一机多枪氩弧自动点焊机的研制

介绍由一台直流焊枪,多把焊枪及氩弧自动焊控制器组成的自动点焊机,该焊机自动进行各把焊枪的引弧－焊接－熄弧以及焊枪间顺序转换,对结构复杂的构件实现多点全位置氩弧占焊,与制作较复杂的转台夹具来转动构件或制造高精度机械手械手焊枪转动实现氩弧点焊相比,其制造成本低,容易实现。     

Reactive atom plasma (RAP) figuring machine for meter class optical surfaces

A new surface figuring machine called Helios 1200 is presented in this paper. It is designed for the figuring of meter sized optical surfaces with form accuracy correction capability better than 20 nm rms within a reduced number of iterations. Unlike other large figuring facilities using energy beams, Helios 1200 operates a plasma torch at atmospheric pressure, offers a high material removal rate, and a relatively low running cost. This facility is ideal to process large optical components, lightweight optics, silicon based and difficult to machine materials, aspheric, and free form surfaces. Also, the surfaces processed by the reactive atom plasma (RAP) are easy to fine polish through hand conventional sub-aperture polishing techniques. These unique combined features lead to a new capability for the fabrication of optical components opening up novel design possibilities for optical engineers. The key technical features of this large RAP machine are fast figuring capabilities, non-contact material removal tool, the use of a near Gaussian footprint energy beam, and a proven tool path strategy for the management of the heat transfer. Helios 1200 complies with the European machine safety standard and can be used with different types of reactive gases using either fluorine or chlorine compounds. In this paper, first the need for large optical component is discussed. Then, the RAP facility is described: radio frequency R.F generator, plasma torch, and 3 axis computer numerically controlled motion system. Both the machine design and the performance of the RAP tool is assessed under specific production conditions and in the context of meter class mirror and lens fabrication.     

A multiprocess machine tool for compound micromachining

Compound micromachining is the most promising technology for the production of miniaturized parts and this technology is becoming increasingly more important and popular because of a growing demand for industrial products, with an increased number not only of functions but also of reduced dimensions, higher dimensional accuracy and better surface finish. Compound micromachining processes that combine multiple conventional and non-conventional micromachining processes have the capability to fabricate high aspect ratio microstructures with paramount dimensional accuracy. Such machining should be carried out on the same machine with minimum change of setups. At the same time, on-machine tool fabrication along with on-machine tool and workpiece measurement facilities should also be available for further enhancement of the functionality of the machine and higher productivity. In order to achieve effective implementation of compound micromachining techniques, this research seeks to address four important areas, namely (a) development of a machine tool capable of both conventional micromachining including microturning, micromilling, etc., and non-conventional micromachining including microelectrical discharge machining (micro-EDM), wire-cut electrical discharge machining (WEDM), etc.; (b) process control; (c) process development to achieve the necessary accuracy and quality and (d) on-machine measurement and inspection. An integrated effort into these areas has resulted in successful fabrication of microstructures that are able to meet the miniaturization demands of the industry. This paper presents a few tool-based approaches that integrate micro-EDM, micro-EDG, microturning and microgrinding to produce miniature components on the same machine tool platform in order to demonstrate the capabilities of compound micromachining.     

高精密小型动压悬浮自动流延机的设计

电子陶瓷薄膜是片式电子元器件制造和大规模集成电路封装的关键薄膜材料，它是在高精密流延机上利用电子陶瓷浆料流延获得的。因此，如何设计与制造高精密自动流延机是保证流延膜的生产质量与效率的关键。文章提出了一种基于非牛顿液体动压悬浮理论的高精密陶瓷薄膜流延方法，并设计了小型全自动流延机。对小型流延机的系统构成、成膜原理、流延膜的传输运动、干燥原理、浆料的供给和系统的控制，以及它们的机械实现等问题进行了分析和探讨。     

集束电极的CAD/CAM软件开发及制备

集束电极由大量棒状或管状单元集束而成,其多孔结构可在电火花加工过程中实现多孔内冲液以改善极间放电状态。针对集束电极的结构特点,基于UG开发了集束电极快速制备CAM软件,该软件可根据目标实体模型生成制备集束电极的数控代码,结合设计的集束电极制备装置,实现集束电极的快速、低成本制备。     

光固化成形基于切片轮廓信息的变方向路径算法研究

光固化成形是一种基于逐层累加方式发展起来的新的制作工艺,零件的加工效率是成形中需要考虑的关键问题之一.激光扫描路径和扫描速度影响每层加工时间.扫描速度一定时,扫描路径的优化与否将直接影响加工时间.本文对平行扫描路径进行分析,针对激光器扫描时加减速额外消耗时间,运用图形学中多边形性质及激光扫描过程特点,提出了优化扫描方向的算法,可在不降低精度的基础上大幅度提高效率.文章给出了这种扫描路径的轨迹生成方案,并提出提取狭长分枝的分区算法.     

