往复走丝电火花线切割拐角加工控制策略的研究

电火花线切割加工广泛应用于模具制造、航空航天等领域,对其精度要求一直较高。通过拐角中最常见的直角作为突破点,对拐角误差产生的原因进行了系统分析;通过试验对厚度不同的工件进行了直角切割误差的研究,并根据电火花线切割加工的特点,采取不同的解决方案获得相关试验数据,优化电火花线切割的加工路径,使拐角误差与加工效率达到理想效果,最终通过实验对优化后的参数进行验证。     

消除线切割加工塌角现象简法

《电加工》1991年第4期上“高速走丝电火花线切割拐角加工”一文，阐明了高速走丝电火花线切割加工中塌角产生的原因，总结出克服塌角现象的几种切割工艺方法，其中一种是切割路径安排法。在长期的数控电火花线切割编程工作中，我对精度要求较高的零件在凸拐角处的切割工艺方法是：顺着拐角初始边的切割方向，越过拐角多切割出0．3m的长度，然后再顺着原路返回拐角处，接着按原程序切割，如图1。     

摇篮式电火花线切割机床运动学建模

传统"X-Y-U-V"式电火花线切割机床受限于几何结构,加上电极丝倾斜时不易保证良好的冲液条件,难以加工锥度大于30°的工件.为提高电火花线切割机床加工上下异型、大锥度等工件时的表面质量和尺寸精度,并拓展其应用范围,提出了工件摆动而电极丝不发生倾斜的摇篮式电火花线切割机床构型.首先,基于刚体运动学的基本理论,建立了用于...     

电火花线切割加工技术最新研究进展

介绍了近年来国内外电火花线切割加工技术的最新研究进展,包括加工变厚度工件过程中工件厚度的在线辨识及参数优化与控制,提高加工拐角精度电极丝偏差的在线检测,基于浮动阀值的放电间隙状态检测技术,在机床加工中表面质量修正技术以及混粉对提高加工质量以及加工效率的研究等.     

影响慢走丝线切割表面质量及断丝的工艺性因素分析

分析了影响慢走丝电火花线切割加工工件表面质量和引起断丝的主要工艺因素 ,指出了提高线切割加工工件精度和表面质量的有效方法 ,提出了防止断丝的措施     

消除线切割加工塌角现象简法

《电加工》1991年第4期上“高速走丝电火花线切割拐角加工”一文,阐明了高速走丝电火花线切割加工中塌角产生的原因,总结出克服塌角现象的几种切割工艺方法,其中一种是切割路径安排法。在长期的数控电火     

摇篮式电火花线切割机床运动学建模

传统“X-Y-U-V”式电火花线切割机床受限于几何结构,加上电极丝倾斜时不易保证良好的冲液条件,难以加工锥度大于30°的工件。为提高电火花线切割机床加工上下异型、大锥度等工件时的表面质量和尺寸精度,并拓展其应用范围,提出了工件摆动而电极丝不发生倾斜的摇篮式电火花线切割机床构型。首先,基于刚体运动学的基本理论,建立了用于求解机床各轴数控指令的运动学模型;接着,引入机床几何误差进行精度建模,推导该误差至加工表面的映射关系,并依据此模型对数控指令进行误差补偿;最后,通过实验验证所提出的摇篮式电火花线切割机床加工上下异型、大锥度等工件的可行性。     

往复走丝线切割机床变厚度切割工艺研究

电火花线切割机床在加工变厚度工件时,工件厚度变化处易出现加工条纹,影响加工质量和加工效率,而根据不同厚度的工件采用不同的加工参数,可明显改善加工质量和效率。利用往复走丝电火花线切割机床进行不同厚度工件的加工试验研究,采用正交试验法进行规划,并对试验结果进行分析,研究其加工规律,分析得到加工变厚度工件的理想参数,从而实现电火花线切割加工变厚度工件时始终保持较高的加工效率及一致的表面质量。     

电火花线切割拐角加工精度的实时预测

提出了一种电火花线切割加工拐角加工精度的实时预测方法,并为此建立了实时预测系统.系统根据实时采集的放电能量等加工参数,通过电极丝振动解析及数控轨迹与电极丝位置关系的分析,可得出电极丝形变量与加工误差,从而可将拐角加工形状实时地再现于计算机上,实现了拐角加工精度的实时预测.     

