水射流钻曲面导流轮的电火花展成加工

对用数控电火花成形机床展成加工锥形水射流钻螺旋曲而导流轮的方法进行研究，分析了展成加工中电极与工件干涉而导致的过切问题，并给出解决干涉现象的展成电机修正设计方法．     

航空发动机整体叶盘磨料水射流开坯加工技术研究进展

整体叶盘结构是航空发动机技术发展的一个重要方向，且多采用难加工材料，如何实现整体叶盘高质高效加工是机械制造领域亟待解决的难题之一。通过高压磨料水射流（AWJ）加工技术实现整体叶盘毛坯的开坯粗加工，是一种有效缩短整体叶盘加工周期、降低昂贵铣削刀具成本、提高开坯效率的工艺手段。本文就磨料水射流加工材料去除机理、复杂曲面轨迹优化、多物理量和机械量参数组合优化和整体叶盘开坯设备概述了国内外的研究现状，在此基础上，针对当前具有复杂曲面结构的整体叶盘开坯面临的关键问题，提出了若干解决思路和技术途径，指出了高压磨料水射流在复杂曲面零件高效加工中的发展趋势。     

基于颗粒水射流的异型不锈钢元件确定性加工

基于颗粒水射流材料去除性能稳定、无刀具磨损、复杂面形适应能力强等优点,提出了基于确定性修形的异型不锈钢元件加工方法,确定了适用于不锈钢元件表面的测量方法,对其加工路线进行了规划。对于齿形"窄"环带表面经过3次确定性修形加工后,表面面形Rms由初始的9.774Wave(1Wave=632nm)收敛至2.009Wave,表面质量提升明显,表面粗糙度减少至63.303nm,达到加工要求。实验结果表明颗粒水射流加工对不锈钢件加工具有优良的确定性修形能力,具有广泛的应用前景。     

序言

特种加工技术是区别于传统制造方法,利用电、光、热、声、化学等能量或其组合来实现零部件几何尺寸、表面质量或形状特征改变的加工方法,主要包括放电加工、电化学加工、激光加工、离子束/电子束加工、超声加工、增材制造、水射流加工等. 特种加工技术由于其独特优势,已成为先进制造技术体系中不可或缺的重要组成部分,尤其是在航空航天领域...     

陶瓷基复合材料不同加工工艺的表面形貌分析研究

主要对比分析了机械加工、高压水射流加工、激光加工的3种不同加工工艺对SiCf/SiC复合材料表面形貌的影响。结果显示机械加工与高压水射流加工表面孔洞和微裂纹均较多,水切割表面呈现出纤维拔出状态;空气环境中激光加工的表面平整,出现了封孔特征,孔洞和微裂纹数量少,氮气环境中激光加工的表面形貌生长了一层SiC晶粒,可起到愈合表面孔洞和微裂纹的作用。     

复合材料的加工工艺与连接技术

介绍了复合材料的传统机械加工、特种加工及其结构连接,其中特种加工主要介绍高压水射流、激光及超声波技术。     

基于水射流支撑的细长轴加工振动控制研究

振动严重影响细长轴的加工质量,由于细长轴类长径比大、刚性差,故很难控制其切削过程产生的振动.本文从振动的角度对细长轴切削时变形情况进行了分析,建立其振动的数学模型,并提出运用水射流辅助支撑来控制细长轴在切削过程中的振动.最后,对细长轴在有无水射流辅助支撑作用下进行了试验对比分析.结果表明,水射流辅助支撑可很好地控制细长轴加工振动,为提高细长轴的精度提供理论指导.     

超高压水切割机的现状与发展

在众多的切割手段中,只有水切割属于冷态切割,直接利用加磨料水射流的动能对金属进行切削而达到切割目的,切割过程中无化学变化,具有对切割材质理化性能无影响、无热变形、切缝窄、精度高、切面光洁、清洁无污染等优点,可加工传统加工及其它加工方法无法加工或难于加工的材料,如玻璃、陶瓷、复合材料、反光材料、化纤、热敏感材料等.     

