硬质合金电火花加工性能的试验研究

通过试验研究硬质合金的电火花加工中脉冲宽度、峰值电流等电参数对加工速度、电极损耗、加工表面粗糙度的影响规律,得出结论:脉冲宽度和峰值电流必须在一个合适的范围内才能得到较好的加工效果。     

激光超声复合加工硬质合金的切削特性研究

研究了激光加热与超声椭圆振动复合切削条件下,使用CBN(立方氮化硼)刀具对硬质合金材料进行精密加工的切削特性。利用有限元仿真,分析硬质合金材料在普通切削、一维超声振动切削、超声椭圆振动切削与激光超声复合切削4种切削方式下的切削力变化特征。采用超精密车床与YAG激光器、自主研发的超声振动装置等辅助设备,实验研究了激光超声复合精密加工硬质合金的切削特性。通过一系列的对比实验,分析切削参数,如切削速度、切削厚度,对切削力的影响规律。仿真与实验结果表明,由于加工材料的软化和断续切削,激光超声复合辅助加工显著地降低了切削力,硬质合金的切削加工性能得到显著改善,通过工艺参数的优化,可以实现硬质合金的精密加工。     

激光超声复合加工硬质合金的切削力理论与试验

为了实现硬质合金的延性域加工,研究激光加热与超声椭圆振动复合切削条件下,使用CBN(立方氮化硼)刀具对硬质合金进行精密加工的切削特性。分析硬质合金在普通切削、超声椭圆振动切削与激光超声复合切削三种切削方式下的切削力变化特征,建立激光超声复合切削的切削力理论模型,采用超精密车床与YAG激光器、自主研发的超声振动装置等辅助设备,试验研究激光超声复合精密加工硬质合金的切削特性。通过一系列的对比试验,分析切削参数,如切削速度、切削厚度对切削力的影响规律。理论模型与试验结果表明,由于硬质合金的软化和断续切削,使得激光超声复合辅助加工显著地降低了切削力,硬质合金的切削加工性能得到显著改善,通过工艺参数的优化,可以实现硬质合金的精密加工。     

典型材料的电火花线切割加工电参数差异研究

选取铝、调质45钢、硬质合金作为加工对比材料,在线切割机床EDM650上进行电参数能力对比试验.以粗糙度和效率作为衡量指标,考察脉冲宽度、脉冲间隔、功率管数(峰值电流)和空载电压对不同材料加工效果的影响.通过试验,得出了最佳参数组合,并分析3种材料的电参数可行选择范围和加工效果差异,可为相似材料的线切割加工提供参数选取实例依据.     

硬质合金钻头修磨与涂层技术的应用探索

针对HOWO被动锥齿轮加工中硬质合金钻头的使用,讨论了硬质合金钻头各相关参数对加工性能的影响,并且对各种不同的涂层材料进行了使用寿命对比试验。通过对刀具相关参数的优化,重磨技术和最新涂层技术的应用,将钻头使用寿命提高了数倍,明显降低了刀具成本。     

铌基合金切削加工过程中刀具优化研究

通过研究硬质合金和CBN刀具切削加工铌基合金材料过程中的加工性能,优化出适合铌基合金材料零部件超精密切削加工的刀具材料。通过硬质合金刀具在铌基合金材料切削加工过程中切削三要素(切削速度、进给量和切削深度)的正交切削加工试验,研究了其对切削加工表面粗糙度的影响,建立了硬质合金刀具切削加工铌基合金材料表面粗糙度预测模型,并利用AdvantEdge金属切削有限元仿真软件开展了切削工艺参数对切削加工过程的影响。     

ELID镜面磨削硬质合金的工艺参数实验研究

随着国防尖端技术的迅速发展,许多具有独特性能的新材料得到了日益广泛的应用,如光学玻璃、硬质合金。但采用传统磨削工艺加工这些材料很难得到良好的表面质量。在线电解砂轮修整(ELID)磨削技术是一项新的、高效的磨削方法,它有效地实现了许多难加工材料的超精密加工和高效加工。针对硬质合金的特性,用ELID磨削方法应用于硬质合金的精密加工,通过实验研究ELID磨削中工艺参数对加工表面的影响规律,找到了在一定条件下优化的工艺参数。     

