单晶硅的磨削辅助电火花线切割机理研究

针对目前磨削辅助电火花线切割(A-WEDM)微观切割机理尚不明确的问题,以单晶硅为加工对象,通过设计电路对最大放电间隙进行了测量。通过采集和分析加工中的放电波形、观测加工后工件表面形貌同时比较磨粒出刃高度与放电间隙的大小,研究了A-WEDM材料去除机理。考察了4个因素(脉冲宽度、占空比、进给速度和线锯速度)对A-WEDM切割单晶硅的材料去除率和表面粗糙度的影响。实验结果表明,A-WEDM切割单晶硅的最大放电间隙为57μm,在加工的初始阶段先产生放电腐蚀作用;当加工处于稳定阶段时,在每个脉冲宽度内,工件材料在放电腐蚀与金刚石颗粒磨削的耦合作用下被去除;而在每个脉冲间隔内,放电腐蚀作用停止,金刚石颗粒的磨削作用仍然存在,从而去除了放电产生的部分重铸层与电蚀坑。     

电火花线切割加工工艺参数研究

电火花线切割加工的表面粗糙度是衡量加工质量的重要指标之一.在加工过程中,表面粗糙度会受到放电电流的影响,其中包括放电电流能量、电流脉冲宽度以及电流极性的影响.通过在快走丝线切割加工机床上进行多次加工实验,本文研究分析了放电电流对线切割加工表面粗糙度的影响规律.     

快走丝线切割脉宽与间隙对加工质量影响分析

通过一系列的实验得出脉冲宽度或脉冲间隔与加工表面粗糙度、精度、机床型号的关系,总结出放电电路能量及电流脉冲宽度、脉冲间隔对线切割电火花精加工表面粗糙度的影响规律.在实际生产加工中,结合实际清况,选择合适的脉冲宽度、脉冲间隔比,调节出合适的加工速度,这样能有效地控制工件的表面粗糙度,提高加工效率.实验结论可为提高线切割加工质量找出一条新途径,也为今后高频电源的开发,加工技术的提高提供重要参考依据.     

GH4169高温合金电火花线切割加工质量预测研究

针对镍-铬-铁基高温合金GH4169电火花线切割加工质量预测问题,通过正交实验设计并结合方差分析,分析放电电流及脉冲宽度、放电间隙、管数、加工限速对GH4169高温合金电火花线切割加工表面粗糙度和线切割速度的影响规律。在实验数据基础上训练BP神经网络,建立脉冲宽度、放电间隙、管数、加工限速对表面粗糙度和线切割速度影响的预测模型,预测结果表明,将正交实验与BP神经网络融合应用在GH4169高温合金电火花线切割加工中,不仅减少了工艺参数优化选择的盲目性,也提高了加工质量的预测精度和效率。     

慢走丝线切割电参数对加工速度影响的正交实验研究

通过正交实验法,研究了慢走丝线切割加工不锈钢时,加工电参数(电流峰值、放电脉宽时间、伺服电压)对加工速度的影响,为合理选用线切割加工电参数提供参考依据。实验表明,峰值电流IP对加工速度影响最明显,放电脉冲宽度ON次之,伺服电压SV对加工速度影响不明显。     

高铌钛铝合金中走丝电火花线切割加工工艺研究

为了研究高铌钛铝合金工件中走丝电火花线切割加工工艺,以脉冲宽度、放电跟踪间隙、运丝速度三个工艺因素为研究对象,基于在中走丝电火花线切割加工高铌钛铝合金工件试验,揭示三个工艺因素对加工效率、切缝宽度扩大量和表面质量的影响。     

一种全闭环中走丝电火花线切割机床数控系统

研究了中走丝电火花线切割机床脉冲放电特性,提出了一种高速数字化采样和间隙跟踪方法,同时建立了智能型放电工艺数据库,提高了切割过程放电效率。为改进切割精度和表面粗糙度,工作台运动采用了一种闭环位置控制方案,基于双平面同步插补法实现了4轴协调运动控制,并采用C补偿原理解决了多次切割控制问题。基于嵌入式操作系统,设计并实现了可视化编程与控制集成软件。实际切割实验数据显示,采用这种数控系统后,中走丝线切割机床的可靠性和加工精度有了显著提高。     

