电火花磨削非导电工程陶瓷实验研究

针对非导电工程陶瓷的加工难题,提出了双电极同步伺服电火花磨削新方法,并用不导电的Al2O3工程陶瓷进行了加工实验,研究了脉冲宽度、脉冲间隔、峰值电压、峰值电流等电参数对材料去除率和表面粗糙度的影响规律,并进行了理论分析.实验结果表明,在实验加工的范围内,脉冲宽度的增加、峰值电压的升高、峰值电流的增大、脉冲间隔的降低都能使材料去除率升高,而对表面粗糙度的影响则不尽相同.     

绝缘陶瓷电火花磨削加工的研究

针对绝缘陶瓷的磨削加工问题，提出了基于绝缘陶瓷辅助电火花加工原理的绝缘陶瓷电火花磨削加工方法。介绍了绝缘陶瓷材料的电火花磨削加工原理，对绝缘陶瓷Si3N4进行了电火花磨削加工工艺试验，研究了电参数对绝缘陶瓷Si3N4电火花磨削加工速度的影响，进行了微细轴电火花磨削加工试验，加工出了直径1mm的Si3N4绝缘陶瓷微细轴。     

Al2O3陶瓷电火花磨削工作液实验研究

考虑到工作液对于非导电工程陶瓷双电极同步伺服电火花磨削新工艺的重要性,以氧化铝陶瓷加工为例,通过实验的方法研究了工作液的种类、浓度对材料去除率和加工表面粗糙度的影响规律,给出了实验步骤,并对实验结果进行了理论分析。综合考虑加工效率、加工质量、成本及环保等因素,在自来水中配制5%体积浓度的DX-1乳化液是比较理想的工作液。考虑单一效果,在自来水乳化液加入0.5%质量的聚乙烯醇作工作液可以提高材料去除率10%以上;使用去离子水作工作液可以得到最好的表面质量。     

非导电陶瓷特种加工复合磨削技术

概述了国内外非导电陶瓷磨削加工技术的研究进展.对延性域磨削和半延展性磨削、在线电解修整磨削、电化学在线控制修整磨削等精密、超精密磨削加工技术及超声波辅助磨削、激光预热辅助磨削、机械电解电火花复合磨削、电火花磨削等特种加工复合磨削技术的原理、特点进行了分析评述.提出了非导电陶瓷的电火花诱导可控烧蚀磨削加工技术,并介绍了其...     

基于灰色关联理论的RB-SiC陶瓷电火花机械复合磨削工艺参数优化

开展反应烧结碳化硅陶瓷电火花机械复合磨削试验，分析砂轮参数、磨削参数以及放电参数对陶瓷表面粗糙度、材料去除率、砂轮磨损率以及法向磨削力的影响规律。结果表明:与普通磨削相比，电火花机械复合磨削能提高RB-SiC陶瓷的材料去除率，且有效降低磨削时的法向磨削力；但过高的放电能量会造成砂轮的严重磨损，导致材料去除率和磨削表面质量降低。基于灰色关联理论和正交试验对工艺参数进行优化，并开展试验对优化结果进行验证。结果表明:优化后的工艺参数能有效提高材料去除率和磨削表面质量，并降低法向磨削力和砂轮磨损率。      

基于遗传算法的工程陶瓷电火花加工技术

工程陶瓷材料硬脆、导电率低,难以获得高效精密的电加工效果.本文针对工程陶瓷电火花加工特点,在分析国内外工程陶瓷电火花加工技术的基础上,提出了基于遗传算法的工程陶瓷电火花加工方法.该方法结合遗传算法、神经网络及模糊控制理论构造了多环式自适应控制系统,在线对加工过程进行断丝预防、加工工艺自适应和加工参数自适应监测与控制,从而为难加工材料实现高效精密的电火花加工提供理论与技术指导.     

混粉电解电火花复合加工工艺研究

在电解电火花加工技术的基础上,提出了在电解液中加入导电粉末加工非导电材料的新方法。通过对高硼硅玻璃非导电材料进行混粉电解电火花加工实验,对加工过程中各影响参数(电压、电解液浓度、粉末浓度)进行分析,结果表明:采用混粉电解电火花加工技术可高效地加工脆硬非导电材料的表面,并能获得较好的表面质量。     

聚晶金刚石电火花磨削试验的人工神经网络建模

聚晶金刚石(PCD)由于具有高硬度、高耐磨性和抗腐蚀性等优良的特性,其应用范围日益广泛,但是其成型加工非常困难。目前,聚晶金刚石常用的加工方法有机械研磨和电火花磨削,由于机械研磨效率低、金刚石层厚度不均匀等缺点,其应用受到很大限制。而电火花磨削工艺加工效率高,PCD平面度易于控制,近年来得到了迅速的发展。电火花磨削工艺主要参数如工件极性、脉冲宽度、脉冲间隔、峰值电压和峰值电流对工艺指标金刚石材料去除率(MRR)均有影响,而一般的方法难以确定工艺参数与工艺指标的关系,本文建立了电火花磨削参数和金刚石材料去除率的人工神经网络模型,该模型对未知工艺条件下的预测结果最大误差为14．29％,基本满足工程实际的需要。     

石墨电极电火花加工非导电陶瓷SiO2实验研究

以导电胶涂层作为辅助电极、石墨作为工具电极,用实验的方法考察了电火花加工非导电陶瓷SiO2的可行性;证明在正极性加工条件下,石墨电极能增强导电膜生成,提高加工稳定性;并给出了脉冲宽度、加工电流等电参数对加工速度、电极损耗及表面质量等工艺指标的影响规律,得出了一些有益的结论.     