涂层硬质合金刀具干式切削淬硬钢的试验研究

通过采用涂层硬质合金刀具对淬硬 4 5钢硬态干式切削试验 ,分析硬态干式切削淬硬钢的特点 ,研究了涂层硬质合金刀具及其几何参数的优化 ,讨论了涂层硬质合金刀具磨损形式、刀具耐用度及加工表面粗糙度 ,得出了可应用于实际干式切削加工的切削条件和参数     

电火花加工中电参数及热处理对加工质量影响的研究

电火花加工因性能优异而被广泛应用于航空航天、精密机械、汽车等行业的零部件加工中。选择38CrMoAlA和2Cr3WMoV两种材料,通过多组试验研究了电火花加工电参数及热处理工序对加工质量的影响,对不同参数、不同工序下的零件表面和断面进行了分析,为电火花加工时的电参数选择与热处理工序安排提供了参考。     

钛合金盒体的数控加工工艺研究

提出了钛合金材料的难加工特性、以及数控加工参数的选择等工艺难题,通过反复试验总结对数控加工参数、数控编程技术、刀具材料和参数进行优选,采用低转速、快速进给、小切削量和涂层硬质合金刀的数控加工方法,达到零件的加工工艺要求。     

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.     

Analysis of energy distribution during electric discharge machining of tungsten carbide

Abstract

During electrical discharge machining (EDM) process, electrical energy is used for the machining of the components. Energy distribution in electrical discharge machining process is the distribution of input energy supplied during machining to various components. In order to improve the technological performance during EDM process, it is essential to understand the distribution of input energy in the entire system. An experimental study on the effect of EDM energy distribution parameter for tungsten carbide is presented. The copper tungsten electrode has been used for the study. Experiments have been performed in specially designed dielectric insulated tank. To minimise the energy wastage, workpiece as well as the electrode was covered with Teflon. Current and pulse duration have been selected as variable parameters. The objective of this study is to analyse the amount of electrical energy used for machining effectively. The detail of this study has been presented in this paper.     

EDM of hybrid Al–SiCp–B4Cp and Al–SiCp–Glassp MMCs

Hybrid metal matrix composites are a class of material system, with two or more discrete particulate reinforcement. Notwithstanding their superior properties, their widespread application is constrained by the difficulty in machining them. Non-conventional processes such as electrical discharge machining can be applied to machine such composites. This work reports on the application of EDM to machine cast aluminum–silicon carbide–boron carbide and cast aluminum–silicon carbide–glass hybrid metal matrix composites and how the metal removal rate and surface finish vary in response to the various EDM parameters     

Study of the Batch Production of Micro Parts Using the EDM Process

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.     

Effect of processing parameters on structural features of tungsten carbide after electrical discharge machining (EDM)

Abstract

Tungsten carbide (WC) is an extremely hard material which is used extensively in the manufacturing of tools and dies. In the presence of cobalt as a binder its machining becomes a difficult task because of interfacial bonding. In the EDM process, where electrical energy is used for the machining of the substance, the heat generated due to the plasma is responsible for removal of the substance at the interface. The heat generated is conducted differentially because of the composite structure of the tungsten carbide cermet. In order to improve the technological performance it is essential to understand the morphological features of tungsten carbide after machining. The studies have been conducted using different machining parameters. The objective of this study is to analyse the impact of machining parameters on the morphology of tungsten carbide suitable to withstand impact load on press forging for small components during operation. Experiments have been performed with the specially designed fixtures with proper flushing arrangements, to avoid arcing during the process. WC of P20 grade which is one of the most suitable grade substances to withstand load after EDM, has been used as work piece material for the entire study. Copper, graphite and copper tungsten electrodes have been used for the present study. The morphological features were studied with the help of the scanning electron microscope (SEM). It was observed that structural features varied with variation in electrode under similar experimental conditions. Phenomenon of such structures is discussed at length. The formations of cracks on WC have also been studied in detail. The detail of this study is presented in the paper.     

