【作者】 雷小宝；

【导师】 廖文和；

【作者基本信息】 南京航空航天大学 ， 航空宇航制造工程， 2012， 博士

【摘要】 近年来随着CAD/CAM技术的不断深入及其在口腔修复领域中的广泛应用，使得修复体制作质量和效率大幅度提升。义齿数控高速加工技术是口腔CAD/CAM技术的关键组成部分，直接关系到义齿加工性能的优劣。由于其形貌复杂，所用材料又多为合金类或陶瓷类等难加工材料，导致其加工过程复杂繁冗，且产品质量难以得到保证。在此背景之下，本文结合义齿临床的应用需求，以预烧结氧化锆陶瓷义齿加工为研究对象，以高速铣削等关键技术为理论支撑，从预烧结氧化锆陶瓷材料的铣削性能及其加工工艺参数设计两个角度出发，系统地研究了高速铣削在义齿加工过程中的相关基础理论、方法及关键技术，并开发了一款小型双主轴四联动高速义齿加工机床。本文的主要研究内容和创新性成果如下：1、深入研究了义齿加工用预烧结氧化锆陶瓷铣削过程中的出口边缘碎裂机理，提出了一种可在加工过程中减小发生出口边缘碎裂的铣削参数优化方法。分析了导致铣削边缘碎裂现象的影响因素并辅以实验。结果表明：不同铣削方式及工件材料的性能参数，例如：硬度、断裂韧性、和微观颗粒的大小，对出口边缘碎裂宽度有较大影响。同时，在铣削中可通过控制铣削参数以达到减小边缘碎裂宽度。2、考虑到义齿成型质量受铣削预烧结氧化锆时刀具的磨损影响较大，采用按照设定等时间间隔的方法，获取了加工过程中刀具的磨损数据，提出了一种基于灰色系统理论的铣削刀具磨损量预报模型，并对刀具磨损量及其寿命进行了预报。通过与实测值的对比分析，验证了模型构建的合理性与准确性。3、基于对球头铣刀几何模型及高速加工切削参数的分析研究，构建了一种基于体积力微元的球头微径铣刀高速铣削力理论模型。系统研究了铣削行间距、进给速度、切削方式、工件形状等因素对义齿加工过程中所产生的铣削力的影响。通过平面铣削参数实验，利用多元正交回归分析法，提出了一种针对预烧结氧化锆陶瓷的铣削力经验预测模型，并采用模拟义齿形貌的变曲率工件铣削实验验证了该模型的合理性。4、给出了一种基于固定效应模型的预烧结氧化锆铣削表面粗糙度析因实验设计方案，研究了主轴转速、径向切削宽度和轴向切削深度等铣削参数对预烧结氧化锆表面粗糙度的影响程度。并运用二次回归正交实验方法，提出了一种针对预烧结氧化锆铣削参数的优化模型。求解出了减小工件表面粗糙度的更佳铣削参数，为优化预烧结氧化锆义齿的加工质量提供了可靠保障。5、基于对预烧结氧化锆瓷块的铣削实验及优化分析结果，选择了合理的义齿高速数控铣削加工参数及加工方式，运用JDPaint软件生成了义齿的铣削刀轨，并对几种刀轨进行了比较分析。在此基础之上，铣削加工出义齿预烧结氧化锆件，对其形貌及表面粗糙度进行检测。通过对测试数据的采集和分析得出义齿表面的加工质量较好，满足口腔医学修复的高精度需求，验证了上述模型构建和优化方法的合理性及可行性。6、基于“椅旁加工”的设计理念，针对义齿加工技术的特点，运用功能分析方法明确了义齿加工装备所需的功能模块，提出了一种面向义齿加工的桌面小型化双主轴四联动数字化制造装备的机械结构，并对其主结构关键部件进行了详细设计及合理布局。考虑到义齿加工对装备结构精度的需求，运用多体系统运动学理论和齐次变换矩阵，构建了该装备结构的空间误差模型，并研究了精度误差的主要来源和影响因素，为保证装备的加工精度提供了理论依据。采用规划的预烧结氧化锆义齿铣削参数，加工出满足口腔修复需求的义齿零件，验证了本装备的性能满足设计的要求。更多还原

