数控电火花线切割加工参数优选的试验研究

针对数控高速走丝电火花线切割加工中的电参数的选取,本文运用二次通用旋转组合设计方法进行了工艺数据试验,提出了针对人工神经网络建模的数据预处理方法,建立了基于BP神经网络的电火花线切割加工参数模型。该模型可有效地反映高速走丝电火花线切割加工的工艺规律,实现在指定加工要求下的加工参数的优化选取。     

模糊神经网络在电火花线切割加工中的应用

分析了电火花线切割加工工艺特点,针对其加工过程的复杂,各工艺参数之间相互制约,难以用传统的数学方法解决,而提出了用模糊神经网络对电火花线切割加工过程建立模型,通过网络的训练,实现加工参数的优化选取和预测,并且提取出有效的规则集.实验结果说明了这一方法具有可行性和实用性,并取得了较好的效果.     

灰色理论在慢走丝线切割加工中的应用

慢走丝电火花线切割中工艺指标与工艺参数之间具有高度非线性关系,难以实现电火花多工艺参数优化,针对此问题,以电火花线切割SKD11模具钢为试验对象,选用水压、脉冲宽度、脉冲间隔、峰值电流和进给速度为可变因素,表面粗糙度(Ra)和材料去除率(MRR)为工艺指标,设计田口试验,采用灰色关联分析方法研究加工参数对工艺指标的影响关系;建立改进的灰色神经网络模型对Ra和MRR预测,其平均相对误差分别为7.92%和8.13%。结果表明,该模型能反映出电火花线切割SKD11模具钢的工艺规律并能成功预测出Ra和MRR,为电火花线切割SKD11模具钢工艺参数的选择提供了依据。寻找的一组优化参数对SKD11模具钢的线切割加工具有一定的参考意义。     

电火花线切割五轴联动加工运动规律及仿真研究

为研究空间曲面的加工过程和规律,提出电火花线切割五轴加工计算机仿真技术研究方法.分析了空间曲面电火花线切割加工的特点及运动规律,建立了电火花线切割多轴加工系统运动的数学模型.通过运行相应的仿真程序,可以在计算机上直接观察到电火花线切割加工的全部过程,获得了比较理想的仿真结果.仿真所得到的理想加工参数为复杂零件加工提供了理论基础.从而拓宽了电火花线切割加工的工艺范围,解决了空间曲面零件的加工难题.     

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。     

电火花线切割机床工艺参数优化数据库系统

论述了电火花线切割机床加工过程中电源波形和电参数对工艺指标的影响，以及电极丝对工艺效果的影响，并分析了断丝原因。应用Visual FoxPro6.0建立了“电火花线切割机床工艺参数优化数据库系统”。     

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。     

基于正交试验和BP神经网络的Ti-6Al-4V合金电火花线切割工艺参数优化

针对切削性能差难以加工的Ti-6Al-4V合金进行了电火花线切割加工试验研究,运用正交试验的方法对工艺数据进行极差、方差分析,探究电火花线切割加工的规律和特性。重点分析脉冲宽度、脉冲间隔、功放管数和运丝速度等工艺参数对钛合金加工质量的影响,取得了线切割最优化参数组合。搭建了基于L-M优化算法的BP神经网络的线切割加工工艺网络预测模型,该模型训练速度快、预测精度高,可为Ti-6Al-4V合金的切割提供可靠的加工质量预测,对实际加工的参数选择具有一定的参考作用。     

电火花线切割加工工艺指标的影响因素及其改进措施的研究

电火花线切割机床对零件的加工精度(主要指加工的形状精度和位置精度)不仅与机床固有的结构设计精度和精度保持性有一定的直接关系,放电过程控制的好坏也直接影响到加工性能的优劣.阐述了电火花线切割的工艺指标,分析了电参数和非电参数等方面对工艺指标的影响,并针对这些因素提出了提高电火花线切割加工质量的有效方法及生产过程中的注意事项.     

提高电火花线切割加工精度的几种因素的探讨

通过对数控快走丝电火花线切割加工原理的理解,介绍了影响线切割机床加工精度的几种因素,如:主要工艺指标、放电参数、走丝系统,工作液及其解决方案。     

An experimental investigation on machining parameters of AISI D2 steel using WEDM

The performance of the wire electrodischarge machining (WEDM) machining process largely depends upon the selection of the appropriate machining variables. Optimization is one of the techniques used in manufacturing sectors to arrive for the best manufacturing conditions, which are essential for industries toward manufacturing of quality products at lowest cost. As there are many process variables involved in the WEDM machining process, it is difficult to choose a proper combination of these process variables in order to maximize material removal rate and to minimize tool wear and surface roughness. The objective of the this work is to investigate the effects of process variables like pulse on time, pulse off time, peak current, servo voltage, and wire feed on material removal rate (MRR), surface roughness (SR), gap voltage, gap current, and cutting rate in the WEDM machining process. The experiment has been done using Taguchi’s orthogonal array L27 (3⁵). Each experiment was conducted under different conditions of input parameters and statistically evaluated the experimental data by analysis of variance (ANOVA) using MINITAB and Design Expert tools. The present work also aims to develop mathematical models for correlating the inter-relationships of various WEDM machining parameters and performance parameters of machining on AISI D2 steel material using response surface methodology (RSM).The significant machining parameters and the optimal combination levels of machining parameters associated with performance parameters were also drawn. The observed optimal process parameter settings based on composite desirability (61.4 %) are pulse on time 112.66 μs, pulse off time 45 μs, spark gap voltage 46.95 V, wire feed 2 mm/min, peak current of 99.99 A for achieving maximum MRR, gap current, gap voltage, cutting rate, and minimum SR; finally, the results were experimentally verified.     

