气中高速走丝电火花线切割放电状态的研究

气中电火花线切割加工是电火花线切割精加工的发展趋势.因此对气中电火花放电状态的检测是电火花线切割加工过程中极为重要的一个环节,文中介绍了利用放电状态时不同的电压波形对放电状态进行区分并分析了它们的特点.     

慢走丝线切割放电状态在线识别新方法

在慢走丝电火花线切割加工过程中,由于其放电机理的复杂性、放电点的随机性和最优加工参数的不确定性,放电加工过程中的放电间隙电压可大致分为开路、正常放电、电弧、短路和复杂放电五种放电波形。在不同加工参数下,各类放电波形的比例不一样,不适当的加工参数将显著降低正常放电波形的比例,严重影响慢走丝加工过程中的效率、精度和稳定性。建立一种慢走丝线切割放电状态浮动电压阈值在线识别方法,在放电波形识别系统中,根据不同的加工工况,调节阈值电压的参考值。再根据识别的各种放电波形的比例,采取相应的措施,改变加工参数,已达到最优的放电波形比例。实验数据表明,该系统具有较高的识别精度、实时性和稳定性,且提高材料去除率约20%,降低表明粗糙度约27%,该放电波形识别系统可在电火花线切割加工中具有较好的实用性。     

电火花线切割加工中放电间隙大小在线识别

为实现对线切割加工中放电间隙大小的在线识别，开发了电火花线切割加工间隙放电状态检测系统。在试验的基础上，运用时序分析法研究了放电间隙大小与间隙放电状态之间的关系；构造了一个反映放电间隙大小的样本空间，并以此训练一个神经网络模型来在线识别放电间隙大小。试验表明，该模型能较好地识别放电间隙大小。     

基于统计分析的电火花线切割加工稳定性研究

研制了电火花线切割加工间隙放电状态检测系统,并运用时序分析理论中的统计检验的方法对加工中由正常放电相对时间比率值构成的时间序列进行了分析,指出了电火花线切割加工稳定时的正常放电相对时间比率值构成的时间序列的统计特征。提出用量纲一波形参数——峰度值（峭度系数）来判断电火花线切割加工的稳定性,用试验的方法研究了该方法的可靠性,为采取适当的电参数控制策略,提高加工稳定性提供了重要的依据。     

基于极间阻抗特性的微细电火花放电状态检测系统设计

微细电火花放电状态的检测和放电间隙的准确控制是保证高质量、高效率加工的重要基础。基于极间阻抗变化特性,提出了新的检测方法,利用ADS8681和STM32设计了微细电火花放电状态检测系统。利用串口与电源控制模块通信,实现检测使能控制和检测状态反馈;极间电压信号通过SPI控制ADS8681采集,作为状态判断依据;DAC输出模块负责输出控制信号。经测试该系统能准确识别极间放电状态,并根据加工控制策略输出差分控制信号。     

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.     

基于虚拟仪器的电火花线切割放电状态检测系统

分析了高速走丝电火花线切割机床放电状态特性,在实验研究的基础上,对各种放电脉冲状态进行了检测与判别。以Labview为软件开发平台,设计了快走丝电火花线切割放电状态实时检测控制系统。该系统可通过数据采集卡对放电电压进行实时采集,并由开发的软件平台对采集的信号进行分析与处理,同时还可将采集的数据存盘。实验结果表明,该系统具有界面友好、易于操作等特点,所设计的系统方案合理可行。     

浅析电参数对快走丝电火花线切割表面质量和加工精度的影响

针对快走丝电火花线切割中存在的表面质量差、加工精度低的问题,分析了快走丝电火花线切割加工条件中放电参数（脉冲宽度ON、功率管数IP、脉冲间隔OFF、开路电压、脉冲频率）对零件表面粗糙度、加工精度的影响,为快走丝电火花线切割加工积累了经验。     

