工程陶瓷特种加工技术的研究现状与进展

工程陶瓷材料具有很高的硬度和强度,耐热性、耐磨性,综合性能优良,已在航空航天、武器、石油化工很多工业领域得到了广泛的应用。概述了近些年工程陶瓷的各种特种加工技术的现状与发展,阐述了各项特种加工技术的基本原理和优缺点,综合分析了工程陶瓷材料加工技术的研究路线,展望了今后工程陶瓷特种加工技术发展前景。     

超高温陶瓷不同型面加工方法的研究

针对超高温陶瓷材料及构件中一些典型型面的加工方法进行了研究,分别列举了深孔、螺纹及异形曲面等典型型面的加工方法和加工工艺,为超高温陶瓷的后续应用提供了技术保障。     

工程陶瓷材料精密磨削加工技术的新发展

本文介绍了陶瓷材料的结构和力学特性，陶瓷材料磨削机理以及当前各种先进的磨削加工方法，为陶瓷材料加工的进一步发展提供了依据。     

ZTM陶瓷材料的平面磨削

氧化锆增韧莫来石（ZTM）是优良的高温结构陶瓷材料。对ZTM陶瓷材料进行磨削加工，研究了其加工性能及加工后表面质量。并与几种典型工程陶瓷材料的磨削加工进行了对比研究。     

电解修整磨削加工在模具材料镜面精加工中的应用

近年来,人们对模具加工技术越来越多地要求形状复杂、高精度及多品种小批量生产。但由于镜面精加工技术发展缓慢,使模具加工业面临着降低模具成本、缩短生产周期等困难。近年来,随着新材料的不断问世,人们已经开展了用铸铁纤维结合剂金刚石砂轮对陶瓷材料进行高能磨削的研究。本文作者最近也采用铸铁纤维结合剂砂轮对钢材的磨削加工开展了研究。现在,钢材不仅限于模具材料,在其它方面的使用率也大大高于陶瓷材料。但是,     

加工陶瓷和半导体材料的新型激光金刚石刀具

西密歇根大学的制造工程教授John Patten博士开发了一种称为“μ-LAM”的微激光辅助加工技术,该方法将激光与金刚石刀具结合起来,对硅半导体和陶瓷材料进行加热软化和切削加工。     

电火花线切割加工Si3N4/TiN纳米复相陶瓷工艺规律的实验研究

分析研究了电火花线切割加工Si3N4/TiN纳米复相陶瓷材料时,影响加工速度和表面粗糙度值的主要因素,得出了各加工参数对加工工艺指标的影响规律,为加工时参数的选择提供了依据.     

工程陶瓷引弧微爆炸加工技术参数分析及性能特点

从系统组成、工作原理、工艺参数、技术特点等方面,介绍了一种新开发的适用于工程陶瓷材料粗加工的引弧微爆炸加工技术,分析了影响加工过程的典型工艺参数,总结了该技术的性能特点。引弧微爆炸加工系统的主要部件为专用脉冲电源及微爆炸发生器,系统工作时生成的微爆炸等离子体射流具有高温高压特性,作用于陶瓷材料表面生成一个圆形蚀坑。加工过程中的工艺参数主要包括喷嘴孔径、工作电流、工作气压、工作脉宽及工作距离。该技术具有低成本、工艺灵活、热损伤小、加工范围广及加工后表面粗糙等特点。     

ZrB_2基超高温陶瓷电火花线切割加工表面粗糙度对其力学性能的影响

采用电火花线切割工艺加工ZrB2基超高温陶瓷,分析了其微观组织变化,研究了不同表面粗糙度对材料抗弯强度和断裂韧性的影响规律,为陶瓷材料的工程化应用奠定了技术基础。     

硼化锆基超高温陶瓷材料电火花加工特性研究

硼化锆基超高温陶瓷材料被广泛用于对轻质、耐高温有特殊要求的领域,但其高硬度、高脆性等特性使其成为难切削材料,在加工该材料的零件时极易磨损工具,缩短工具寿命,使加工变得非常困难,甚至无法切削。采用电火花加工方法对硼化锆基超高温陶瓷材料的加工特性进行了研究,对影响该材料加工特性的工艺参数(电参数、非电参数)进行了系统实验,得出工艺参数对加工特性的影响规律,获得了较高加工速度、能稳定可靠加工的参数范围,以此来指导实际应用。     

