Investigation of complex rapid EDM electrodes for rapid tooling applications

This paper describes a collaborative research programme aimed at investigating the use of quick EDM electrodes obtained via appropriate rapid prototyping techniques in finishing laser-sintered tools. Two methods were employed in obtaining the EDM electrodes: copper coating of stereolithography models and copper coating of direct metal laser sintered (bronze) models.The amount of copper deposited on both electrode models proved problematic as the electroplating process was unable to deposit enough copper in the inner cavities of the electrodes, with very gradual reduction in copper layer thickness from the outer faces/surface to virtually no deposition in the inner walls and bottom face. Consequently, the electrodes were not suitable for the envisaged EDM process.     

RP及RT技术的原理、方法和应用

从快速制造小批量产品样件和快速制造模具(以及模型和加工工具)方面,阐述了RP及RT技术在材料成形领域中的应用,内容涉及RP及RT技术的原理、方法和五种实用系统的工作过程和适用范围,以及快速原型制造技术在模具制造中的应用。     

Complex cast parts with rapid tooling: rapid manufacturing point of view

Rapid manufacturing techniques are typically either material addition or material subtraction processes. Direct metal laser sintering (DMLS) is a material addition process that enables the rapid creation of complex parts via laser sintering (or electron beam melting) whereby layers of powder are deposited and then partially or totally melted using a laser. This technique is directly challenging other more rapid, but subtractive manufacturing processes like high-speed milling (HSM) and electro-erosion. In terms of machining, the capacity of rapid tooling to quickly manufacture complex shapes, like conformal cooling channels, is an advantage (Boillat in J Phys IV 12(Pr 11):27–38, 2002, Au in Int J Adv Manuf Technol 34:496–515, 2007). On the other hand, the dimensional accuracy of this process is definitely lower than that obtained using HSM. To our knowledge, no systematic study of the dimensional capacities of this process has yet been carried out. In this article, through the geometrical study of the quality of the obtained parts, the capability of this process is studied and verified with respect to the required constraints of the die casting method.     

快速成形技术

快速成形技术是20世纪80年代末发展起来的一种集CAD/CAM、CNC、激光、新材料等技术于一体的现代先进制造技术,它可以自动、快速地将设计思想物化为具有一定结构和功能的原形或直接制造零部件,从而可以对产品设计进行快速评价、修改,以响应市场需求,提高企业的竞争力。快速成形技术的出现是适应日趋激烈的市场竞争的需要,对制造企业的模型、原型及成形件制造方式正产生深远的影响。1快速成形技术的基本原理快速成形技术的基本原理是基于“离散—堆积”的成形方法,借助三维CAD软件,或用实体反求方法采集得到有关原型或零件的几何形状、结…     

中国机床工业发展迅速

The 2,404 enterprises in the eight sectors of China＇s machine tool industry generated a total industrial output value amounting to RMB 165.611 billion in 2006, an increase of 27.1%, and 2.3 percentage points higher than the growth of the previous year, according to the National Bureau of Statistics. Their total sales topped RMB 158.613 billion, jumping 26.4%; and the total profits, RMB 9,350.59 million, up 32.4%.     

HBA-101型化学需氧量快速分析仪的研制

研制了HBA-101型化学需氧量快速分析仪.仪器由20孔恒温消解器、专用比色计(含自动采样和清洗系统及单片机数据处理系统)组成,具有批量消解、快速测定的特点,方法符合国家关于CODCr标准分析方法的要求.线性方程为A=0.00078C 0.00118,相关系数为r=0.9999,RSD=2.8%.样品测定结果与标准方法具有良好的一致性.     

Software compensation of rapid prototyping machines

This paper addresses accuracy improvement of rapid prototyping (RP) machines by parametric error modeling and software error compensation. This approach is inspired by the techniques developed over the years for the parametric evaluation of coordinate measuring machines (CMM) and machine tool systems. The confounded effects of all errors in a RP machine are mapped into a “virtual” parametric machine error model. A generic artifact is built on the RP machine and measured by a master CMM. Measurement results are then used to develop a machine error function and error compensation is applied to the files which drive the build tool. The method is applied to three test parts and the results show a significant improvement in dimensional accuracy of built parts.     

