特种加工技术的最新进展和研究热点

综述了特种加工技术的最新进展，简要介绍了电火花加工、电化学加工、激光加工、电子来加工、水射流加工和快速成形的研究现状，指出特种加工技术的微细化、复合化和自动化等内容是当前的研究热点。     

基于特种加工的微细制造技术

通过例证概括介绍了特种加工方法在微细加工方面所取得的成就，这些加工技术包括：电火花加工、电化学加工、超声加工、激光加工、精密电铸等。阐述了特种加工技术在微细制造方面的特点：擅长加工复杂的三维微机械结构，且投资小，适于中小批量生产。     

国外特种加工技术的最新进展

就当前国际特种加工技术研究的最新进展情况， 从激光加工、电解加工、超声加工尤其是电火花加工等方面进行了较为详尽的阐述。希望能从国外此方面的研究中， 看出２１ 世纪特种加工技术的走向， 并为我国特种加工技术的研究提供借鉴。     

微细电解加工机理探讨

介绍了微细电解加工技术的原理和特点，通过对其加工工艺的分析，简述了在微细电解加工过程中，影响其加工速度、精度、效率的主要因素，并通过对这些因素的综合分析，总结了制约微细电解加工技术应用的因素和进行微细电解加工应具备的基本条件。最后，针对微细电解加工技术的现状，对其发展提出了新的展望。     

书讯

《电火花加工技术》一书介绍了电火花加工的基本原理、电火花成形加工技术、高速走丝电火花线切割加工技术、低速走丝电火花线切割加工技术、其他电火花加工及复合加工技术等内容。《超声加工技术》一书介绍了超声加工的基本原理和特点、超声波发生器、超声换能器、超声材料去除加工、超声表面光整加工、超声焊接加工、超声复合加工等内容。两书内容新颖，注重理论联系实际，     

超声加工概况和未来展望

本文简述了超声加工技术发展、应用特点和应用分类，介绍了超声加工用某些新型超声振动系统及其应用，概述了超声加工某些应用中的基础研究、设备研制和应用研究的情况，指出了超声加工技术的发展前景。     

微磨料空气射流加工技术的发展

微磨料空气射流加工(MAJM)技术是对硬脆材料进行微细加工的一种非常有潜力的技术，特别是对复杂的三维微细结构的加工。微磨料空气射流加工技术是基于传统的喷砂技术发展起来的，通过由空气喷射磨料微粒形成高速气流冲击工件表面而去除工件材料。与其它的加工技术相比，微磨料空气射流加工具有环境友好、易于控制、无热影响区、切口质量好等优点。本文介绍了此技术的基本加工原理、特点以及加工过程中的影响因素，论述了微磨料空气射流加工的材料冲蚀机理和切口特征。重点分析了一些主要的加工参数，例如空气压力、磨料材料、尺寸、供给率、喷嘴的形状和尺寸、喷射距离以及工件材料，对切削性能和切口特征的影响。并提出了微磨料空气射流加工技术中有待进一步深入开展的研究工作。     

绝缘工程陶瓷的特种加工技术

针对用机械磨削方法加工绝缘工程陶瓷存在成本高、效率低和工件表面易产生微裂纹等问题，国内外学者开展了大量的研究工作，并取得了较大的研究进展。概述了绝缘工程陶瓷的激光加工、超声加工、电火花加工、等离子弧切割等特种加工技术，并对这些加工技术的原理、特点和应用状况等进行了分析评述。     

精密特种加工是先进制造技术的重要发展方向

分析了先进制造技术的特点和发展，给出了特种加工概念的扩展和精密特种加工的范畴，介绍了非机械超精密加工技术，最后指出了特种加工技术的发展方向。     

国外电火花线切割加工技术最新进展

结合国外电火花线切割加工技术的最新发展趋势，对新型走丝系统、新型工作液、自动化及人工智能技术、微细电火花线切割加工技术等方面的最新进展进行了详细的阐述，从而提出了电火花线切割加工的发展方向。     