往复走丝电火花线切割高效低损耗切割研究

目前,高速往复走丝电火花线切割最高切割效率已突破200mm2/min,传统脉冲电源靠单纯提高脉冲能量来增加切割效率会导致钼丝损伤大、损耗加剧,短时间内就可能出现断丝。从脉冲电源的放电波形分析入手,分析了传统脉冲电源和高效低损耗脉冲电源的差异。研究认为,采用阶梯脉冲合理控制放电电流的前后沿,在加工中对非正常放电脉冲及时切断以减小对电极丝造成的损伤及损耗,采用等能量脉冲方式提高放电利用率等措施能大大提高切割效率,改善切割表面粗糙度,在切割效率190～200mm2/min条件下能实现长期稳定切割。     

PCD复合片电火花线切割加工丝损分析与研究

采用电火花线切割方法对聚晶金刚石复合片进行了线切割加工实验,利用带能谱分析的扫描电子显微镜((SEM)观察了电极丝表面的显微形貌,进行了元素成分分析。从微观角度研究了PDC超硬材料电火花线切割加工的电极丝损耗机理,探讨了极间脉冲放电、工作液有效进入量、电蚀粒子容积浓度以及电极丝镀覆等因素对丝损的影响。提出采用贴附式高压喷液系统可有效提高切割效率、降低丝损。试验结果表明,该喷液系统能够有效改善极间放电条件,可使切割效率提高51.6%,丝损降低15.2%,为PCD复合片的高效、稳定、低损切割提供了有益参考。     

慢走丝线切割加工参数对表面粗糙度的影响

慢走丝电火花线切割加工精度是衡量加工性能的重要指标之一.在加工过程中,加工表面精度自然受到加工参数的影响,其中包括放电电流能量、电流脉冲宽度等的影响.通过在慢走丝线切割加工机床(日本SODICK机床)上进行多次加工实验观察,分析了不同加工参数对慢走丝线切割加工表面粗糙度的影响规律.     

Optimization of wire electrical discharge machining (WEDM) process parameters using Taguchi method

Wire electrical discharge machining (WEDM) is extensively used in machining of conductive materials when precision is of prime importance. Rough cutting operation in WEDM is treated as a challenging one because improvement of more than one machining performance measures viz. metal removal rate (MRR), surface finish (SF) and cutting width (kerf) are sought to obtain a precision work. Using Taguchi’s parameter design, significant machining parameters affecting the performance measures are identified as discharge current, pulse duration, pulse frequency, wire speed, wire tension, and dielectric flow. It has been observed that a combination of factors for optimization of each performance measure is different. In this study, the relationship between control factors and responses like MRR, SF and kerf are established by means of nonlinear regression analysis, resulting in a valid mathematical model. Finally, genetic algorithm, a popular evolutionary approach, is employed to optimize the wire electrical discharge machining process with multiple objectives. The study demonstrates that the WEDM process parameters can be adjusted to achieve better metal removal rate, surface finish and cutting width simultaneously.     

An experimental study on micro wire-EDM of polycrystalline diamond using a novel pulse generator

This paper presents a new pulse generator for cutting of polycrystalline diamond (PCD) by micro wire electrical discharge machining (micro wire-EDM). The pulse generator using anti-electrolysis circuitry and digital signal processor-based pulse control circuit was developed to suppress damages on the machined surface of PCD while achieving stable machining. A novel pulse control method was proposed to provide high-frequency pulse control signals with a period of off duty cycle for reionization of the dielectric in the spark gap so as to reduce the consecutive occurrence of short circuits. A series of experiments were carried out to investigate the effect of open voltage on machining performance in terms of material removal rate, slit width, thickness of the damaged layer on machined surface, and surface finish. An increase of open voltage increases peak current, thus producing greater discharge energy and, thereby, contributing to improvements in material removal rate, but leading to larger slit width and thickness of the damaged layer and worse surface finish. Experimental results not only demonstrate that the developed pulse generator could achieve satisfactory machining results but also have verified the applicability of this new technique in micro wire-EDM.     

Parametric optimization for surface roughness, kerf and MRR in wire electrical discharge machining (WEDM) using Taguchi design of experiment

This paper reports the effect and optimization of eight control factors on material removal rate (MRR), surface roughness and kerf in wire electrical discharge machining (WEDM) process for tool steel D2. The experimentation is performed under different cutting conditions of wire feed velocity, dielectric pressure, pulse on-time, pulse off-time, open voltage, wire tension and servo voltage by varying the material thickness. Taguchi’s L18 orthogonal array is employed for experimental design. Analysis of variance (ANOVA) and signal-tonoise (S/N) ratio are used as statistical analyses to identify the significant control factors and to achieve optimum levels respectively. Additionally, linear regression and additive models are developed for surface roughness, kerf and material removal rate (MRR). Results of the confirmatory experiments are found to be in good agreement with those predicted. It has been found that pulse on-time is the most significant factor affecting the surface roughness, kerf and material removal rate.     