磨料水射流切割的技术特征和工艺特征

分析了磨料水射流(AWJ)在难加工材料切割中切割断面、切缝和工艺参数影响等技术特征,提出从切割起点孔、直线段和曲线段的加工工艺改进来保证其切割质量。     

矩阵式数控加工在航空结构件批生产中的应用

以大批量数控加工的航空结构件生产为研究对象,运用人工干预环节集中化、数控加工过程自动化的理念,探索利用矩阵式数控加工进行多零件同时生产的应用方案。多零件集中装夹,通过系统自动读入每个零件的加工原点,自动调用零件的加工程序,完成相同(或不同)零件数控加工,在充分利用机床工作台面的同时,解决了批量生产过程中零件频繁装夹、找正、换刀和频繁调用加工程序的难题,达到降低劳动强度,提高生产效率的目的。     

喷射液束电解-激光复合加工工艺试验研究

喷射液束电解 激光复合加工是一项新探索的加工技术,其特点是既发挥激光加工的高效率,又借助喷射电液束的冷却、冲刷、电解作用而实现在线去除再铸层。基于该加工原理的分析,在对激光电解液中衰减特性研究的基础上,研制了试验系统并对不锈钢片进行了打孔工艺试验。试验结果表明,应用液压1.5 MPa、浓度18%的NaNO₃电解液的喷射液束电解-激光复合加工可实现再铸层减少90%以上。通过对打孔形貌的对比以及加工工艺规律的初步分析,揭示了喷射液束电解-激光复合加工以激光加工为主,电解加工辅助去除再铸层的加工原理,证实了该复合加工工艺的可行性,可望在航空航天领域得到广泛工程应用。     

Improving performance of macro electrolyte jet machining of TC4 titanium alloy: Experimental and numerical studies

Electrolyte jet machining (EJM) is a promising method for shaping titanium alloys due to its lack of tool wear, thermal and residual stress, and cracks and burrs. Recently, macro-EJM has attracted increasing attention for its high efficiency in machining wide grooves or planes. However, macro-EJM generates large amounts of electrolytic products, thereby increasing the difficulty of rapid product removal with a standard tool and reducing the surface quality. Therefore, for enhanced product transport, a novel tool with a back inclined end face was proposed for macro-EJM of TC4 titanium alloy. For comparison, also proposed were ones with a standard flat end face, a front inclined end face, and both front and back inclined end faces. The flow field distributions of all proposed tools were simulated numerically, and experiments were also conducted to validate the simulation results. The results show that one with a 5° back inclined end face can decrease the low-velocity flow zone in the machining area and increase the high-velocity flow zone at the back end of tool, thereby promoting rapid product removal. A relatively smooth bright-white groove surface was obtained. The same tool also resulted in the highest machining depth and material removal rate among the tested ones. In addition, rapid product removal was beneficial to the subsequent processing. Because of its rapid product removal, the machining depth and material removal rate during deep groove machining using the tool with a 5° back inclined end face were respectively 7% and 14% higher than those produced using a standard one. Moreover, the lowest bottom height difference of 0.027 mm can be obtained when the step-over value was 8.2 mm, and a plane with a depth of 0.285 mm and a bottom height difference of 0.03 mm was fabricated using the tool with a 5° back inclined end face.     

Surface-improvement mechanism of hybrid electrochemical discharge process using variable-amplitude pulses

Superalloys are commonly used in aircraft manufacturing; however, the requirements for high surface quality and machining accuracy make them difficult to machine. In this study, a hybrid electrochemical discharge process using variable-amplitude pulses is proposed to achieve this target. In this method, electrochemical machining (ECM) and electrical discharge machining (EDM) are unified into a single process using a sequence of variable-amplitude pulses such that the machining process realizes both good surface finish and high machining accuracy. Furthermore, the machining mechanism of the hybrid electrochemical discharge process using variable-amplitude pulses is studied. The mechanism is investigated by observations of machining waveforms and machined surface. It is found that, with a high-frequency transformation between high- and low-voltage waveforms within a voltage cycle, the machining mechanism is frequently transformed from EDM to pure ECM. The critical discharge voltage is 40 V. When pulse voltages greater than 40 V are applied, the machining accuracy is good; however, the surface has defects such as numerous discharge craters. High machining accuracy is maintained when high-voltage pulses are replaced by low-voltage pulses to enhance electrochemical dissolution. The results indicate that the proposed hybrid electrochemical discharge process using variable-amplitude pulses can yield high-quality surfaces with high machining accuracy.     