EDM turning using a strip electrode

Turning by electrical discharge machining (EDM turning) is an effective method to machine hard-to-cut materials. Generally, a wire-EDM is utilized in EDM turning because it is not concerned with electrode wear. However, wire-EDM turning has a slow machining speed due to its small machining area, and the wire may break due to overheating electrodes. For these reasons, its machining speed must be limited. In this study, a strip-EDM was created in an effort to overcome the problems in the EDM-turning process. This machining method used a conductive strip as an electrode. The strip was fed continuously, like a wire-EDM; therefore electrode wear was not a concern. One advantage of the strip-EDM was that it increased the material removal rate because of its large machining area and non-breaking electrode. In the experiments, machining characteristics were investigated according to machining conditions, and practical machining was carried out via fabrication of complex shapes on a shaft workpiece.     

Tool life and wear mechanisms in high speed machining of Ti–6Al–4V alloy with PCD tools under various coolant pressures

Usage of titanium alloys has increased since the past 50 years despite difficulties encountered during machining. Many studies involving different tool materials, cutting parameters, tool geometry and cutting fluids when machining this important aerospace material have been published. However, there are relatively few literatures available on the application of ultra hard tools in the machining of titanium-alloys. The primary objective of this study is to investigate the behaviour of Polycrystalline Diamond (PCD) tools when machining Ti–6Al–4V alloy at high speed conditions using high pressure coolant supplies. Tool performance under different tribological conditions and the dominant wear mechanisms were investigated. Increase in coolant pressure tends to improve tool life and reduce the adhesion tendency, accelerated by the susceptibility of titanium alloy to gall during machining. Adhesion and attrition are the dominant wear mechanisms when machining at the cutting conditions investigated.     

Machining performance on hybrid process of abrasive jet machining and electrical discharge machining

To develop a hybrid process of abrasive jet machining (AJM) and electrical discharge machining (EDM),the effects of the hybrid process parameters on machining performance were comprehensively investigated to confirm the benefits of this hybrid process.The appropriate abrasives delivered by high speed gas media were incorporated with an EDM in gas system to construct the hybrid process of AJM and EDM,and then the high speed abrasives could impinge on the machined surface to remove the recast layer caused by EDM process to increase the efficiency of material removal and reduce the surface roughness.In this study,the benefits of the hybrid process were determined as the machining performance of hybrid process was compared with that of the EDM in gas system.The main process parameters were varied to explore their effects on material removal rate,surface roughness and surface integrities.The experimental results show that the hybrid process of AJM and EDM can enhance the machining efficiency and improve the surface quality.Consequently,the developed hybrid process can fit the requirements of modern manufacturing applications.     

Influence of Debris Accumulation on Material Removal and Surface Roughness in Micro Ultrasonic Machining of Silicon

Although micro ultrasonic machining (USM) has been successfully applied in generating micro features in hard and brittle materials such as silicon, the influence of machining parameters on the machining performance is not clearly understood. Experimental results show that the machining speed decreases with an increase in the static load beyond a certain level. In this study, the debris accumulation is proposed as the main reason leading to low machining efficiency. A mathematical model is also developed to analyze this phenomenon qualitatively. Experimental results reveal that the particle size is the dominate factor influencing the surface roughness in micro USM.     

Impact of the shape of electrode-tool on radical overcut of micro-hole in electrochemical micromachining

To make use of the full capability of electrochemical micro-machining (EMM), a meticulous research is needed to improve the material removal, surface quality and accuracy by optimizing various EMM process parameters. Keeping this in view, an indigenous development of an EMM machine set-up has been considered to carry out a systematic research for achieving a satisfactory control on the EMM process parameters to meet the micromachining requirements. In this study an EMM machine has been developed and experiments were conducted to study the influence of some of the major process parameters such as the machining voltage, electrolyte concentrations, the pulse-on-time and the machining current on the machining rate and accuracy. The effect of the shape of the tool electrode tips on EMM has been investigated experimentally with 304 stainless steel sheets. The machining rate and the overcut are significantly influenced by the shape of the tool electrode tip.     