工程陶瓷材料的超精加工试验研究

本文分析了陶瓷材料超精加工机理，试验研究了用超精加工工艺参数如磨头压力、振幅、振动频率、工件转速、加工时间等对工件表面粗糙度的影响，得到了一组较优的超精加工工艺参数值，试验结果表明超精加工艺应用于工程陶瓷材料精加工是完全可行的。     

电蚀抛光CVD金刚石膜的实验研究

本文提出了一种新的ＣＶＤ金刚石膜抛光技术。采用该项技术,可以高效率的完成ＣＶＤ金刚石膜的粗抛光。ＣＶＤ金刚石膜表面被预先涂覆一层导电金属,然后采用电蚀方法对该表面进行加工,使金刚石膜突起的尖峰被迅速去除。加工中金刚石表面的石墨化使电蚀加工得以不断延续。通过单脉冲放电试验已经发现涂覆层的材料对金刚石膜的加工效果有很大影响。与普通金属加工相比,金刚石膜的电蚀过程有其完全不同的特征。通过试验和分析,本文还对金刚石膜的电蚀去除机理进行了初步探讨。     

陶瓷基复合材料加工技术及其表面亚表面损伤机制研究进展

综述了陶瓷基复合材料的传统机械加工、超声辅助加工、激光加工、多能场复合加工等加工方式的研究进展,并简述了几种加工方式的优缺点.对陶瓷基复合材料的表面及亚表面损伤机制进行了总结和分析,包括材料表面亚表面损伤形式、材料表面亚表面理论及模型研究.提出了传统的陶瓷基复合材料加工技术需要进一步优化刀具材料、开发新的刀具结构、优化工艺参数等,以减少加工缺陷.研究了复合加工中材料去除率最大条件下的损伤容限条件、材料加工后的性能保持性等,同时探究了高效高质量的多能场复合加工新方法及其应用理论,以及研究探索了在复杂载荷及动载荷(如动态切削力、高温切削及超声动态冲击载荷)耦合作用下陶瓷基复合材料的内在损伤机理及演化问题.     

Development of Technology and Strategies for the Machining of Ceramic Components by Sinking and Milling EDM

This paper investigates the manufacturability of B₄C, SiC, Si₃N₄-TiN by milling EDM and the performance of it has been compared to conventional sinking EDM. It is shown that due to the good flushing conditions, milling EDM performs well, even for the machining of ceramic materials with a rather low electrical conductivity (B₄C, SiC). Because the used milling EDM technique removes material in a layer by layer fashion (2D-machining), a new strategy for the machining of complex 3D-shapes in ceramic material has been developed. It consists of a milling EDM pre-machining step, followed by one or more finishing sinking EDM steps. The developed strategy has been validated on an industrial example and compared to a pure sinking EDM strategy. Time reductions of more than 50% were obtained.     

陶瓷磨削的材料去除机理

磨削是目前工程陶瓷的主要加工方法,为了开发新的高效、低成本、低损伤加工陶瓷的方法,需要更深入地揭示其加工机理。本文介绍了陶瓷磨削的材料去除机理方法的研究进展,就其进行了一定的讨论,并得出相关的结论。     

陶瓷墙地砖磨削加工研究进展

我国已成为陶瓷墙地砖生产大国，加工陶瓷墙地砖的金刚石工具的发展就显得尤为重要。本文全面介绍了陶瓷墙地砖的基本性能和分类，加工工艺过程，以及相关金刚石工具的制造工艺。讨论了近年来在陶瓷墙地砖磨抛加工磨削机理、加工工艺、磨具和金刚石工具的最新研究成果，并提出了今后研究的设想。     

Surface integrity and material removal mechanisms associated with the EDM of Al2O3 ceramic composite

