聚晶金刚石电火花超声机械复合加工技术研究

聚晶金刚石具有优良的力、热、化学、声、光、电等性能,在现代工业、国防等领域中得到日益广泛的应用。但是,聚晶金刚石硬度高,耐磨性好,其成型加工非常困难,超声电火花机械复合加工技术是一种有效的加工方法。本研究在分析电火花超声机械复合加工原理的基础上,采用青铜结合剂金刚石砂轮实现了聚晶金刚石的超声电火花机械复合加工。实验分析了超声电火花机械复合加工过程工艺参数与加工效果之间的关系,结果表明,脉宽、脉间、峰值电流、超声振幅、开路电压等参数对复合加工过程工艺结果的影响程度较明显。     

基于神经网络的电火花成形加工参数优选系统

建立了电火花成形加工的神经网络模型，应用其实现了指定加工条件下的工艺效果精确预测，在此基础上进一步建立了电火花成形加工参数的优选模型和优选系统，该系统充分结合了神经网络优化模型和工艺数据库各自的优点，可得到指定加工要求焉得虎子机床能达到的最优加工参数组合，解决了单纯基于工艺数据库的加工参数选取系统所存在的有限的工艺参数组合与多变的加工条件之间的矛盾。     

钛合金深小孔精微电火花加工工艺研究

对钛合金深小孔的电火花加工工艺进行了深入的研究。优选了电火花加工放电参数;应用了超声复合和削边电极等工艺手段。通过研究,极大地提高了加工速度和加工质量。     

基于信噪比的微小孔加工工艺参数的分析方法

加工工艺参数准确合理的分析方法是优化组合电火花微细加工中多目标工艺参数的重要前提和保证。文章利用参数设计中的信噪比方法对电火花微小孔加工过程中的工艺参数进行分析研究，得到电火花微小孔加工过程中关键参数单因子工艺指标的优化分析结果，从而达到对电火花微小孔加工工艺参数进行单因子优化设计的目的，为多目标工艺参数综合优化组合提供重要的数据支持。试验结果表明信噪比分析方法能够较好地解决电火花微细加工中的关键工艺参数优化问题，对加工效率和加工精度有一定的改善和提高。     

方波脉冲电源超声电火花复合加工试验研究

本文总结了采用晶体管方波脉冲电源进行超声电火花复合加工的试验情况。对该工艺的合理加工参数及适用范围作了论证,初步探讨了超声在电火花加工中的作用机理。在加工精微小孔、异形孔及窄缝的加工实例中,取得了超声电火花复合精微加工成倍提高生产率的工艺效果。     

复杂型面的复合光整加工实验研究

利用电火花-超声和脉冲电化学复合加工工艺对三维复杂型面的光整加工进行了研究,论述了电火花超声复合加工的原理及超声装置的设计,进行了工艺参数实验研究,通过Master CAM软件实现型面的造型、编程,进行了三维型面的精密成形加工,经过脉冲电化学抛光后使型面达到镜面效果.     

硬质合金的超声电火花复合加工速度研究

通过采用电火花加工和超声电火花复合加工的方法加工硬质合金的试验,分析超声电火花复合加工应用的限制因素,研究脉冲宽度、峰值电流等参数对加工速度的影响。结果表明,在一定的条件下超声电火花复合加工比普通电火花加工效率高、表面质量好,可用于硬质合金模具的加工。     

聚晶金刚石电火花磨削加工效果预测和加工参数优化仿真系统

建立了聚晶金刚石电火花磨削加工效果预测及加工参数优化仿真系统，可以预测聚晶金刚石电火花磨削加工后的效果，具有较高的精度，并能实现加工参数的优化，进行优势因素分析。通过工艺数据库的建立，该仿真系统可以适用于各种材料的加工工艺，有助于进一步提高聚晶金刚石加工的自动化程度和开发智能化系统。     