基于光信号的电火花线切割数据采集系统研究

针对电火花加工过程中利用电压、电流波形等电信号对放电间隙状态监测存在的易受干扰等不足,提出了一种基于放电火花光信号图像的信息采集方法与控制系统.该系统包含机床硬件与控制、数据采集及上位机控制程序等模块.以STM32开发板为控制内核,通过RS232与上位机通讯,实现机床电器控制;以Hispec高速摄像机与NI6366数据采集卡为时钟同步采集装置,分别通过TCP/IP协议及USB总线与上位机通讯,实现电火花放电图像和放电间隙电压和电流信号的同步采集;在此基础上,以PC机为上位机,运用LabVIEW软件,设计了采集界面及控制程序,实现机床的实时控制、采集数据的保存、回放及分析处理等功能.实验分析结果表明,通过分析处理空载脉冲、正常脉冲及非正常脉冲等不同放电状态下的采集数据,可有效识别放电间隙状态,为利用火花图像特征建立放电状态的预测模型提供了一种新思路,从而为高效的多槽电火花线切割中的解耦控制问题提出解决方案.     

工程陶瓷材料电火花线切割加工的机理研究

针对如何提高工程陶瓷材料加工质量这一问题,对碳化硼工程陶瓷进行了电火花线切割加工的试验研究.介绍了工程陶瓷材料的电火花放电加工原理,通过对碳化硼工程陶瓷进行的电火花线切割加工工艺试验,探讨了电参数对工程陶瓷电火花线切割加工表面质量的影响规律.该研究对进一步深化电火花加工技术的基础理论,促进该技术在实际生产中的推广应用具有重要意义.     

A Study on an Open Architecture CNC System with a NURBS Interpolator for WEDM

This paper deals with the design and implementation of an open architecture CNC system for wire electrical discharge machining (WEDM) with a consideration of the differences between WEDM and NC cutting machines. Work using open architecture controllers (OACs) has focused mainly on metal cutting machines. WEDM has many aspects similar to milling machines. However, there are differences in the machining processes and control strategies. To close the gap between previous general work on OAC and the WEDM specific needs, an open architecture NC model for WEDM comprised of a synchronisation kernel and an NC functional module is proposed. The proposed CNC system is applied to an existing commercial WEDM system by a retrofitting method. A precise NURBS interpolation function is implemented and sample runs are conducted with a NURBS interpolator that is added to the proposed system.     

Study on the Variations of Form and Position of the Wire Electrode in WEDM-HS

The electrode, a tool which is used for wire electrical discharge machining (WEDM), is a tiny flexible metal wire, therefore, in WEDM machining process, its form and position will inevitably vary because of the action of many forces, and these dynamic variations have a direct influence on machining precision and stability, especially in the high-speed WEDM (WEDM-HS) machine process; the variations of form and position have been a critical obstacle to improving machining quality and implementing multi-cut processing. In this paper, the variation regularity of wire-electrode has been investigated by experimental analysis, and some corresponding measures have been suggested to stabilize the form and position of the wire electrode in the WEDM-HS machining process.     

探讨高速走丝电火花线切割加工断丝故障分析及预防

高速走丝电火花线切割加工能够满足我国模具制造以及机械加工的需要,但是在高速走丝电火花线切割加工的过程中容易出现断丝的情况,这对于快速的机械加工以及模具制造而言有着非常大的影响。详述高速走丝电火花线切割加工的原理、高速走丝电火花线切割加工断丝的故障原因以及高速走丝电火花切割加工中断丝故障的解决方法及预防。对于高速走丝电火花线切割加工中断丝的情况要进行分析并预防。     

基于PWM技术节能型线切割脉冲电源的研制

分析了线切割脉冲电源电能的利用现状，简要介绍了目前节能型电火花脉冲电源的研究情况。研制了一种新型的节能型线切割加工脉冲电源。并对其原理进行了探讨。     

金刚石铣刀线切割加工参数优化系统

开发了金刚石铣刀线切割工艺参数优化系统,该系统由优势因素分析模块、工艺参数优化模块和刃磨效果预测模块组成,可实现金刚石铣刀线切割磨削加工参数的优化选择和刃磨效果预测。     

Improvement of wire electrical discharge machining efficiency in machining polycrystalline silicon with auxiliary-pulse voltage supply