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.     

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。     

On wire breakage and microstructure in WEDC of SiCp/6061 aluminum metal matrix composites

Unconventional machining like wire electric discharge machining/cutting (WEDM/WEDC) seems to be a better choice for machining/cutting the metal matrix composites (MMCs) because it offers easy control and has the capability of machining intricate complex shapes. But wire breakage in the WEDM/WEDC process decreases the machining accuracy and the quality of the machined surface. This paper describes the effect of four input process parameters (i.e., servo voltage, pulse-on time, pulse-off time, and wire feed rate) on wire breakage frequency and the microstructure of the cut surface during WEDC of SiC_p/6061 Al MMC. An optimum range of input parameters has been bracketed as the outcome of this work for determining the effects of input process parameters on the average cutting speed, material removal rate, and surface roughness during WEDC of SiC_p/6061 Al MMC. This range of input parameters can also be used for carrying out further research to develop the models for WEDC of SiC_p/6061 Al MMC and to optimize the WEDC parameters for smooth cutting.     

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.     

Modeling and multiresponse optimization on WEDM for HSLA by RSM

Wire electric discharge machining (WEDM) is a nonconventional machining method to cut hard and conductive material with the help of a moving electrode. High-strength low-alloy steel (HSLA) is a hard alloy with high hardness and wear-resisting property. The purpose of this study is to investigate the effect of parameters on cutting speed and dimensional deviation for WEDM using HSLA as workpiece. It is seen that the most prominent factor for cutting speed and dimensional deviation is pulse-on time, while two-factor interactions play an important role in this analysis. Response surface methodology was used to optimize the process parameter for cutting speed and dimensional deviation. The central composite rotatable design was used to conduct the experiments. The analysis of variance was used for the investigation of significant factors.     

Determining cutting parameters in wire EDM based on workpiece surface temperature distribution

The material removal process in wire electrical discharge machining (WEDM) may result in work-piece surface damage due to the material thermal properties and the cutting parameters such as varying on-time pulses, open circuit voltage, machine cutting speed, and dielectric fluid pressure. A finite element method (FEM) program was developed to model temperature distribution in the workpiece under the conditions of different cutting parameters. The thermal parameters of low carbon steel (AISI4340) were selected to conduct this simulation. The thickness of the temperature affected layers for different cutting parameters was computed based on a critical temperature value. Through minimizing the thickness of the temperature affected layers and satisfying a certain cutting speed, a set of the cutting process parameters were determined for workpiece manufacture. On the other hand, the experimental investigation of the effects of cutting parameters on the thickness of the AISI4340 workpiece surface layers in WEDM was used to validate the simulation results. This study is helpful for developing advanced control strategies to enhance the complex contouring capabilities and machining rate while avoiding harmful surface damage.     

Fabricating micromilling tool using wire electrodischarge grinding and focused ion beam sputtering

In the present research, wire electrical discharge machining (WEDM) of γ titanium aluminide is studied. Selection of optimum machining parameter combinations for obtaining higher cutting efficiency and accuracy is a challenging task in WEDM due to the presence of a large number of process variables and complicated stochastic process mechanisms. In general, no perfect combination exists that can simultaneously result in both the best cutting speed and the best surface finish quality. This paper presents an attempt to develop an appropriate machining strategy for a maximum process criteria yield. A feed-forward back-propagation neural network is developed to model the machining process. The three most important parameters – cutting speed, surface roughness and wire offset – have been considered as measures of the process performance. The model is capable of predicting the response parameters as a function of six different control parameters, i.e. pulse on time, pulse off time, peak current, wire tension, dielectric flow rate and servo reference voltage. Experimental results demonstrate that the machining model is suitable and the optimisation strategy satisfies practical requirements.     

Analyzing the surface layer after WEDM depending on the parameters of a machine for the 16MnCr5 steel

The efficient wire electric discharge machining (WEDM) technology is a trade-off between the cutting speed and the resulting surface quality. A typical morphology of a surface machined using WEDM contains a large number of craters caused by the electric sparks generated in the cutting process. The paper analyzes the influence of the cutting speed on the quantitative and qualitative evaluation of the craters formed on the surface of a workpiece made of the 16MnCr5 steel. Applying metallography to cross-section microscopic slides, diffusion subsurface damages were studied caused by the cutting. The diffusion processes taking place between the electrode and the material machined were studied using a local point EDX microanalysis applied both to the machined surfaces and to the cross sections. A detailed study was also carried out of the brass electrode to measure its wear rate caused by the cutting process as well as its degradation in terms of the quality of its morphology and the chemical composition of surface.