完全烧结氧化锆陶瓷义齿的超声振动辅助铣削机理研究

With the all ceramic crowns widely used, more and more problems for presintered zirconia ceramics were exposed,such as difficult to control shrinkage,?high fracture rate and so on. These problems severely restricted the development of prosthodontics technology.Base on the material properties and complex surface topography of zirconia ceramic crowns,a new method which used ultrasonic vibration assisted milling zirconia ceramics denture was proposed. In this study,firstly,the formation and propagation mechanism of cracks for machined surface and sub-surface was studied. Secondly,analyzed the influence rules of milling and vibration parameters on machining efficiency,quality and milling force. Thirdly,base on the theory analysis and test,tool wear model and milling force model under the coupling effects for stress and temperature field was built. Meanwhile,fracture properties and wear loss model was built about ultrasonic vibration frequency, amplitude and other parameters, base on the characteristics of denture surface and subsurface Damages. It provided reliable basis for high efficient and low damage milling of denture.Therefore,the traditional machining for zirconia ceramics denture would be changed, prosthodontics medical level will improve overall.

随着全瓷牙和全锆牙的逐步推广，口腔修复领域中大量应用的预烧结氧化锆陶瓷所存在的二次烧结加工工艺复杂、收缩率难以控制、断裂率高等问题严重制约了口腔修复技术的快速发展。本项目针对完全烧结氧化锆陶瓷义齿的材料属性及其复杂的曲面形貌，提出采用超声振动辅助铣削技术来实现其高精高效加工。重点就完全烧结氧化锆陶瓷义齿加工表面宏微观裂纹的形成与扩展机理，超声振动频率、振幅、转速、进给量等工艺因素对加工效率、表面粗糙度及铣削力的影响规律以及义齿边缘碎裂控制方法，并建立加工区域冲击应力场和温度场耦合作用下的铣削力模型。同时，基于义齿超声加工表面及亚表面的损伤特性，建立其断裂性能和磨损量关于超声振动频率、振幅等工艺参数的数学模型。为完全烧结氧化锆陶瓷义齿超声振动辅助切削的高效低损伤加工提供可靠依据，从而改变传统氧化锆陶瓷义齿的加工工艺，全面提高口腔修复的医疗水平。

本项目提出了采用超声振动辅助磨削氧化锆陶瓷义齿的加工方法。阐明了超声振动辅助磨削氧化锆陶瓷的去除机理，掌握了振动参数对磨削力、义齿表面形貌及边缘碎裂的影响机制，提出了超声振动辅助磨削氧化锆陶瓷的磨削力和磨削温度的理论模型。研究了完全烧结氧化锆陶瓷义齿表面及亚表面损伤对其断裂和磨损性能的影响规律。为复杂曲面形貌义齿的高精高效的加工提供了一种新的技术途径，并为该技术在陶瓷口腔修复领域的可行性提供了理论指导和技术支持。