口腔牙冠修复体的旋转超声加工技术研究
毕业论文关键词：旋转超声加工；玻璃陶瓷；牙冠修复体；指数预测模型；切削参数优化
Title Study on the Rotary Ultrasonic Machining of Dental Prosthesis
Abstract This paper carries out the research of processing dental glass-ceramic into crown through the rotary ultrasonic machining. By determining cutting parameters and designing cutting experiment, the of the machined surface on various conditions was measured and the effect of the cutting parameters on cutting force was analyzed. A exponential prediction model of cutting force was builded through the analysis method of multiple regression. By comparing the predicted and experimental values, the relative errors of the model were in an average of 5% or less, which effectively verified the rationality and effectiveness of the constructed model. The cutting parameters were optimized through the particle swarm and penalty function by iterative calculation in MATLAB, which provides a reference for the processing of dental glass-ceramic material. Through the rotary ultrasonic machining, the complete crown restoration was processed successfully on the existing three-axis milling machine by the use of optimized cutting parameters. Keywords: Rotary ultrasonic machining; Glass ceramics; Crown restorations; Exponential Prediction Model; Cutting parameter optimization
目次
1绪论1
1.1研究背景及意义.1
1.2牙科陶瓷材料加工技术的现状.1
1.2.1高速切削加工牙科陶瓷材料的现状1
1.2.2旋转超声技术加工牙科陶瓷材料的现状..1
1.3总结2
2旋转超声加工技术的基本原理.3
2.1引言3
2.2旋转超声加工装置的结构3
2.3旋转超声加工系统的运动学原理4
3旋转超声加工铣削力测量实验.7
3.1引言7
3.2铣削力测量的实验设计及过程.7
3.3铣削力测量结果与分析.9
3.3.1铣削力测量结果..9
3.3.2主轴转速对轴向最大铣削力的影响规律10
3.3.3进给速度对轴向最大铣削力的影响规律10
3.3.4切削深度对轴向最大铣削力的影响规律.11
4旋转超声加工参数优化..12
4.1引言.12
4.2轴向最大铣削力指数预测模型的构建..12
4.3粒子群算法简介..14
4.4铣削力参数优化数学模型.16
4.5玻璃陶瓷切削参数优化实验验证.18
5玻璃陶瓷牙冠的加工19
5.1引言.19
5.2牙冠三文模型建立.19
5.3专用夹具设计20
5.4加工刀轨生成21
5.5实验过程..23
结论25
致谢26
参考文献..27
1 绪论
1.1 研究背景及意义 2008年在全国范围内组织了第三次口腔健康流行病学普查， 最终统计发现，我国有97.6％成年人患有不同程度的口腔疾病，而其中牙齿硬组织疾病占 70％以上。在牙齿疾病频发的现今，再加上科学技术的发展和生活水平的不断提高，人们追求口腔健康特别是牙齿保养的意识得以启蒙和发展，同时对义齿的美观性能和舒适程度也有了进一步的期望[1]。近些年来，拥有出众的机械性能、稳定的化学性质、高度美观的外观效果和优良的生物相容性的新兴材料牙科玻璃陶瓷，受到了国内外医务人员和患者的青睐，在口腔修复领域得以广泛应用[2]。然而，由于玻璃陶瓷材料特有的脆硬性，现有高速切削加工技术使得牙冠产生部分表面及亚表面损伤，例如：表面及亚表面裂纹、变形层、残余拉应力等，无法保证加工精度和质量[3]。此外，由于牙冠修复体属于壁厚约 1mm 的薄壁零件，加工时产生的裂纹稍大，就会在后续加工过程中不断扩展，最终致使工件失效，加工成功率不高。因此如今牙科玻璃陶瓷材料加工的当务之急就是寻找新的既有高效率又能保证加工质量的加工方式。