Experimental investigation and prediction of optimum process parameters of micro-wire-cut EDM of 2205 DSS

Micro-wire-cut electrode discharge machining (EDM) is an emerging manufacturing process in the field of micro-manufacturing to fabricate the complex profiles of micro-components. It is a complex process involving various process parameters such as pulse on time, pulse off time, wire speed, wire tension and current. In addition to micro-fabrication, this process can also be extended in the field of tool design and developments such as dies, moulds, precision manufacturing, contour cutting, etc., where complex shapes need to be generated with high-grade dimensional accuracy and surface finish. In this research work, an attempt is made to investigate the effect of process parameters on the output variables such as material removal rate (MRR), surface finish and the cutting width (kerf) of wire-cut EDM for duplex stainless steel (DSS). Scanning electron microscopy (SEM) has been used to capture the images of the kerf width, and the measurements are taken with the help of the welding expert system and software. An optimization technique (Taguchi method) has been employed to identify the optimum parameters of the micro-wire-cut EDM process for cutting 2205 grade duplex stainless steel. The effect of each control parameter on the performance measure is studied individually using the plots of signal to noise ratio.     

基于脉冲电源的金属电化学线切割工艺研究

为了提高金属电化学线切割精度,将脉冲电源应用到切割加工中,根据电化学加工原理,并以切割缝宽为切割效果的评价标准,建立了脉冲电源切割理论模型,得出了影响缝宽变化的工艺参数,主要有:电源的电压幅值、脉冲宽度、占空比和进给速度等。并在此基础上对参数进行了优化加工实验。研究结果表明,在保证加工稳定的条件下,通过降低电压、调小脉冲宽度和占空比的方法,加工出的切割缝宽比直流电源加工出的缝宽明显减小,该方法将有望直接用于小尺寸零件的加工。     

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。     

聚晶金刚石复合片电火花线切割加工电极丝损耗研究

采用电火花线切割方法对聚晶金刚石复合片（PDC）进行了线切割加工实验,利用带能谱分析的扫描电子显微镜(SEM)观察了电极丝表面的显微形貌。从微观角度研究了PDC超硬材料电火花线切割加工的电极丝损耗机理,探讨了电参数和冲液条件等因素对电极丝损耗的影响。实验研究发现,采用贴附式高压喷液方式在高电压、小脉宽、大峰值电流的加工条件下,PDC切割效率为19.35mm2/min,电极丝损耗为1.5~2μm(104mm2切割量),较常压喷液方式切割效率提高51.6%,丝损降低15.2%。     

Application of Taguchi,ANFIS and grey relational analysis for studying,modeling and optimization of wire EDM process while using gaseous media

In the dry wire electrical discharge machining (WEDM) process, the liquid dielectric is replaced with gaseous medium to enhance the machining environment safety. Also, this modification improves the surface quality of machined specimen but decreases the material removal rate of the process. In the present work, experimental study of dry WEDM process has been performed while machining of Al/SiC metal matrix composite. At first, a series of exploratory experiments has been conducted to identify appropriate gas and wire material based on their cutting velocity. After selection of the best gas and best wire, they were used for later stage of experiments. At the next stage, experiment were designed and conducted based on L₂₇ Taguchi's orthogonal array to study the effect of pulse on time, pulse off time, gap voltage, discharge current, wire tension and wire feed on cutting velocity (CV) and surface roughness (SR). Analysis of variances (ANOVA) has been performed to identify significant factors. In order to correlate relationship between process inputs and responses, adaptive neuro-fuzzy inference system has been utilized. At the end, a grey relational analysis has been used to maximize CV and minimize SR simultaneously. Results indicated that oxygen gas and brass wire guarantee superior cutting velocity. Also according to ANOVA, pulse on time and current were found to have significant effect on CV and SR.     

基于C8051单片机的电火花线切割自适应电源研究

对电火花线切割脉冲电源的原理进行了探讨与分析,介绍了一种基于C8051单片机的新型电火花线切割自适应电源的设计方法.对放电状态进行在线检测,该系统能够通过对放电脉冲的自适应调整,使极间放电状态总是处于理想状态,能够较好地适应加工条件的剧烈变化,大大提高了线切割加工过程的稳定性和加工品质.