This study proposes a novel pulse voltage configuration, auxiliary-pulse voltage, for wire electrical discharge machining (WEDM) of polycrystalline silicon (polysilicon) used in solar cell production. It is developed with the objectives of reducing material waste due to the large kerf loss as well as achieving greater efficiency and better quality compared with conventional machining approaches. Experimental results show that compared with conventional-pulse voltage supply, the auxiliary-pulse voltage mode can avoid delay in electrical discharge during pulse-on time. Enhanced frequency of effective discharge for machining would increase machining speed, which would in turn reduce machining groove width, and obtain better surface roughness. In addition, parameters of significant influence on machining characteristics were examined with the Taguchi method, and the optimal combination levels of machining parameters were determined. In sum, our findings reveal that WEDM with auxiliary-pulse voltage supply is an effective approach to machining polysilicon with good quality and high efficiency achieved.     

Comparative study of conventional and micro WEDM based on machining of meso/micro Sized Spur Gear

This paper discusses the comparison of micro machining process using conventional and micro wire electrical discharge machining (WEDM) for fabrication of miniaturized components. Seventeen toothed miniaturized spur gear of 3.5 and 1.2 mm outside diameter were fabricated by conventional and micro WEDM respectively. The process parameters for both conventional and micro WEDM were optimized by preliminary experiments and analysis. The gears were investigated for the quality of surface finish and dimensional accuracy which were used as the criteria for the process evaluation. An average surface roughness (R_a) of 50 nm and dimensional accuracy of 0.1–1 μm were achieved in micro WEDM. Whenever applied conventional WEDM for meso/micro fabrication, a R_a surface roughness of 1.8 μm and dimensional accuracy of 2–3 μm were achieved. However, this level of surface roughness and dimensional accuracy are acceptable in many applications of micro engineering. A window of conventional WEDM consisting of low energy discharge parameters is identified for micromachining.     

Experimental investigation of the real-time micro-control of the WEDM process

The wire electrical discharge machining (WEDM) process has inherent instability due to its high complexity and stochastic characteristics. For more stable and efficient machining, the process must be actively controlled in real time while precisely determining the state of the instantaneous machining process. Feedback information when used in conjunction with an unstable discharge pulse ratio and instantaneous discharge energy can be applied to this micro-control system. This study presents the design and implementation of a system that fulfills these demands. Experimental results demonstrate that the proposed system is capable of simultaneously enhancing the machining stability, machining efficiency, and machining performance. For fine machining, the surface quality was enhanced by approximately 10 % without a loss of machining efficiency. Overall, both the feedrate and the surface roughness could be improved concurrently by more than 5 %.     

慢走丝电火花线切割粗加工仿真系统的开发

为对电火花线切割加工机理有更深刻的认识,了解加工参数对加工精度的影响规律,介绍了一个电火花线切割加工粗加工的仿真系统。仿真系统通过对放电点的探索、工件的去除以及对线电极丝振动的分析,将实际的加工现象形象地再现于计算机上。为证实仿真系统的正确性,将仿真结果与试验结果进行了比较。在试验结果的获取中,为能够得到很难测量的线电极周围的放电间隙和工件形状数据,提出一种新的三维形状测量方法。通过对仿真结果和试验结果的比较,定性地证明了仿真方法的正确性。研究结果表明:改变线电极张力及伺服电压值时,从仿真过程得到的加工形状结果与试验得到的加工形状结果其倾向基本一致;加工缝端部的形状呈凸形还是呈凹形,取决于加工过程中放电爆发力和静电引力的相对大小。     

The benefits of using instantaneous energy to monitor the transient state of the wire EDM process

This paper deals with the implementation and analysis of real-time energy monitoring of the transient state of the wire electrical discharge machining (WEDM) process. Recently, sparking frequency information has been applied to control of the WEDM process, making more stable and efficient machining. Experimental results, however, show the limitations and insufficiency of that method. Instead of using the sparking frequency monitoring method, the use of a real-time instantaneous energy monitoring system is suggested for interpreting the state of the WEDM process in more precise detail. The transient state of the WEDM process is analyzed in detail with the developed system, and a transient stability criterion of the WEDM process is suggested.