提高线切割加工精度的方法

电火花切割是一种直线电极的展成加工方法,因为它使模具(尤其是复杂模具)加工工序简化、生产周期缩短而倍受人们欢迎,被广泛地应用于模具制造行业。但由于我国快走丝线切割机床的结构设计、制造精度以及加工工艺指标等方面和国外同类机床相比还有差距,所以在加工精度要求较高的模具时,我国的一般线切割机床不能满足精密加工     

复合运丝型电火花线切割加工参数分析与研究

提出了一种新型电火花线切割机床,即电极丝作往复直线运动的同时还绕自身轴线高速旋转的复合运丝型线切割机床。介绍了该类机床与其他线切割机床加工的基本工艺指标。通过与高速走丝电火花线切割机床比较实验,分析了脉冲宽度、脉冲间隔、脉冲峰值电流等电参数对加工工艺指标的影响,实验表明这种独特的复合运丝方式在降低表面粗糙度、提高加工精度等方面较传统运丝方式具有较大的优越性,且机床结构较为简单,对于各种工艺参数和电参数具有更加广泛的适用性,具有进一步研究和推广价值。     

快走丝切电火花线割机床割铝装置的设计

快走丝电火花线切割机床切割铝件时出现导电块磨损严重、电极丝与导电块之间有电火花产生、断丝现象频繁等不良现象,严重影响了铝件的表面加工质量和加工效率。首先分析了线切割机床切割铝件时产生上述不良现象的原因;然后通过改变原有的导电块导入脉冲电源负极的方式,采用储丝筒导入脉冲电源负极的方式,并设计了专用的脉冲电源负极导入装置,确保电极丝与电源的可靠接触;最后通过实验验证了设计方案的可靠性和正确性,为铝件的切割加工提供了技术支持。     

第十二届中国国际机床展览会特种加工机床评述（下）

二、电火花线切割机床（WIRE-CUT）1.国外单向走丝电火花线切割机床国外单向走丝电火花线切割机床的技术发展水平,着重针对电火花线切割加工特点及应用情况,在脉冲电源、自动控制及主机结构等影响线切割加工三大指标的几个关键功能部件上有所创新,并且在实用性、稳定性、可靠性,以及各功能模块的自适应控制性能等方面有所提升（1）脉冲电源技术高效电火花脉冲电源是单向走丝线切割机床的核心单元,高频脉冲电源的自适应控制策略的优劣,对单向走丝线切割的加工效率、加工精度,     

电火花线切割加工工艺特点分析

线切割加工是电火花线切割加工的简称,它是用线状电极(钼丝或钨丝)靠电火花放电来对工件进行切割。线切割机床通常分为两类:快走丝和慢走丝。前者     

往复走丝线切割电极丝精确定位方法及系统开发

电火花线切割加工精度取决于其定位精度和定形精度,而定位精度主要取决于线切割中电极丝的定位精度。分析影响电极丝位置精度的因素:丝杠等机械系统的传动精度、电极丝与工件的位置精度和电极丝的垂直度等。提出了"矩阵化"补偿方法和智能接触感知方法,开发了精确移轴、碰边、对中和校垂直等定位模块。该方法应用于往复走丝线切割数控系统,提高了电火花线切割加工的精度。     

模具线切割精密加工电极丝的应用分析

模具数控线切割加工电极丝的定位是加工程序的起始位置,整个切割图形相对于模具件的位置正确性完全取决于电极丝的严格定位。CTW机床的走丝机构采用十字滑板,U、V轴移动并具有独特的四连杆技术实现锥度加工。通过电极丝位置调整方法、电极丝的选择、线切割加工前的工艺准备及常见断丝、抖丝故障的介绍,目的是为了更好地使用快走丝电火花线切割机床来加工复杂模具精密零件。     

可逆单向走丝线切割机床双丝筒走丝系统的设计

提出了可逆单向走丝线切割机床的概念,阐述了可逆单向走丝线切割机床的技术方案,设计了超长电极丝双丝筒结构多层绕丝的走丝系统,探讨了可逆单向走丝线切割机床走丝系统的控制要求及控制系统的实现方案。本方案设计的走丝系统既可以实现单向走丝机床的无条纹高精度加工要求,又可以实现电极丝重复使用的往复走丝机床低运行成本要求,还可以实现大厚度零件的切割加工,为往复走丝机床实现高精度加工提供了一个有效的平台,是未来往复走丝机床走丝系统的一个发展方向。     

电极丝及丝速和条纹对线切割的影响

文中在叙述线切割机床的电极丝种类、特性及直径的基础上，分析了走丝速度、电极丝往复运动引起的条纹对加工速度和表面粗糙度的影响。     

加工斜度时线切割刀位点的修正

线切割加工廓形精度要求较高的斜度刀具时 ,应采用偏摆钼丝法 ,并对走丝轨迹进行修正。介绍刀位点的修正方法并导出了相关公式 ,给出在线切割CAD/CAM软件中实现修正的步骤。     

电火花线切割加工断丝原因分析

高速电火花线切割加工中经常会发生断丝现象,断丝不仅会因为穿丝而降低加工效率,还会因为重复切割导致加工精度下降。文中从断丝的根本原因入手,全面分析了加工中各种因素对断丝的影响,指出影响断丝的主要因素是电极丝的直径、电极丝的磨损、电极丝的张紧力、工作液的介电性能和化学性能、机床的导丝结构以及加工参数。     

线切割加工中断丝原因分析与排除办法

在线切割加工中,断丝是最常见的一种情况,倘若掌握好加工方法与技巧,断丝是可以避免或大大减少的。本文以线切割加工中的高速走丝和低速走丝2种机床为例,分别从加工前、加工后和加工中3方面分析了断丝的原因,并提出了有效的解决办法,提高了线切割加工的效率。     