混粉电火花加工技术在粗加工中的应用研究

在对混粉电火花加工机理进行系统研究的基础上，对混粉电火花粗加工中的加工效率和加工表面粗糙度进行了实验研究。结果表明，通过合理选择放电参数，混粉电火花加工在相近加工表面粗糙度时，能显著提高加工效率，从而为混粉电火花加工技术在粗加工中应用提供依据。     

混粉电火花镜面加工技术及应用

利用自行研制的混粉电火花镜面加工装置，对混粉电火花镜面加工影响因素，加工表面性能等进行了深入研究，找出了粉末特性，工件材料，粉末浓度及放电参数等对混粉电火花镜面加工的影响规律，给出了合理的混粉电火花镜面加工工艺条件，以文中确定的加工工艺条件对铸造和压铸模具进行混粉电火花镜面加工，结果表明，该技术能提高模具制造质量，降低工人劳动强度，缩短模具制造周期。     

An investigation of ultrasonic-assisted electrical discharge machining in gas

This study focuses on using ultrasonic to improve the efficiency in electrical discharge machining (EDM) in gas medium. The new method is referred to as ultrasonic-assisted electrical discharge machining (UEDM). In the process of UEDM in gas, the tool electrode is a thin-walled pipe, the high-pressure gas medium is applied from inside, and the ultrasonic actuation is applied onto the workpiece. In our experiment, the workpiece material is AISI 1045 steel and the electrode material is copper. The experiment results indicate that (a) the Material Removal Rate (MRR) is increased with respect to the increase of the open voltage, the pulse duration, the amplitude of ultrasonic actuation, the discharge current, and the decrease of the wall thickness of electrode pipe; and (b) the surface roughness is increased with respect to the increase of the open voltage, the pulse duration, and the discharge current. Based on experimental results, a theoretical model to estimate the MRR and the surface roughness is developed.     

Material removal mechanisms of cemented carbides machined by ultrasonic vibration assisted EDM in gas medium

A new electrical discharge machining (EDM) technology named tool electrode ultrasonic vibration assisted electrical discharge machining in gas medium (UEDM in gas) is proposed and its principle is introduced. Relevant experimental equipment was designed by which a series of machining experiments of cemented carbide material were carried out. The mechanisms of cemented carbide material removal are discussed in detail through observing and analyzing the microstructures of machined surface. Five material removal mechanisms of cemented carbides machined by UEDM in gas were proposed, which are melting and evaporation, oxidation and decomposition, spalling, the force of high-pressure gas and the affection of ultrasonic vibration.     

超声振动辅助气中放电加工实验分析

超声振动辅助气中放电加工技术避免了常用的煤油等工作液作为介质带来的环境污染问题，具有工作环境清洁、适用范围广、加工效率高、工具电极简单等优点。实验研究了电压、脉冲宽度、峰值电流、超声振幅及气体介质压力等参数对加工效率、工件表面粗糙度及电极损耗的影响．并对试验结果进行了分析。     

Experimental investigation into electrochemical micromachining (EMM) process

Due to several advantages and wider range of applications, electrochemical micromachining (EMM) is considered to be one of the most effective advanced future micromachining techniques. A suitable EMM setup mainly consists of various components and sub-systems, e.g. mechanical machining unit, micro-tooling system, electrical power and controlling system and controlled electrolyte flow system etc. have been developed successfully to control electrochemical machining (ECM) parameters to meet the micromachining requirements. Investigation indicates most effective zone of predominant process parameters such as machining voltage and electrolyte concentration, which give the appreciable amount of material removal rate (MRR) with less overcut. The experimental results and analysis on EMM will open up more application possibilities for EMM.     

