工程陶瓷的热力效应微细加工技术研究

发布时间：2018-03-30 03:08

本文选题：工程陶瓷　切入点：电化学放电复合磨削加工　出处：《江苏大学》2017年硕士论文

【摘要】：随着科学水平的进步,微型机电系统(MEMS)得到了迅猛的发展,特别是近几年,MEMS器件的需求与日俱增,以工程陶瓷为代表的绝缘高硬脆材料具有非导电、耐高温、耐腐蚀、高硬度等特性,在MEMS中的应用越来越广泛。尤其是对于高温、强腐蚀、强振动等极端恶劣的工作环境,采用工程陶瓷材料加工出的零件完全可以满足使用要求。然而,以氧化铝陶瓷为代表的工程陶瓷材料具有高熔点、高硬脆的特点,对其进行微细加工非常困难。目前,对工程陶瓷等绝缘高硬脆材料主要采用超声加工、磨料水射流加工、电化学放电加工和激光加工等特种微细加工方法。本文为了得到更高的加工效率、更好的加工质量,主要对电化学放电复合磨削加工和皮秒激光加工氧化铝工程陶瓷开展了深入研究,并通过分析热力效应的作用,对两种加工技术的效果进行了对比。主要研究内容如下:1.研究了电化学放电复合磨削加工工程陶瓷的机理。重点分析了工具电极表面气层的形成过程,探讨了电化学放电加工去除材料主要是通过火花高温热蚀和化学腐蚀,并建立了火花作用下的温度模型。结合电化学放电加工原理和金刚石磨粒磨针加工工程陶瓷原理,研究了工程陶瓷表面被火花放电高温软化,再通过金刚石磨粒进行塑性磨削的过程。2.构建了电化学放电复合磨削加工试验装置,在氧化铝工程陶瓷上展开了微孔加工试验。采用单变量控制法,研究了脉冲电压或加工频率与微孔形貌、微孔深度、微孔进口直径和加工速率的规律。试验结果显示:脉冲电压越高或者加工频率越低,加工速率就会越高,加工出的微孔极限深度越深,但是微孔进口直径越大且微孔周围形貌越差。3.用皮秒激光设备对氧化铝工程陶瓷进行了微孔加工试验。探讨了皮秒激光加工氧化铝工程陶瓷的机理,然后介绍试验装置并进行加工试验,研究了扫描路径、激光输出功率、激光重复频率、扫描速度和扫描次数等工艺参数与微孔形貌、微孔进口直径、微孔深度之间的规律。并将BP神经网络和遗传算法融合后,应用于皮秒激光加工的工艺参数优化中,快速、准确地寻得了目标微孔进口直径所对应的工艺参数组。4.对电化学放电复合磨削加工和皮秒激光加工的微孔进口形貌、孔内壁的表面粗糙度、加工孔的形状精度和孔周围的加工残渣等进行了对比分析。由于热力效应的作用方式不同,皮秒激光加工的微孔进口圆度较好;电化学放电复合磨削加工出的微孔内部较为光滑,基本无锥度,孔周围无杂质残留。本文所研究的电化学放电复合磨削加工技术具有装置简单、加工成本低和加工柔性好等优点;皮秒激光加工技术具有加工效率高、操作简便和加工柔性好等优点。它们都属于微细制造领域内的特种加工技术,能有效的对工程陶瓷等绝缘高硬脆材料进行微细加工,应用前景非常广阔。
[Abstract]:With the development of science, MEMS (Micro Electromechanical system) has been developing rapidly, especially the demand of MEMS devices has been increasing in recent years. The insulating high-hard brittle materials, represented by engineering ceramics, have non-conductive, high temperature and corrosion resistance. High hardness and other properties are more and more widely used in MEMS. Especially for the extremely bad working environment such as high temperature, strong corrosion and strong vibration, the parts made of engineering ceramics can completely meet the requirements of application. The engineering ceramic materials, such as alumina ceramics, have the characteristics of high melting point and high hardness and brittleness, so it is very difficult to micro-process them. At present, ultrasonic machining and abrasive water jet machining are mainly used for engineering ceramics and other insulating high-hard brittle materials. In order to obtain higher machining efficiency and better machining quality, electrochemical discharge machining and laser machining are special micro-machining methods. The electrochemical discharge composite grinding and picosecond laser processing of alumina engineering ceramics were studied, and the effect of thermal effect was analyzed. The effects of the two machining techniques are compared. The main research contents are as follows: 1. The mechanism of electrochemical discharge composite grinding for engineering ceramics is studied. The formation process of gas layer on the surface of tool electrode is analyzed. The removal of materials by electrochemical discharge machining is mainly through high temperature thermal erosion and chemical corrosion by spark, and the temperature model under the action of spark is established, which combines the principle of electrochemical discharge machining and the principle of diamond abrasive grinding needle machining engineering ceramics. The surface of engineering ceramics was softened by spark discharge at high temperature, and the process of plastic grinding by diamond abrasive particles was studied. Micropore machining experiments were carried out on alumina engineering ceramics. Pulse voltage, machining frequency, micropore morphology and micropore depth were studied by single variable control method. The experimental results show that the higher the pulse voltage or the lower the machining frequency, the higher the machining rate and the deeper the limit depth of the micropore. However, the larger the inlet diameter of the micropore is and the worse the morphology around the micropore is. 3. The micropore processing test of alumina engineering ceramics with picosecond laser equipment is carried out. The mechanism of picosecond laser processing of alumina engineering ceramics is discussed. Then the experimental device was introduced and the processing test was carried out. The process parameters, such as scanning path, laser output power, laser repetition rate, scanning speed and scanning times, were studied, such as the morphology of micropores, the inlet diameter of micropores, and so on. Combining BP neural network with genetic algorithm, it is applied to the optimization of technological parameters of picosecond laser processing. The process parameters corresponding to the inlet diameter of the target micropore are found accurately. 4. The inlet morphology of the micro hole and the surface roughness of the inner wall of the hole are obtained for electrochemical discharge composite grinding and picosecond laser machining. The shape accuracy of the machining hole and the machining residue around the hole are compared and analyzed. Due to the different thermal effect, the microhole inlet roundness of picosecond laser processing is better. The micro-hole machined by electrochemical discharge composite grinding has a smooth interior, no taper and no impurity around the hole. The electrochemical discharge composite grinding technology studied in this paper has a simple device. The picosecond laser processing technology has the advantages of high processing efficiency, easy operation and good processing flexibility. They all belong to the special processing technology in the field of micro manufacturing. It can be used in micro-machining of high-hard and brittle insulating materials such as engineering ceramics, and its application prospect is very broad.
【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ174.6

【参考文献】