供液方式对电火花线切割极间流场的影响分析

在电火花线切割加工过程中,放电间隙内工作液的流动状况对加工效率和加工质量具有重要影响。为此,建立了电火花线切割放电间隙的三维几何模型,运用COMSOL有限元分析软件对不同供液方式下的电火花线切割极间流场进行了数值模拟分析。结果表明:浸液式高速走丝加工和喷液式高速走丝加工的排屑、散热效果优于喷液式低速走丝加工,且浸液式高速走丝加工能切割大厚度工件。     

电火花线切割加工表面微织构技术研究

表面微织构加工是一个相当复杂的过程,涉及微织构的尺寸、质量及形貌等问题。为解决制备微织构存在的问题,利用数控电火花线切割加工技术,在45钢表面加工微槽织构,研究线切割制备微织构的尺寸、形貌。试验分别采用钼丝、铜丝作为电极丝,设计脉宽、脉停、电流等线切割正交试验,切割宽度小于400μm的微槽织构,分析不同线切割参数、电极丝材料对微槽尺寸精度和微槽切口处光整度的影响。通过采集、测量试验所得工件表面微槽织构,发现线切割参数对微槽尺寸精度和切口处光整度有较大的影响;在较小线切割参数下,钼丝切割的微槽尺寸大于铜丝,在较大的线切割参数下,铜丝切割的微槽尺寸大于钼丝;对比微槽切口处光整度,发现钼丝切割的微槽整体质量优于铜丝。试验列出不同线切割参数切割的微槽尺寸,为电火花线切割加工微织构提供了试验数据。     

Effect of Wire Material on Productivity and Surface Integrity of WEDM-Processed Inconel 706 for Aircraft Application

Inconel 706 is a recently developed superalloy for aircraft application, particularly in turbine disk which is among the most critical components in the gas turbine engines. Recently, wire electrical discharge machining (WEDM) attained success in machining of gas turbine components which require complex shape profiles with high precision. To achieve the feasibility in machining of these components, the research work has been conducted on Inconel 706 superalloy using WEDM process. And, the effect of different wire materials (i.e., hard brass wire, diffused wire, and zinc-coated wire) on WEDM performance characteristics such as cutting speed, surface topography, surface roughness, recast layer formation, residual stresses, and microstructural and metallurgical alterations have been investigated. Even though, zinc-coated wire exhibits improved productivity, hard brass wire was found to be beneficial in terms of improved surface quality of the machined parts. Additionally, lower tensile residual stresses were obtained with hard brass wire. However, diffused wire has a moderate effect on productivity and surface quality. Under high discharge energy, higher elemental changes were observed and also the white layer was detected.     

微细丝数控电火花线切割加工机床的设计

以加工微小复杂零件为目标,对采用直径0.02 mm的微细电极丝进行数控电火花微精线切割加工技术及工艺研究,开发出了由微细丝走丝系统、细丝导向器和微精加工电源等构成的微细电火花线切割加工系统,研制了具有无电阻防电解电源、高效、高精度、高表面质量的微细丝数控单向走丝电火花线切割机床。     

静叶片内背弧型面线切割电极丝温度场分布规律研究

基于静叶片型面的线切割加工,根据Fourier热传导理论和叠加原理,将电极丝温度场分布进行合理的简化,可得电极丝温度场分布变化,结合实际静叶片线切割后型腔表面粗糙度、电极丝损耗、切割速度等工艺指标进行分析,修正相关加工参数。试验结果表明:通过模拟电极丝温度场分布情况,对电加工参数进行调整,能有效降低电极丝损耗。     

慢走丝机床的走丝性能研究

慢走丝机床是模具、形状复杂和精密细小工件的主要加工设备之一,特别是在硬质合金等高硬度材料的加工中更为重要。慢走丝的走丝系统是决定加工质量的关键因素之一。本文介绍了慢走丝机床的走丝系统结构组成:贮丝系统、张力控制系统、位置导向控制系统、收丝系统和碎丝系统。分析了影响走丝稳定性的收丝轮压力、丝张力和冲水压力等三个关键因素及其参数选取。分析了收丝轮的材料选取和制作加工工艺。制作的收丝轮性能达到使用要求,成本仅为原来的2%。     

State of the art in wire electrical discharge machining (WEDM)

