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用实验的方法研究电火花微细加工中放电能量在极间的分配和对电极损耗的影响,并研究式具电极材料和工件材料对电极损耗的影响,实验表明,从减小电极损耗,增加有用功率出发,电火花微细加工应使用微能窄脉冲电源。 相似文献
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电火花腐蚀的微观过程是电磁力、热动力以及流体动力等综合作用的过程。电火花加工中电流在电极和工件中流动时存在趋肤效应,流经电极端面和工件表面的电流在放电通道还会产生电磁场,同时放电时两极间电压在放电通道形成电场;因此运动粒子在通道中运动会在电场和磁场作用下发生改变,进而影响最终电加工特性。通过理论分析并进行相应的计算确定放电时通道内的电磁场,来分析该电磁场对形成放电通道的等离子体运动轨迹的影响,进而来研究放电加工时放电通道内的电磁场对加工机理的影响,并通过实验验证计算模型,实验结果和计算模型非常接近。 相似文献
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电火花成形加工主要基于脉冲放电时的电火花腐蚀原理:当工具电极与工件在绝缘液体介质中相互靠近时,极间脉冲电压将两极间"相对最近点"的液体介质电离击穿,形成脉冲放电,并在放电通道中瞬间生产大量的热能,使局部金属融化甚至气化,而将金属蚀除下来。 相似文献
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多孔质电极电火花加工采用多孔材料作为工具电极。多孔质电极由紫铜颗粒经高温烧结获得,在加工过程中可利用颗粒间孔隙形成的流道实现分布式的全向内冲液。通过制备符合电火花加工要求的多孔质电极并搭建实验系统,对多孔质电极的电火花加工性能进行了实验研究。经与实体电极进行对比发现,在工件上表面加工较浅的型腔时,由于多孔质电极表面不平整,易发生大量的侧向放电,其在材料去除率方面与实体电极相比没有优势;而在深孔中加工时,由于排屑条件恶化,采用多孔质电极后可利用分布式的内冲液极大改善极间状态,并可采用不抬刀方式加工,相同条件下材料去除率达到实体电极的4倍。 相似文献
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提出一种新加工方法——放电诱导可控烧蚀及电火花修整成形加工(简称间歇烧蚀加工)。利用极间金属材料在高压氧气间歇通入阶段产生剧烈烧蚀并将蚀除产物吹离加工区域这一特性来实现材料的高效蚀除及较低电极相对损耗率的目的,且在氧气关闭阶段进行常规电火花加工以对表面进行修整,保证了加工表面精度及质量。与火花油、水中传统加工和持续烧蚀加工的试验对比表明:在相同电参数下,间歇烧蚀加工的材料去除率较传统火花油中的电火花加工提高了4.28倍,相对电极损耗率降低了72%。通过放电波形分析了间歇烧蚀的加工机理,并基于电极对的表面微观形貌和成分分析对其加工特点进行了研究。 相似文献
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针对电火花放电间隙状态变化特性的检测与分析等问题,利用凌华PCI-9846四通道高速数字化仪建立了测量系统,讨论了电火花加工放电间隙放电特性测量方案,测量了不同加工状态下放电间隙两端的电压波形和电流波形,分析了空载、正常火花放电、过渡电弧放电和短路等不同加工状态下的电压波形特征及其特征参数。研究结果表明,正常火花放电、过渡电弧放电和短路等不同加工状态下间隙电压的阈值范围不同,且与加工电流有关;在设计伺服控制器时,应根据电源电压、加工电流、工件材料等来动态修正电压阈值。 相似文献
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Study on the characteristics of plasma channel based on multi-spark pulse discharge machining effect
Yang Shen Jilun Chen Yiming Yang Kun Zhang Yong Li Bo Zhu 《The International Journal of Advanced Manufacturing Technology》2018,97(5-8):1745-1752
Plasma channel characteristics and energy distribution in electrical discharge machining (EDM) were mostly studied by analyzing the geometry parameters of craters caused by a single pulse discharge in previous studies. However, single pulse experiments cannot provide us insights into superposition, migration, abruption, interruption, and other phenomena of the plasma channel which have significant effects on EDM. Besides, EDM itself is a consecutive pulse discharge process. Thus, this paper focuses on the characteristics of plasma channel and the mechanism of material removal based on experimental data from multi-spark pulse discharge machining. The contrastive milling experiments of different parameters in multi-spark pulse discharge machining in high-speed dry EDM by using nickel-based superalloy as workpiece were conducted. The effects of peak current, dielectric type, breakdown voltage, air pressure, and electrode rotation speed on the crater number, crater distance, crater depth, and crater removal volume were studied. The plasma channel characteristics and material removal mechanism in continuous machining of high-speed dry EDM were revealed. 相似文献