Micro-hole Maching of Copper Using the Electro-discharge Machining Process with a Tungsten Carbide Electrode Compared with a Copper Electrode

This paper describes micro-hole machining of a copper plate using the electro-discharge machining (EDM) process. Tungsten carbide was selected as the material for the electrode and compared with a copper-electrode. A precision centreless grinding process was employed to grind the electrode down to the desired diameter. A series of experiments were performed on a traditional EDM machine to investigate the effects of electrode material polarity setting and of a rotating electrode. Results have shown that electrode wear and hole enlargement are both smaller when positive polarity machining is selected; whereas electrode wear is larger and machining speed is higher when negative polarity machining is selected. High-quality micro-hole machining in copper can be achieved by the proposed method.     

Modeling and analysis of the edge disintegration in the EDM drilling cobalt-bonded tungsten carbide

The characteristic feature of edge disintegration easily appears in the electric discharge machining (EDM) drilling processing of cobalt-bonded tungsten carbide (WC-Co). Such tendency reduces the strength against fatigue and results in a poor assembly tolerance. The objective of this paper was to present the mathematical models for modeling and analysis of the effects of process parameters, including the discharge current, pulse time on, duty factor, and capacitance value, on the disintegration factor at the entrance edge of drilled hole in the EDM drilling process of cobalt-bonded tungsten carbide. An experimental plan of a central composite design based on the response surface methodology (RSM) was employed to carry out the experimental study. The quadratic model of RSM associated with the sequential approximation optimization method was used to find the optimum settings of processing parameters. With the experimental values up to a 95% confidence interval, it is fairly well for the experimental results to present the mathematical model of disintegration factor. The results show that the interaction effect of discharge current with capacitance value has the greatest influence on the disintegration factor, followed by the capacitance value and the quadratic term of duty factor. The optimal settings of processing parameters obtained in this study represent the reduction of the 5.53% disintegration factor, which were compared with the results of initial processing parameters for drilling the cobalt-bonded tungsten carbide in the EDM process.     

Simultaneous optimisation of multiple performance characteristics in micro-EDM drilling of titanium alloy

Micro-electrical discharge machining (micro-EDM) has become a widely accepted non-traditional material removal process for machining conductive and difficult-to-cut materials effectively and economically. Being a difficult-to-cut material, titanium alloy suffers poor machinability for most cutting processes, especially the drilling of micro-holes using traditional machining methods. Although EDM is suitable for machining titanium alloys, selection of machining parameters for higher machining rate and accuracy is a challenging task in machining micro-holes. In this study, an attempt has been made for simultaneous optimization of the process performances like, metal removal rate, tool wear rate and overcut based on Taguchi methodology. Thus, the optimal micro-EDM process parameter settings have been found out for a set of desired performances. The process parameters considered in the study were pulse-on time, frequency, voltage and current while tungsten carbide electrode was used as a tool. Verification experiments have been carried out and the results have been provided to illustrate the effectiveness of this approach.     

Optimization of electrical discharge machining characteristics of WC/Co composites using non-dominated sorting genetic algorithm (NSGA-II)

Electrical discharge machining (EDM) is a process for shaping hard metals and forming deep and complex shaped holes by arc erosion in all types of electro conductive materials. In the present work, the effectiveness of the EDM process with tungsten carbide and cobalt composites is evaluated in terms of the material removal rate and the surface finish quality of the workpiece produced. The objective of this research is to study the influence of operating parameters of EDM such as pulse current, pulse on time, electrode rotation and flushing pressure on material removal rate and surface roughness. The experimental results are used to develop the statistical models based on second order polynomial equations for the different process characteristics. The non-dominated sorting genetic algorithm (NSGA-II) has been used to optimize the processing conditions. A non-dominated solution set has been obtained and reported.     

Optimization of machining parameters in rotary EDM process by using the Taguchi method

Electrical discharge machining (EDM) is one of the advanced methods of machining. Most publications on the EDM process are directed towards non-rotational tools. But rotation of the tool provides a good flushing in the machining zone. In this study, the optimal setting of the process parameters on rotary EDM was determined. A total of three variables of peak current, pulse on time, and rotational speed of the tool with three types of electrode were considered as machining parameters. Then some experiments have been performed by using Taguchi's method to evaluate the effects of input parameters on material removal rate, electrode wear rate, surface roughness, and overcut. Moreover, the optimal setting of the parameters was determined through experiments planned, conducted, and analyzed using the Taguchi method. Results indicate that the model has an acceptable performance to optimize the rotary EDM process.