Research On Efficient Toolpath Optimization For Dental Restoration

With the improvement of social technology, the concept of “dental restoration” has brokenthough the meaning of “prosthodontics”. Not only the matching and occlusion of the false teeth isasked, but also the machining efficiency and the machining precision are being put forward. However,the tool path design of dental restoration is one of the key elements to accomplish the machiningprocess. Based on the traits of the dental restoration, in order to meet the needs of the actualmachining, some related algorithms are proposed in this paper.(1) The contour parallel tool path, based on the medial axis, is proposed to achieve the dentalrestoration machining. At first, the contour points are classified to convex and concave points, andthen the corresponding angle bisectors are computed to get the medial axis. On the basis of the medialaxis, the subregion is introduced to compute the tool path. The high quality tool path could be gottenthough this algorithm.(2) In order to realize the tool path trasition smoothly, the Bspline and double arc trasition arebrought to optimize this problem. The Bspline curve is used to connect the transistion from fatherloop into the son loop, and the double arc link is used to connect the trasisition from the son loop backinto the father loop. The speed of the transition could be kept stability during the machining process,which could improve the machining efficiency.(3) The corner trasition of the tool path is being reaserched in this paper. In order to optimize theconer tool path, three clothoid curves are jointed to realize the trasition. First, the skeleton line isbeing used to get the residual area during the machining. And then some appropriated points arechoosed to control the jointed curves. Thouth this designed trasition, the speed and the accelaraion arekept stablitiy, which could improve the machining precision and efficiency.(4) To solve the machining path planning of multiple dental restorations, the machining model andits connected points are adjusted several times in this paper. Firstly, genetic algorithm, which solvesthe sequence of the geometrical center of the machining model, is proposed to plan the generalmachining route of the multiple models. Then the posture and the start point of the machining modelare transformed to shorten the machining length between adjacent models. The experimental resultsshow that this method can effectively minimize the overall processing length.