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采用紫铜工具电极,在峰值电流为4-24A、脉冲宽度为25-200μs、加工电压为80-200V的电参数范围内,综合应用因子试验和正交试验方法,对难加工材料4Cr5MoVSi进行了电火花加工试验。在进行电加工基础特征规律分析的基础上,考查了电参数对加工速度、双边侧面放电间隙、电极损耗的影响,并对电火花加工机理进行了分析。研究结果表明:采用紫铜电极电火花加工4Cr5MoVSi,在本试验范围内,峰值电流Ip与脉冲宽度ti、加工电压U、脉冲间隔t0存在一定的交互作用;与其它三个因素相比,峰值电流对加工速度、电极损耗、双边侧面放电间隙的影响更显著;随脉冲宽度和加工电压的增大,电极损耗逐渐减小。 相似文献
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Joško Valentinčič Bogdan Filipič Mihael Junkar 《The International Journal of Advanced Manufacturing Technology》2009,41(9-10):865-870
In electrical discharge machining (EDM), appropriate average current in the gap has to be selected for the given machining surface in order to obtain the highest material removal rate at low electrode wear. Thus, rough machining parameters have to be selected according to the machining surface. In the case of sculptured features, the machining surface varies with the depth of machining. Hence, the machining parameters have to be selected on-line to obtain appropriate current density in the gap. In this paper, inductive machine learning is used to derive a model based on the voltage and current in the gap. The sufficient inputs to the model are only two discharge attributes extracted from the voltage signal in the gap. The model successfully selects between two machining parameter settings that obtain different average surface current in the gap. It requires only voltage signal acquisition during the machining process and a simple algorithm that is easy to implement on industrial machines. 相似文献
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为提升电火花加工TC4钛合金的表面加工质量和加工效率,选取紫铜圆柱电极开展TC4钛合金电火花小孔加工试验,采用正交试验法,以电极相对损耗率、表面粗糙度、工件材料去除体积为工艺指标,分析峰值电流、维持电压、放电脉宽对工艺指标的影响重要性。采用RBF(Radial basis function)神经网络对已有试验数据进行训练,建立放电参数与工艺指标之间的数学预测模型。以该预测模型为适应度函数,将遗传算法与Skyline选择算法结合进行多目标优化仿真,得到最佳工艺指标,最后开展多目标优化验证试验。结果表明:当峰值电流为14 A、维持电压39 V/42 V、放电脉宽102μs/108μs时能够取得最优的加工结果,优化值与试验值误差较小。 相似文献
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F.-T. Weng M.-G. Her 《The International Journal of Advanced Manufacturing Technology》2002,19(4):266-270
The micro machining of copper plates by the electrical discharge machining (EDM) process is described. Tungsten carbide was
selected as the material for the electrode. Experiments were carried out on a conventional CNC-EDM machine to investigate
machining of micro holes, and micro slots. The results show that micro holes, and micro slots can be successfully processed
on a conventional CNC-EDM machine. To improve the productivity of micro parts using the EDM process, a batch production method
of micro EDM using multi-electrodes has been studied. A new technique for preparing multi-electrodes has been developed. Results
also show that the batch production of micro parts using EDM is feasible and that the batch production of micro parts using
EDM process with multi-electrodes is very effective. 相似文献