Wire electrical discharge machining (WEDM) is a specialised thermal machining process capable of accurately machining parts with varying hardness or complex shapes, which have sharp edges that are very difficult to be machined by the main stream machining processes. This practical technology of the WEDM process is based on the conventional EDM sparking phenomenon utilising the widely accepted non-contact technique of material removal. Since the introduction of the process, WEDM has evolved from a simple means of making tools and dies to the best alternative of producing micro-scale parts with the highest degree of dimensional accuracy and surface finish quality.Over the years, the WEDM process has remained as a competitive and economical machining option fulfilling the demanding machining requirements imposed by the short product development cycles and the growing cost pressures. However, the risk of wire breakage and bending has undermined the full potential of the process drastically reducing the efficiency and accuracy of the WEDM operation. A significant amount of research has explored the different methodologies of achieving the ultimate WEDM goals of optimising the numerous process parameters analytically with the total elimination of the wire breakages thereby also improving the overall machining reliability.This paper reviews the vast array of research work carried out from the spin-off from the EDM process to the development of the WEDM. It reports on the WEDM research involving the optimisation of the process parameters surveying the influence of the various factors affecting the machining performance and productivity. The paper also highlights the adaptive monitoring and control of the process investigating the feasibility of the different control strategies of obtaining the optimal machining conditions. A wide range of WEDM industrial applications are reported together with the development of the hybrid machining processes. The final part of the paper discusses these developments and outlines the possible trends for future WEDM research.     

The surface characteristics of P/M high-speed steel (ASP 23) multi-cut with wire electrical discharge machine (WEDM)

High-speed steel (ASP 23), which was made by powder-metallurgy (P/M) process and widely used as the material for IC-packaging mold was subjected to multi-cutting with wire electrical discharge machine (WEDM) by using a brass wire electrode. Before WEDM, the steel was quenched at 1180 °C and then three-times tempered at 560 °C to acquire suitable mechanical properties. The cut surface was examined with scanning electron microscope (SEM) and analyzed with anodic polarization measurement in 1 M CH₃COOH. The results show that surface alloying between the steel and wire electrode materials was observed in the recast layer; meanwhile, martensitic transformation can be found. Surface alloying and phase transformation of the cut surface can be characterized with their anodic polarization curves measured in 1 M CH₃COOH. An obvious passive current can be detected in the martensitic structure by anodic polarization curve in higher overpotential, while such passive current did not occur in the tempered structure. A wide potential range corresponding to the potential range of passive current and higher breakdown potential of the anodic polarization curve was found on the cut surface after WEDM. This effect was caused by surface alloying in the recast layer and martensitic transformation in the workpiece adjacent to the cut surface.     

TiNi形状记忆合金的电火花加工性能

TiNi形状记忆合金由于具有优异的超弹性和形状记忆效应等性能而被大量地应用于工业生产中。然而,形状记忆合金的传统加工相当复杂。因此,研究TiNi形状记忆合金的电火花线切割加工（WEDM）性能。采用L27正交阵列以尽量减少实验。在不同的脉冲持续时间、脉冲关断时间、伺服电压、冲洗压力和线速度条件下进行实验。为同步优化提出一种利用Taguchi设计与实用理念的多响应优化方法。通过对信噪比（S/N）的均值分析和方差分析,确定最佳参数水平。Taguchi分析表明：1μs脉冲持续时间、3.8μs脉冲关断时间、40 V伺服电压、1.8×105Pa冲洗压强和8 m/min线速度,有利于同时使材料去除率最大化和表面粗糙度最小化。TiNi形状记忆合金电火花线切割加工的优化结果表明：脉冲持续时间显著影响材料去除率和表面粗糙度。在较长的脉冲持续时间时,在加工表面可观察到放电坑、微裂纹和重铸层。     

基于Pro/E的电火花线切割曲面加工仿真软件开发

阐述了一种用于4轴联动电火花线切割曲面加工的CAD／CAM仿真软件，该软件以Pro／E为开发平台，利用Pro／E自身的二次开发工具TOOLKIT并结合VC＋＋6．0进行二次开发。该仿真软件根据电火花线切割加工的特点，从CAD曲面模型获取加工轨迹点数据，计算出电极丝的位姿，进而生成机床进行曲面加工所需要的NC指令代码，并可在毛坯模型中仿真曲面加工过程。     

稳定电极丝空间形位的一种有效方法

高速走丝电火花线切割加工时电极丝的形位变化较大，严重影响线切割加工的稳定性和加工精度。如何稳定电极丝的空间形位，是高速走丝线切割加工亟待解决的课题。作者在大量试验研究的基础上，开发了一种高耐磨性的导向装置，能有效地稳定电极丝的空间形位，提高线切割加工稳定性和加工精度。