Investigating and removing the re-sticky debris on tungsten carbide in electrical discharge machining

Electrical discharge machining (EDM) is an excellent method to machine tungsten carbide with high hardness and high toughness. However, debris from this material produced by EDM re-sticking on the workpiece surface remarkably affects working efficiency and dimension precision. Therefore, this study investigated the re-sticky phenomenon of tungsten carbide and how to reduce the debris re-sticking on the workpiece surface. In general, the polarity in EDM depended on the different electrical parameters of the machine input and the different materials of the tool electrode. The first item of investigation observed the re-sticky position of the debris to study the effect of different polarities during the EDM process. Next, the tool electrode was set at different conditions without rotation and with a 200 rpm rotational speed to evaluate the rotating effect in EDM. Finally, different lift distances of the electrode and different shapes of electrode with rotation were utilized to investigate the improvement for reducing debris re-sticking on the machining surface. The results showed that only negative polarity in EDM could cause the re-sticky phenomenon on tungsten carbide. On the other hand, debris would notably re-stick on any machining position when the tool electrode was not rotated in EDM. Besides, debris significantly stuck on the center of the working area with rotation of the electrode. Additionally, a larger lift distance of the tool electrode could reduce debris re-sticking on the working surface, but this process would decrease material removal rate in EDM. In the end, a special shaped design of the tool electrode resulted in the re-sticky debris completely vanishing, when the electrode width was 0.6 times the diameter of this cylindrical electrode.     

电火花线切割高速走丝机床常见故障与排除

电火花线切割加工过程是电化学、热力学和流体动力学等多方面知识的综合应用,因此,诱发电火花线切割加工机床出现故障的原因也较多。结合生产实际对电火花线切割机床的常见故障进行了分析,并给出了相对应的排除方法。     

Super-high-thickness high-speed wire electrical discharge machining

High-speed wire electrical discharge machining (WEDM-HS) of materials of super-high thickness (more than 1000 mm) is a challenging problem. First, sufficient energy is required to maintain the inter-electrode normal discharge. Next, there must be adequate inter-electrode dielectric fluid. Third, in order to generate a smooth cut surface, it is necessary to suppress the vibration of the wire electrode to reduce vibration lines on the cutting surface. To better understand these challenges, the energy and the flow of the medium between two electrodes were analyzed, allowing the establishment of a relevant model. The results indicated that for super-high-thickness machining, the pulse energy must be adequate to compensate for the energy consumed in the molybdenum wire and inter-electrode working liquid. In addition, the running speed of the wire electrode should be improved to ensure that there is a sufficiently high flow rate of the dielectric fluid. The servo control mode of the existing machine tools and dielectric fluid were improved and then a process experiment was performed. The experimental results show that the process can be carried out efficiently and stably and the workpiece surface can be cut smoothly using the improved working liquid and servo control mode.     

窄缝精密电解加工的实验研究

通过在理论上分析窄缝电解加工中片状电极和丝状电极对加工间隙和流场分布的影响,提出了采用小直径丝状电极提高加工精度和改善加工稳定性的方法。文中分别进行了片状电极和丝状电极之间、不同直径丝状电极之间的窄缝电解加工对比试验。结果表明,小直径丝状电极可以减小电解液流过电极丝产生的涡流死水区,改善加工区内的电解液更新和电解产物的排除,提高加工精度和加工过程的稳定性。     

Fabricating microgrooves with varied cross-sections by electrodischarge machining

A two-step electrodischarge machining method was proposed for fabricating microgrooves with varied cross-sections on hard materials. Firstly, tungsten tool electrodes were shaped by wire electrodischarge grinding, and then the resulting tool electrodes were used to electrodischarge machine microgrooves on stainless steel. Preliminary experimental results showed that, in the first step, a sharp tool electrode with surface roughness of 0.3 µmRa could be achieved, and the surface roughness of the resulting groove was 0.16 µmRa in the second step. Voltage strongly affects the machining speed. A high voltage (>70 V) was preferable for improving the material removal rate. However, significant tool wear took place when using a high condenser capacitance at high voltages. To suppress tool wear, a high voltage and a small capacitance should be used. As test pieces, microgrooves having rectangular, triangular, circular and semi-closed cross-sections were fabricated.     

Approaches for improvement of EDM cutting performance of SiC with foil electrode

Electrical discharge machining by foil electrode serves as an alternative method for SiC slicing. This technology uses a highly tensioned thin foil as the tool electrode. The main advantages over wire EDM are that the foil thickness can be made smaller than the wire diameter, vibrations can be avoided by applying high tension, and higher current can be supplied since there is less risk of tool breakage. However, due to the large side surface area of the foil electrode, there is a high occurrence probability of side surface discharges and high concentration of debris, which affects kerf width accuracy and machining stability. In the aim to overcome both problems, this study proposes two foil electrode designs: a foil electrode in which holes are machined and the insulation of the side surface areas by a resin coating layer of 5 μm thickness. The influences of both foil electrodes were tested with three different slicing strategies: no strategy, applying jump motion of the tool electrode, and applying reciprocating motion. From machining experiments and comparative studies of the discharge delay time, it was found that with both foil tools, the occurrence probability of side surface discharges can be reduced. In addition, the chip pocketing effect of the holes enhance the flushing conditions, resulting in a higher cutting speed.     

PCD成型刀具单向走丝线切割加工工艺

从PCD刀具材料、主要放电参数选择、切割工艺及放电铜丝等方面研究影响单向走丝线切割PCD刀具的相关因素,从而选择合适的刀具刃口光洁度、轮廓精度、加工效率和圆跳动量。