Electrochemical machining of complex components of aero-engines: Developments,trends, and technological advances

Because of several advantages, such as no tool wear, independence on the mechanical properties of the material, and high machining efficiency, electrochemical machining (ECM) has become a viable method for machining components in numerous industrial applications, particularly in the manufacture of typical aero-engine components with complex structures fabricated from materials that are difficult to cut. This paper highlights the current developments, new trends, and technological advances of key factors of ECM, such as electrochemical dissolution characteristics of novel difficult to cut materials which are often used in aero-engine, numerical simulation of electrochemical process, design for the complex profile and structure of cathode tool, flow field simulation and design for uniform electrolyte flow, and innovation of electrochemical machining or hybrid methods which reflect the state of the art in academic and industrial research on electrochemical machining in aero-engine manufacturing.     

现代特种加工技术的发展

简述了特种加工的技术特点和未来发展趋势,分别论述了高能束流加工、电火花加工、电解加工、物料切蚀加工和复合加工技术的概念、特征与应用状况。     

精密复杂曲面零件多轴数控加工技术研究进展

多轴数控（CNC）加工是现代工业中的标志性加工技术,在能源、动力、国防、运载工具、航空航天等制造领域的关键零部件加工中占据着主导地位。随着这些领域中高端装备性能要求越来越高,涌现出一大批加工难度大、性能指标要求苛刻的精密复杂曲面零件,其加工已由以往单纯的形位精度要求,跃升为形位与性能指标并重的高性能加工要求,给传统的复杂曲面零件数控加工技术带来了严峻挑战。针对精密复杂曲面零件形位精度保证、加工效率提升及动态切削过程可控等关键技术问题,从多轴数控加工的高效加工路径设计、进给率规划以及加工动力学分析等方面,详细论述相关加工技术的研究现状、存在的难点和核心问题,指出可行的解决途径、突破方向和未来的发展趋势,为实现复杂曲面零件的高性能数控加工提供参考和依据。     

制作微结构的超声复合加工机理

提出了制作微结构的超声复合加工方法,分析了超声、超声复合电火花、超声复合电解微细加工机理。用微细放电组合工艺制作了多种截形微细工具电极;完善试验系统,进行了多种材料、形状微结构超声复合加工试验。结果表明:超声加工是制作硬脆材料微结构的有效方法;超声复合电火花制作金属材料微结构有较好的精度及加工稳定性;超声复合电解加工兼有效率高、精度好的技术优势。     

表面状态及电解液对Ti6Al4V EJM加工质量的影响

钛合金广泛应用于航空发动机中,硝酸钠(Na NO3)电解液与氯化钠(Na Cl)电解液广泛应用于常规金属材料电化学加工。研究了钛合金在应用电解液喷射加工技术(EJM)时的表现。首先应用这两种电解液对两种不同表面质量的钛合金试件分别进行EJM加工试验,通过分析加工后所得样槽的深宽比、表面粗糙度、氧化物占比以及微观形貌,分析了钛合金原始表面状态以及电解液选用对最终加工精度的影响效果。在此基础上,以不同的顺序组合应用这两种电解液对优选出的钛合金试件再次进行EJM加工试验研究,确定最优的电解液组合应用顺序。两个系列的试验研究,为提高钛合金电化学喷射加工的质量与效率提供了一定的理论和试验依据。     

超细晶硬质合金加工机理及加工性能

围绕超细晶硬质合金精密磨削加工、在线电解修整磨削加工、电火花加工、超声复合加工、激光复合加工等加工方法,系统综述了超细晶硬质合金的加工机理和加工性能,并展望了超细晶硬质合金高效精密加工未来的研究重点。