Electric discharge machining (EDM) has been proven as an alternate process for machining complex and intricate shapes from the conductive ceramic composites. The performance and reliability of electrical discharge machined ceramic composite components are influenced by strength degradation due to EDM-induced damage. The success of electric discharge machined components in real applications relies on the understanding of material removal mechanisms and the relationship between the EDM parameters and formation of surface and subsurface damages. This paper presents a detailed investigation of machining characteristics, surface integrity and material removal mechanisms of advanced ceramic composite Al₂O₃–SiC_w–TiC with EDM. The surface and subsurface damages have also been assessed and characterized using scanning electron microscopy (SEM). The results provide valuable insight into the dependence of damage and the mechanisms of material removal on EDM conditions.     

Electroconductive ceramic tooling for dry deep drawing

Large use and waste of lubricating oil has become a very serious environmental issue. Hence, oil-free metal forming is one of the most promising solutions to this issue. Among them, ceramic tooling is proposed because of its good tribological properties. Its feasibility for dry deep drawing has been studied in laboratory; ceramic tooling is thought to be applicable to dry deep drawing. However, the workability of ceramics in tooling preparation is inferior to that of alloy tool steel. In the present paper, electroconductive ceramics are proposed as an alternative tool material. The electroconductive ceramic tooling is shaped by electric discharge machining such as wire electric discharge machining, die sinking electric discharge, and so forth; any shape of tools can be easily accommodated by these methods. The workability of electroconductive ceramics by electric discharge machining as well as the deep drawability with electroconductive ceramics tooling is experimentally evaluated. Selection of electric conditions for electric discharge machining influences the surface finish quality of electroconductive ceramics. Zirconia-based electroconductive ceramic die has an equivalent deep drawability in dry to conventional SKD11 die with lubricant.     

Wear behavior of Al2O3/Ti(C,N)/SiC new ceramic tool material when machining tool steel and cast iron

Design, fabrication and application of ceramic cutting tools are one of the important research topics in the field of metal cutting and advanced ceramic materials. In the present study, wear resistance of an advanced Al₂O₃/Ti(C,N)/SiC multiphase composite ceramic tool material have been studied when dry machining hardened tool steel and cast iron under different cutting conditions. Microstructures of the worn materials were observed with scanning electronic microscope to help analyze wear mechanisms. It is shown that when machining hardened tool steel at low speed wear mode of the kind of ceramic tool material is mainly flank wear with slight crater wear. The adhesion between tool and work piece is relatively weak. With the increase of cutting speed, cutting temperature increases consequently. As a result, the adhesion is intensified both in the crater area and flank face. The ceramic tool material has good wear resistance when machining grey cast iron with uniform flank wear. Wear mechanism is mainly abrasive wear at low cutting speed, while adhesion is intensified in the wear area at high cutting speed. Wear modes are dominantly rake face wear and flank wear in this case.     

On the mechanism and mechanics of material removal in ultrasonic machining

Precision abrasive machining processes such as ultrasonic machining are commonly employed to machine glasses, single crystals and ceramic materials for various industrial applications. Until now, precision machining of hard and brittle materials are poorly investigated from the fundamental and applied point of views. Taking into account the major technological importance of this subject to the production of functional and structural components used in high performance systems, it is often desired to estimate the machining rate for productivity while maintaining the desired surface integrity. The success of this approach, however, requires not only the fundamental understanding of the material removal on the microstructural scale but also the relationship between the machining characteristics and material removal rate in ultrasonic machining. In this study, the ultrasonic machining of glass was investigated with respect to mechanism of material removal and material removal rate (with basic machining parameters) with a mild steel tool using boron carbide abrasive in water as slurry. The analysis indicates that the material removal was primarily due to the micro-brittle fracture caused on the surface of the workpiece. For micro-brittle fracture mode, the relationship for the material removal rate, considering direct impact of abrasive grains on the workpiece, based on a simple fracture mechanics analysis has been established. The effect of machining conditions on material removal rate has been discussed. This research provides valuable insights into the material removal mechanism and the dependence of material removal rate on machining conditions and mechanical properties of workpiece material in ultrasonic machining.