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Today the use of high-strength carbon fiber-reinforced plastics (CFRP) composite as a material for many engineering applications is showing an increasing demand in the industry. These composites are replacing the traditional use of steel because they offer many advantages such as very light weight, high strength, and high stiffness associated with good corrosion-resistant properties. Unfortunately, there is little technological knowledge on the electrical discharge machining (EDM) process of high-strength composite materials, especially about the CFRP. In this work, a study has made into the possibility of using EDM process as a means of machining CFRP composite. Various cutting conditions such as peak current, pulse-on time, pulse-off time and open-circuit voltage were selected to perform electrical discharge machining. The effect of electrode rotation was also studied. Optimum cutting conditions and machine settings for EDM were chosen for machining CFRP composites. 相似文献
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为了实现电火花加工同一时刻形成多个放电通道蚀除工件,克服现有放电加工理论中同一时刻仅有一个放电通道蚀除工件的限制,提出了采用半导体材料作为电极进行放电加工的新方法。首先,通过试验证明以半导体硅为电极加工金属可以形成多通道放电;其次,建立了半导体电极单通道放电等效电路模型,发现半导体电极在放电加工时不是一个等势体,并进行了电势差分布试验,验证了多通道放电形成的原因是远离放电点处的电势较高,可以同时形成击穿产生放电;最后,进行了半导体硅电极单脉冲放电试验及成型加工试验。试验结果显示,半导体硅电极通过1次脉冲放电同时形成多个放电通道,有效地分散放电能量,相较于金属电极,每个放电坑的直径和深度都显著减小。在相同放电参数下,对比钢电极,用硅电极进行电火花加工的表面粗糙度值下降71.7%。 相似文献
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Byung Han Yoo Byung-Kwon Min Sang Jo Lee 《International Journal of Precision Engineering and Manufacturing》2010,11(4):629-632
Electrical discharge machining (EDM) is a process that can be used effectively to machine conductive metals regardless of
their hardness. In the EDM process, material removal occurs because of the thermal energy of the plasma channel between the
electrode and the workpiece. During EDM, the electrode as well as the workpiece is abraded by the thermal energy. Tool wear
adversely affects the machining accuracy and increases tooling costs. Many previous studies have focused on mitigating the
problems of tool wear by investigating various EDM parameters. In this study, the tool wear problem was investigated on the
basis of the mobilities of electrons and ions in the plasma channel. The material removal volumes of both the electrode and
the workpiece were compared as functions of the gap voltage. The material removal difference according to the capacitance
was also investigated. The tool wear ratio was calculated under different EDM condition and an EDM conditions for reducing
the tool wear ratio was suggested. 相似文献
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气体放电加工基础工艺试验研究 总被引:1,自引:2,他引:1
采用单因素法进行了基本的工艺参数(电参数、伺服参考电压等)对气体介质放电加工性能影响的试验研究。试验结果表明:气体介质的放电加工适于采用正极性加工。在试验加工的范围内,工件的蚀除速度和表面粗糙度值随脉冲宽度和峰值电流的增加而增加,随脉冲间隔的增加而减小。极间并联合适的电容能够使加工速度和加工表面粗糙度有所改善,并对此现象进行了分析。对于某一确定的加工参数,存在一个较佳的伺服参考电压值,使加工性能较为稳定。工具电极具有较高的旋转速度能够使气体放电加工性能得到提高。使用氧气介质能够实现快速电火花加工,并根据不同气体的物理性能对不同气体介质的加工性能进行了分析。工件表面显微硬度测试结果表明:空气中放电加工的工件的表面硬度比基体硬度高,比煤油中加工的工件表面硬度低。 相似文献