Analysis of thermal errors in a high-speed micro-milling spindle

Thermally induced errors account for the majority of fabrication accuracy loss in an uncompensated machine tool. This issue is particularly relevant in the micro-machining arena due to the comparable size of thermal errors and the characteristic dimensions of the parts under fabrication. A spindle of a micro-milling machine tool is one of the main sources of thermal errors. Other sources of thermal errors include drive elements like linear motors and bearings, the machining process itself and external thermal influences such as variation in ambient temperature. The basic strategy for alleviating the magnitude of these thermal errors can be achieved by thermal desensitization, control and compensation within the machine tool.This paper describes a spindle growth compensation scheme that aims towards reducing its thermally-induced machining errors. The implementation of this scheme is simple in nature and it can be easily and quickly executed in an industrial environment with minimal investment of manpower and component modifications.Initially a finite element analysis (FEA) is conducted on the spindle assembly. This FEA correlates the temperature rise, due to heating from the spindle bearings and the motor, to the resulting structural deformation. Additionally, the structural deformation of the spindle along with temperature change at its various critical points is experimentally obtained by a system of thermocouples and capacitance gages.The experimental values of the temperature changes and the structural deformation of the spindle qualitatively agree well with the results obtained by FEA. Consequently, a thermal displacement model of the high-speed micro-milling spindle is formulated from the previously obtained experimental results that effectively predict the spindle displacement under varying spindle speeds. The implementation of this model in the machine tool under investigation is expected to reduce its thermally induced spindle displacement by 80%, from 6 microns to less than 1 micron in a randomly generated test with varying spindle speeds.     

Development of ultra-precision machining system with unique wire EDM tool fabrication system for micro/nano-machining

Aiming at quality machining of very hard materials with nanometer level surface quality and 0.1 μm dimensional accuracy, an ultra-precision machining system has been developed. The machine has feed axes accompanied by the counter motion mechanism driven at the center of gravity to eliminate the vibration caused by high acceleration/deceleration. A custom tool fabrication system consists of a 6-axis wire EDM machine and dedicated custom tool CAM system. High quality machining of sophisticated three-dimensional (3D) products made of tungsten carbide has successfully been demonstrated on the developed machine tool with custom-made PCD cutters fabricated by the tool fabrication system.     

Development and evaluation of ferrocement legs for a lathe

The feasibility of using ferrocement as a replacement material for cast iron in the fabrication of supporting legs (columns) for a centre lathe has been investigated in this project. These machine tool structures were designed with the aid of a finite element package so as to have static stiffnesses at least equal to those of the corresponding cast iron legs. Tests were carried out to evaluate the performance of the ferrocement legs with reference to the traditional cast iron legs. The highly improved dynamic performance as exhibited by the ferrocement legs indicates that this new construction materials has a great potential in the machine tool industry.     

EDM石墨电极的快速研磨制造

介绍了一种电火花加工用石墨电极的整体制造技术，这种技术采用Hausermann研磨原理，通过将快速成型技术制成的母型翻制成研具，实现对石墨电极的研磨加工；介绍了研具的具体制造方法和研磨成型机的主要菇构。以某型号拖拉机连杆的精锻模具电火花加工为例，介绍了连杆的三维CAD造型和快速成型制造、碳化硅研具的翻制、整体石墨电极的研磨加工和模具的电火花加工。     

容器接管马鞍形焊缝埋弧自动焊设备与工艺的研究

容器接管马鞍形焊缝的焊接,国内过去都采用手工焊,工作量大、效率低、劳动条件差、质量不易保证、返修率高。针对容器正交插入式接管管座的焊接,研制了MZM—500型马鞍形埋弧焊机,拟定了自动焊工艺,并成功地进行了400T/h 电站锅炉汽包下降管管座的自动焊生产。MZM—500型焊机适用于简身直径≥1400mm,接管外径=420～820mm,内径≥320mm,接管高度=200～500mm 的马鞍形焊缝的焊接。容器接管马鞍形焊缝的埋弧自动焊,与手工焊相比,可提高生产率1～2倍,降低了工件预热温度,改善了劳动条件,焊缝质量也易于保证.     

微小齿轮模具的微细电火花线切割加工研究

介绍了微细电火花线切割加工微小齿轮模具的方法，其关键技术包括：晶体管可控微能量RC脉冲电源、间隙放电状态检测系统、基于压电陶瓷电机驱动的精密伺服机构和偏开路加工控制策略。使用微细电火花线切割加工机可一次切割出厚度为1mm、模数为0．04和厚度为3、5mm、模数为0．1的微小齿轮模具，表明由微细电火花线切割加工出的微小齿轮模具能满足微成形加工的技术要求。     

先进的模具加工设备与技术简介

介绍某厂近期引进的三套先进的模具加工、检测装备与技术：模具喷砂清理机，模具三维检测仪,模具加工中心.     

