New fabrication system of prostheses using numerically controlled electric discharge machining

将电火花加工(EDM)技术应用于假体制造。电火花加工的三个应用领域分为辅助使用、直接制造牙冠和桥体以及使用CAD/CAM工艺制造钛覆盖件。研究了数控冲压式和线式电火花加工在钛铸件上制造精密附着体的方法，并发现这些用途是实用的。另一方面，利用最新研制的激光数字化铣床对柱塞式电火花加工电极的CAD/CAM加工进行了研究。用柱塞式电火花加工钛时，由于电极的磨损，需要多次更换电极才能达到足够的加工精度。此外，还利用新开发的数字化机床和铣床研究了直接用CAD/CAM工艺制造牙冠的问题。这些结果表明，所研究的新技术具有广阔的应用前景。

Electric discharge machining (EDM) was applied in the fabrication of prostheses. The three areas of use of EDM are classified as supplementary use, direct fabrication of crowns and bridges and fabrication of titnium copings using a CAD/CAM process. Numerically controlled (NC) ram type and wire type EDM were investigated to fabricate precision attachments on titanium castings and these usages were found practical. On the other hand, fabrication of electrodes for the ram type EDM with a CAD/CAM process was investigated using a newly developed laser digitizer and milling machine. Graphite electroles with boty abutment and coronal shapes were fabricated and supplied for machining titanium using ram type EDM.The wear of electrodes was a problem and we had to change electrodes many times to achieve enough accuracy. Furthermore, fabrication of crowns directly with a CAD/CAM process was also investigated using newly developed digitizer and milling machine. These results indicated new technolagies investigated are promising in the future.