纤维强化陶瓷复合材料的电火花加工

陶瓷基复合材料密度低,在高温下仍保持高强度,被认为是下一代先进的航空航天材料,但对其加工却十分困难。采用电火花方法加工一种连续陶瓷纤维强化陶瓷基复合材料,并比较排屑条件对加工性能的影响。为深入研究加工工艺,使用正交试验研究了极间电压、峰值电流、脉宽和占空比等工艺参数对材料去除率的影响,同时进行了方差分析。通过分析预测了最优加工条件,并通过试验进行验证。结果表明:采用电介质深冲的电火花加工可促进排屑,材料去除率提高了约80%;采用高极间电压和小占空比可显著提高加工效率。试验还发现这类复合材料电火花的主要去除方式是基体材料热扩散导致的裂纹和绝缘纤维的断裂。     

Review on ultrasonic machining

Ultrasonic machining is of particular interest for the cutting of non-conductive, brittle workpiece materials such as engineering ceramics. Unlike other non-traditional processes such as laser beam, and electrical discharge machining, etc., ultrasonic machining does not thermally damage the workpiece or appear to introduce significant levels of residual stress, which is important for the survival of brittle materials in service. The fundamental principles of ultrasonic machining, the material removal mechanisms involved and the effect of operating parameters on material removal rate, tool wear rate and workpiece accuracy are reviewed, with particular emphasis on the machining of engineering ceramics. The problems of producing complex 3-D shapes in ceramics are outlined.     

Probability of precision micro-machining of insulating Si3N4 ceramics by EDM

Electrical discharge machining (EDM) is used as a precision machining method for the electrically conductive hard materials with a soft electrode material. But recently we succeeded to machine on insulating material by EDM. The technology is named as an assisting electrode method. The EDMed surface is covered with the electrical conductive layer during discharge. The layer holds the electrical conductivity during discharge. For micro-EDM, the wear of tool electrode becomes lager ratio than the normal machining. So the micro-machining is extremely difficult to get the precision sample.

In this paper to obtain a fine and precise ceramics sample, some trials were carried out considering the EDM conditions, tool electrodes material and assisting electrode materials. Insulating Si₃N₄ ceramics were used for workpiece. The machining properties were estimated by the removal rate and tool wear ratio. To confirm the change of micro-machining process, the discharge waveforms were observed. The micro-machining of the Ø0.05 mm hole could be machined with the commercial sinking electrical discharge machine.     

Study of electrical discharge grinding using metal matrix composite electrodes

An investigation was made into the combined technologies of electrical discharge machining and grinding (EDMG). A metal matrix (Cu/SiC_p) electrode with a rotating device was made and employed to study the EDMG technology. It was found that 3–7 times the normal electrical discharge machining (EDM) material removal rate (MRR) could be achieved in EDMG under suitable conditions of electrode rotating speed, SiC_p particle size and current. This novel achievement is attributed to the fact that, under appropriate conditions, the hump-shaped melted material created by the EDM mechanism is vulnerable to attack by the grinding mechanism during the EDMG operation, greatly increasing the removal rate. Conversely, under inappropriate conditions, in which hump-shaped material solidifies prior to the non-conductive ceramic particle grinding, the above function becomes negligible and results in much lower MRR.     

钛铝合金电火花加工工艺参数影响实验

为研究钛铝合金电火花加工工艺参数对材料去除率的影响,通过四因子二水平的全因子析因实验,确定了材料去除率的显著影响因子为电极极性、脉宽、占空比和峰值电流。通过最陡上升路径法,找到了材料去除率最大值对应的参数范围,并以此为基础设计中心复合响应曲面实验,得到了材料去除率的拟合公式,计算出材料去除率理论最大值及其对应的加工参数。实验验证了材料去除率拟合公式的正确性,并给出材料去除率拟合公式适用的参数范围。     

田口-灰关联法应用于Inconel 718微放电铣削参数最佳化(英文)

应用田口-灰关联法对Inconel 718微放电铣削多重质量特性如电极消耗率、材料去除率和扩口量进行最佳化,分析放电电流、脉冲时间、休止时间和极间间隙对加工Inconel 718之电极消耗率、材料去除率和扩口量的影响。实验结果表明,以最佳微放电铣削参数进行加工,其电极消耗率由5.6×10-9mm3/min降低到5.2×10-9mm3/min,材料去除率由0.47×10-8mm3/min增加到1.68×10-8mm3/min,扩口量由1.27μm降低到1.19μm。研究结果显示,应用田口-灰关联法,可以改善微放电铣削多重质量特性。     

Effect of machining fluid on the process performance of electric discharge milling of insulating Al2O3 ceramic

Wire electric discharge machining (WEDM) and electrical discharge machining (EDM) promise to be effective and economical techniques for the production of tools and parts from conducting ceramic blanks. However, the manufacturing of insulating ceramic blanks with these processes is a long and costly process. This paper presents a new process of machining insulating ceramics using electrical discharge (ED) milling. ED milling uses a thin copper sheet fed to the tool electrode along the surface of the workpiece as the assisting electrode and uses a water-based emulsion as the machining fluid. This process is able to effectively machine a large surface area on insulating ceramics. Machining fluid is a primary factor that affects the material removal rate and surface quality of the ED milling. The effects of emulsion concentration, NaNO₃ concentration, polyvinyl alcohol concentration and flow velocity of the machining fluid on the process performance have been investigated.