Compound scan mode developed from subarea and contour scan mode for selective laser sintering

Scan mode is an important parameter for selective laser sintering (SLS) processing. The improved mode will optimize scan path and improve the precision, strength and fabrication efficiency of a SLS part. A compound scan mode, which combines subarea scan mode and contour scan mode, is proposed. The principle of its hatch (path-planning) algorithm and implementation are presented. To testify the effectiveness of this compound mode compared to that of subarea scan mode, it has been utilized for researches at a SLS machine developed at Huangzhong University of Science and Technique (HUST). The results from the researches indicate that the degree of precision of a SLS part with the compound scan mode is higher than that with subarea one. There is little difference in the tensile strength, flexural strength, shock strength and fabrication efficiency of a SLS part under the compound scan pattern and the subarea scan mode. Therefore, implementation of the compound scan mode is of importance to improve the precision of a SLS part.     

Improvement strategy for machine tool vibration induced from the movement of a counterweight during machining process

The objective of this study is to propose and execute an improvement strategy for machine tool vibration induced from the movement of a counterweight balance system during the machining process. The elastic jump due to the effects of the inertia of a counterweight and of the potential energy released from the connected chain is investigated, firstly by using the dynamic analysis numerical software, Nastran, when the machine tool head makes a sudden stop during different motion types in the machining process. In turn, the vibration energy absorber, such as spring and damper, is assembled together in parallel manner, which is then connected to the counterweight in series, attempting to reduce the phenomenon of induced vibration to the utmost. The design and fabrication of a vibration reduction system for machine tool head during the machining process is performed based on the absorber parameters obtained from the simulation calculations. Milling experiment on aluminum alloy is undertaken in conjunction with various CNC cutting-path planning, such as moderate steps and vertical steps under different feed-rate cutting conditions. No concentric-strip-like waviness was detected on machined surface during the former cutting path. But such kinds of waviness marks left on the machined surface around the corner area between the subsequent steps are very obvious with the vertical-step path. This induced tool vibration phenomenon is remarkably improved through the strategies proposed and implemented in this study.     

GLJ-1型自行车架管连接自动焊机

介绍了一种 新型的自行车架管连接自动焊机的结构，组成和工作原理，生产实践证明该焊机在自行车架的自动焊接生产中取得了良好效果，是一种低成本自动化的管理连接相贯线焊缝专用焊接设备。     

基于微细电火花加工的微冲切实验研究

针对复杂异型截面微冲切模具加工中凸模难以制备的问题,利用微细电火花三维铣削技术与电火花反拷贝加工技术相结合进行整套微冲切模具的在线制备,解决了复杂异型截面微冲切模具的制备及凹凸模具的对中等问题。采用该复合加工方案进行了微冲切凹凸模具的在线制备和微冲切加工实验,成功制备出精度、质量较好的复杂异形截面微模具及异形孔,并对冲裁件局部特征进行了详细分析,验证了该方案的可行性。     

A study on the machining of high-aspect ratio micro-structures using micro-EDM

Micro-electro-discharge machining (micro-EDM or μ-EDM) has been gaining popularity as a new alternative method to fabricate micro-structures. The main advantages of the micro-EDM method are its low set-up cost, high accuracy and large design freedom. Compared to etching or deposition techniques, micro-EDM has the advantage of being able to fabricate complex three-dimensional shapes with high-aspect ratio. However, there are many operating parameters that affect the micro-EDM process. The fabrication of micro-electrodes on the machine is also an important process to remove the clamping error to maintain high accuracy in the machined micro-structures.

In this paper, the machining of micro-structures is divided into two basic processes. One is the on-machine fabrication of the micro-electrodes with high-aspect ratio, and the other is the EDM of the workpiece in micrometer range. An optical sensor has been developed to measure and control the dimension of the thin electrode during the tool fabrication process. Different methods have been investigated to fabricate a thin electrode into the desired dimension without deflection. The performance of the micro-EDM process is evaluated in terms of the material removal rate (MRR), tool wear ratio (TWR), and the stability of the machining. Influences of the various operating parameters of the micro-EDM process, such as the operating voltage, gap control algorithm, and resistance and capacitance values in the R–C spark control circuit, are discussed.     

建筑制瓦一体机的设计与关键结构分析

基于现有制瓦设备机械一体化程度不高以及关键结构稳定性方面存在的问题，以一款新型的建筑制瓦一体机为研究对象，确定其结构参数设计中的主要问题，利用数学模型对关键结构进行物理特性分析，在此基础上依据可靠性干涉原理对各关键结构进行稳定性分析。分析结果证明这款新型建筑制瓦一体机结构的合理性，并通过实验确定其可靠性。该研究方法可为建筑制瓦设备关键零件的精益设计提供参考。     

数控小孔冲床网眼平板加工中的波浪纹缺陷成因分析及排除

文章就数控小孔冲床加工纺织烘干设备中帘子网眼平板产生波浪纹缺陷的原因,进行了全面、详细的理论分析.在排除机床、模具精度影响的基础上,针对压料机构运动误差产生的机理和不利影响,详细分析了网眼冲孔加工产生波浪纹缺陷的根本原因,提出了相应的改进措施,在实践中具有良好的实用效果.