侧铣加工空间刀具半径补偿技术实现

通过对侧铣加工空间刀具半径补偿算法的研究,建立刀具和工件模型,并对其进行了求解和公式推导。对任意侧铣加工曲面进行偏置计算,生成带有刀具半径补偿的侧铣偏置曲面,从而解决了侧铣加工中曲面偏置位置的问题,实现了侧铣加工空间刀具半径补偿,该方法的应用为数控系统研究侧铣空间刀具半径补偿提供了参考。     

Tube electrode high-speed electrochemical discharge drilling using low-conductivity salt solution

Film cooling holes are widely used in the aerospace industry, and their fabrication requires high machining speed and accuracy, as well as good surface quality. Tube electrode high-speed electrochemical discharge drilling (TSECDD) is a promising hybrid machining method for the fabrication of film cooling holes in difficult-to-machine superalloys. An electrochemical reaction can occur if a low-conductivity salt solution is used in the drilling. Materials can also be removed at a high speed using electrical discharge machining (EDM). Thus, TSECDD and electrochemical machining (ECM) can be combined into a unique machining process using a low-conductivity salt solution. This machining process achieves both a high machining speed and good surface finish. In this study, the material removal mechanism of TSECDD was studied using a low-conductivity salt solution, and comparisons with high-speed electrical discharge drilling were made. The performance of the process was investigated using salt solutions of various conductivities. The results show that there are different material removal mechanisms in the frontal gap and the lateral gap and that, in the latter, there is a transition from EDM to ECM. Experiments conducted using TSECDD confirm that the use of this process with a low-conductivity salt solution can improve the machining surface and machining efficiency achieved. The results also show that the use of a low-conductivity solution improves the material removal rate, the hole diameter, and the taper angle.     

飞机铝合金薄壁件的加工质量研究

在薄壁件切削加工过程中的加工变形和良品率低等问题成为了影响零件的加工精度和生产率的主要因素。因此,研究薄壁件加工中变形误差较大和良品率低等问题在理论研究和实际应用中都具有重大意义。对于铝合金薄壁件主要采用实验研究和限元分析相结合的方法,分析数控加工中薄壁件加工质量的主要影响因素,并论述了加工过程中,从加工工艺方案、装夹方案、刀具的选择和走刀路线等方面控制薄壁件的变形、加强加工过程中其刚度的具体改进措施,以提高薄壁件加工效率和质量。     

电解加工机匣型面试验研究

电解加工技术以其自身的特点和优势,被应用于航空发动机机匣型面的加工。该项技术不仅适用于军机制造,对于民机制造也有广泛的应用前景。以某典型航空发动机机匣为例,对机匣电解加工技术进行了研究,其研究结果对机匣类零件的电解加工具有指导意义。     

Machining performance of TiN coatings incorporating indium as a solid lubricant

The machining and wear performance of TiN-coated and patterned carbide inserts incorporating indium as a solid lubricant are reported in this study. Cutting tests were conducted by turning hardened 4340 steel in both lubricated and dry conditions. During turning, periodic flank wear measurements were made. The chips formed during cutting were examined by scanning electron microscopy, as the condition of the chip reflects the conditions obtained during machining. Inserts subject to dry machining were also examined using optical microscopy and X-ray photoelectron spectroscopy to determine the extent of damage on the rake surface as well as the degree of material transfer. The results showed indium to be effective in reducing flank wear during lubricated machining, but little additional benefit of patterning was observed. For dry machining, some degree of improvement was noted in the patterned sample, but the degree of lubricity brought about by the indium coating was not sufficient and the overall flank wear was higher than the lubricated tests. However, the wear and damage on the rake surface along the path of the chip was reduced by the presence of the In-containing microreservoirs. An additional test was conducted using an instrument that simulates temperature effects during machining, and it was found that the lubricity achieved by In coatings is lost above 450 °C. These results suggest that the use of indium is limited to below this temperature, and above this temperature transforms to a less lubricious indium oxide.