【Abstract】 With the development of science and technology, CAD/CAM technologies are graduallyapplied to dental medical treatment, which has greatly improved the quality and efficiency ofdental restoration. The high speed machining (HSM) technology is a key component of dentalrestoration CAD/CAM system for manufacturing denture, which directly related to the quality ofthe workpieces. Due to the complex morphology of denture and hard to machining raw materials(metalic alloy, ceramic), the machining process is complex and the quality is hard to achieved.Considering the demands of dental clinic, the relevant theories and key technologies of HSMused in manufacturing denture are deeply studied in this dissertation based on the experiments.The focuses of the study are the milling performance and machining parameters setting onmilling pre-sintered zirconia ceramics, and designing a digital oral equipment which with twospindles.The main contents and achievements are shown as follows:1. Researching on the phenomenon of exit chipping during in the denture milling on thepre-sintered zirconia ceramics, a new milling method which can dramatically reducing exitchipping has been introduced. The factors leading to phenomenon of exit chipping in millingpre-sintered zirconia has been analysed and verified in several experiments. It’s shown thatdifferent milling and the corresponding performance parameters (rigidity, fracture toughness,micro particle size) of material have effects on exit chipping. The width of exit chipping can bedecreased by optimizing milling parameters.2. Considering the wearing of cutter, milling pre-sintered zirconia has great effect onmachining denture quality; a prediction model of cutter wear has been introduced based on thegray system theory after analyzing the tool wear data collected by the same time interval. Thewearing capacity and lifetime of tool can be forecasted based on this model. The model’s wasverified after analyzing and comparing the measured value in an experiment3. Studying on the geometric model of ball end mill and the high speed cutting parameters,the theory model of high speed milling force in micro-diameter cutter has been established on thebasis ofinfinitesimal of body force. The effets such as radial width of cut, feed rate, cuttingmethods and shape of the workpiece in the milling on cutting force of milling have been studiedsystematically. The empirical prediction model of milling force on machining pre-sinteredzirconia ceramics has been introduced by means of the method of multivariate orthogonalregression to analyse the data of plane milling experiment. The model’s veracity was verifiedaccording to the result of milling experiment about simulate curvature changes in morphology ofdenture.4. On the basis of fixed-effect model, the factorial experiment on surface roughness ofmilling pre-sintered zirconia has been designed, then the effects of milling parameters such as spindle speed, radial width of cut and axial depth of cut have on the surface quality of workpiece.Using quadratic regression orthogonal experiment, an optimizing model has been established tooptimize the milling parameters when machining pre-sintered zirconiao to obtain the bestminimum surface roughness. The model provides reliable guarantees for denture’s machiningusing pre-sintered zirconia.5. Using JDPaint software to generate and analyze milling tool path for machining dentureon the basis ofthe milling experiments and result of optimizing analysis, then selecting therational machining parameters and modes to milling a pre-sintered zirconia denture. Itsmorphology and surface roughness have been observed. The results show good quality for needsof dental restoration in oral medicine. The rationality and feasibility of the aforementioned modelalso been verified by the experiment.6. Designing CNC equipment dedicated for prosthetic dentistry, the characteristics ofdenture processing have been analyzed using functional analysis approach. The mechanicalstructure of the processing system has been set up. The structure of equipment is four-axis withtwo spindles. With a view to compact its structure, the system’s structure also been analysed andoptimized to realized the concept of "the processing next to chair". On the basis of the theory ofMulti-body system and the actual situation of machine tool been studied, the model ofVolumetric error has been deduced and the main resources and affects were analyzed whichprovide the theoretical basis of accuracy.更多还原