s jaw. However, the wearing of the tool can generate errors during precision milling processes that lead to unacceptable geometrical deviations, producing a high cost due to the waste of resources and machine time. The present paper introduces a procedure for the avoidance of these defects during the precision milling processes employed for the machining of dental prostheses. By the use of geometrical models, the deviations generated on the machined surfaces by a worn tool can be calculated in comparison to a fresh tool. Once the deviations are calculated, it is possible to avoid them by the use of 2D tool radius compensation techniques. The capability of the solution presented here was validated by machining prosthesis seats and evaluating their assembly to a fitting part. The obtained results show that the developed solution is capable of eliminating the fitting strains generated when machining dental prosthesis seats with a worn tool.