面向生物陶瓷人工关节的高压磨料水射流复杂曲面加工机理研究

Every year all over the world, around 40 ~ 60 million people choose to install or replace their artificial joints because of disease, aging issues, etc. Currently, bio-ceramic materials applied to artificial joints have several physical properties, including high hardness, low toughness, high melting point, low thermal conductivity, etc, all of which hinder the traditional fabrication methods to get a flawless product. On the contrary, it is quite easy for traditional fabrication methods to generate flaws like micro cracks on surface, stress concentration, etc, which ultimately will reduce the synthetical fatigue strength of those artificial joint parts. This study aims at using the abrasive water jet machining method to solve the stated intractable issues occurring at the processing of the bio-ceramic materials, in particular, to develop the research of critical complex surface fabrication technique and micro cutting mechanism. Through studying the removal mechanism and abrasive particle erosion mechanism of bio-ceramic materials, we established an abrasive particle erosion estimation model and kinetic model for the complex surfaces. Further, we conducted the process study of the complex surface fabrication technique applied on for bio-ceramic artificial joint using the high pressure abrasive water jet method. Finally, together by developing the matching hardware and software system for the complex surface fabrication with abrasive water jet method, we are able to achieve the high precision, high surface complexity and high fatigue life of micro-miniature fine fabrication technique used on bio-ceramic artificial joint materials. This study will improve the fabrication quality and the synthetic performance of bio-ceramic artificial joint, and also by pushing the cutting edge study of the complex surface fabrication technique with abrasive water jet method, it will provide a novel method for fabricating complex surfaces of other engineering ceramic materials applied in fields like aerospace and other industrial areas .

全世界每年因疾病或衰老等原因更换人工关节的有4000~6000万人。目前，应用于人工关节的生物陶瓷材料，具有高硬度、低韧性、高熔点、低热传导等物理特性，导致加工中极易产生表面微裂痕和应力集中等缺陷，使得零件综合疲劳强度下降。本课题针对生物陶瓷材料加工中存在的如上难点问题，对磨料水射流复杂曲面精加工的关键技术和微观切削机理等方面展开研究。通过生物陶瓷材料去除机理及磨料粒子冲蚀机理研究，建立复杂曲面磨料粒子冲蚀近似模型和动力学模型，结合控制加工质量的关键工艺参数的定量优化和射流冲蚀试验，展开生物陶瓷人工关节磨料水射流复杂曲面的工艺研究。由此，开发复杂曲面磨料水射流加工软硬件系统，实现高精度、复杂曲面、高疲劳寿命的生物陶瓷人工关节微细精加工。研究将提升生物陶瓷人工关节的加工质量和综合性能，推动磨料水射流复杂曲面加工技术的快速发展。为航空航天、工业等领域的工程陶瓷材料复杂曲面的加工提供一种新方法。

针对生物陶瓷人工关节外形结构复杂和机械加工工艺性差等难题，创新提出采用磨料水射流抛光技术对生物陶瓷人工关节进行精加工处理的方法。通过对磨料水射流加工生物陶瓷的冲蚀机理、复杂曲面加工特性和影响加工质量的关键参数定量优化以及对磨料水射流加工系统的动态分析与数学建模等方面的研究，最终实现了对生物陶瓷人工关节的高精度、复杂曲面、高疲劳寿命的精加工。主要研究成果包括：（1）通过提取单颗粒磨料粒子去除材料的运动轨迹，建立了单颗粒磨料粒子冲蚀生物陶瓷的近似切削模型；（2）通过对水射流磨料粒子分布、速度分布和能量分布及相关数学模型的研究，建立了曲面加工动力学模型；（3）通过对磨料水射流抛光工艺的研究，建立了磨料水射流复杂曲面抛光关键工艺参数与加工精度、表面粗糙度之间的关系模型，实现了磨料水射流对生物陶瓷复杂曲面的确定性加工与修形；（4）通过改进现有磨料水射流加工设备，开发了用于生物陶瓷人工关节复杂曲面的磨料水射流加工软硬件系统，包括硬件平台系统、关键工艺参数库、最优工艺及加工路径数据库。本项目的研究成果有助于推动磨料水射流复杂曲面微细加工技术快速发展、提升生物陶瓷人工关节的加工质量和综合性能。同时，也为广泛应用于航空航天、军事、工业等领域的工程陶瓷材料复杂曲面的加工提供了一种新的方法。