专家系统在超声-放电复合加工机床上的应用

利用专家系统解决超声-放电复合加工中选择参数的问题。介绍了超声-放电复合加工参数选择专家系统的结构及其在机床控制系统中的作用。     

超声复合电加工振动参数检测控制与试验研究

利用高速、高精激光微位移传感器及高频数字示波器进行超声及其复合加工的振动参数(振幅与频率)在线测量,其结果具有高精度和实时性。设计了控制软件,为保持超声振动的稳定及复合电加工参数的在线实时调节与优化建立了基础条件,同时通过数学处理得到了超声振幅与超声激振电压之间的关系。利用分析与测试结果合理选择加工参数,对陶瓷、硬质合金等硬脆性难加工材料进行了超声及其复合电加工试验,超声振动系统工作稳定可靠,试验结果验证了超声及其复合电加工技术对硬脆难加工材料的加工优势。     

工程陶瓷引弧微爆炸加工技术参数分析及性能特点

从系统组成、工作原理、工艺参数、技术特点等方面,介绍了一种新开发的适用于工程陶瓷材料粗加工的引弧微爆炸加工技术,分析了影响加工过程的典型工艺参数,总结了该技术的性能特点。引弧微爆炸加工系统的主要部件为专用脉冲电源及微爆炸发生器,系统工作时生成的微爆炸等离子体射流具有高温高压特性,作用于陶瓷材料表面生成一个圆形蚀坑。加工过程中的工艺参数主要包括喷嘴孔径、工作电流、工作气压、工作脉宽及工作距离。该技术具有低成本、工艺灵活、热损伤小、加工范围广及加工后表面粗糙等特点。     

微小整体构件加工技术的现状和发展

介绍了微小整体构件制造技术的现状,对数控切削、特种加工、精密铸造等加工工艺方法做出了相应比较.重点论述了以数控电解、数控电火花为加工代表的特种加工技术对微小整体构件的加工,以此为基础,阐明了组合/复合加工技术有望在未来制造中发挥更重要的作用.最后对微小整体构件的发展趋势及应用前景进行了展望.     

Analytical model to determine the critical feed per edge for ductile-brittle transition in milling process of brittle materials

Brittle materials like glass are considered difficult-to-machine because of their high tendency towards brittle fracture during machining. The technological challenge in machining such brittle materials is to achieve material removal by plastic deformation rather than characteristic brittle fracture. In ductile mode machining, the material is removed predominantly by plastic deformation and any cracks produced due to possible fracture in the cutting zone are prevented from extending into the machined surface. This is achieved by selecting an appropriate cutting tool and suitable machining parameters. In ductile machining by milling process, fracture induced cracks are diverted away from final machined surface by selecting a suitable feed per edge less than a critical threshold value. Hence determination of critical feed per edge is of paramount importance to achieve ductile mode machining by milling process. This paper presents an analytical model based on fracture mechanics principles to predict the critical feed per edge in milling process of glass. The size and orientation of cracks originating from brittle fracture during machining have been quantified by using indentation test results and the critical value of feed per edge has been determined analytically as a function of intrinsic materials properties governing brittle fracture and plastic deformation. Furthermore, an equivalent tool included angle has been suggested for machining operation as against the indenter included angle to correlate the indentation and machining test results with improved degree of accuracy. Experimental results validated the proposed model fairly accurately. It has been established that if the longest cracks oriented in radial direction to the cutting edge trajectory are prevented from reaching the final machined surface by selecting a feed per edge less than or equal to a critical value, a crack-free machined surface can be achieved.     

基于柔度耦合子结构法的主轴-卡盘与工件结合面参数辨识

车削加工系统振动特性参数的获得对加工精度和加工质量的控制、加工参数选择有重要意义,主轴-卡盘子结构和工件子结构结合面参数难以精确测量和解析计算。基于柔度耦合子结构法(RCSA)建立车床主轴-卡盘-工件系统工件自由端频响函数的预测模型,用遗传算法对加工系统锤击激励模态实验频响函数与其频响函数模型预报值的相对误差进行目标函数寻优,辨识出子结构间的结合面参数。结果表明:预测模型与锤击激励模态实验获得加工系统工件自由端频响函数有较好的一致性,该辨识方法可应用于车削工件表面加工精度和加工质量的控制。