基于AutoCAD快速绘图方法的研究

AutoCAD是目前国际上流行的绘图软件,以其强大的数据处理功能,广泛应用于机械、建筑、航天等领域.本研究寻求提高绘图效率的方法.实践显示,文中所介绍的创建国家标准模板、尺寸标注等方法,通过修改系统函数库中的常用变量和参数设置,利用AutoCAD自带的开发功能进行线型开发,在使用过程中只需调入函数名称.特别是利用其二次开发工具Auto LISP语言在AutoCAD平台进行的二次开发,可实现参数化绘图程序设计.用户可自行通过定义带有属性的块的方法,开发表面粗糙度等工程符号,使用时只需按照提示输入所需要的数值和要求即可.综合上述研究结果,在具体绘图过程中使用起来方便、简洁、实用、高效、快速,为设计者节省了大量时间,达到在短时间内绘图、审核、修改的目的.     

快速原型技术研究综述

在研究快速原型技术发展历史和现状的基础上，介绍了快速原型制造的基本原理，重点介绍几种发展较成熟的RP技术的基本原理，分析RP技术的特点，并探讨其应用价值和发展前景，提出了目前发展快速成型的基本观点和未来发展趋势。     

基于层合速凝技术的陶瓷件快速成型研究

结合快速原型制造技术的原理提出了一种新的陶瓷制件快速成型技术,即层合速凝快速成型技术.该技术特别适用于复杂陶瓷制件的快速制造,具有高效率、高精度、低成本等特点.主要介绍了层合速凝快速成型技术的原理和应用于陶瓷制件的研究现状,比较分析了该技术三种不同工艺的优缺点,并对该技术今后的发展作了展望.     

Application of rapid prototyping and rapid tooling for development of patient-specific craniofacial implant: an investigative study

In today’s competitive world, the life-style of the average human being has become very fast. This causes a huge number traffic accidents resulting in various types of injuries. In India, most of these accidents take place during bike riding and this causes different types of fracture of bones. One of these injuries is head injury. For the proper treatment of such patients, demands for patient-specific craniofacial bio-implants are increasing day by day. This kind of ‘tailored’ implant development through near net shape manufacturing is a highly challenging task since the developmental time and cost has to be as low as possible. At the Central Mechanical Engineering Research Institute (CMERI), one such process of implant development was explored taking one case of head injury. The implant was developed through the “3D CAD-rapid prototyping (RP)-rapid tooling (RT)-investment casting (IC)” route. For achieving the task, only the facilities available at CMERI were utilized.     

便携式MicroRNA快速检测系统

MicroRNA(miRNA)与疾病的发生和发展密切相关,可作为疾病诊断标志物。常规检测miRNA的方法耗时较长且操作复杂,本文设计了一种便携式miRNA快速检测系统。该系统采用光电检测技术检测滚环扩增后的标志物miRNA受激发出的荧光强度,对采集到的荧光数据进行分析,得出miRNA的变化情况。实验得出便携式miRNA快速检测系统在试剂浓度为0.1~1μmol时,荧光强度线性偏倚不超过±5%,系统重复性大于95%。通过对冠心病检测标志物miR-499进行滚环扩增实验,结果表明设计的便携式miRNA快速检测系统能够快速有效地检测miRNA。     

面向客户的产品快速设计

简要阐述了自动推断优化工程设计技术(WAVE),提出了基于WAVE面向客户的产品快速设计方法,以BL系列车床为例详细介绍了这种技术与产品设计过程的融合,在了解BL系列车床产品设计特点和客户设计需求的基础上,总结并提炼出用于控制车床设计的工程技术参数,通过建立产品控制结构,实现了面向客户的BL系列车床快速设计,实例表明这里所提出的方法是有效的。     

NMOHEMS探测单元的三维建模与快速成型

探测单元是新型远海机动水文环境监测系统(NMOHEMS)的关键部件,用于探测温度、水深、盐度等水文要素,其内部搭载的水文要素传感器探头是获取各水文要素的最终执行者,与陆地作业探测仪器相比,其机械结构、控制系统更复杂。为完成探测单元模型制作、运动仿真及水上试验,在前期完成的探测单元结构设计基础上,借助Inventor软件快速建立探测单元零部件三维实体模型,并利用三维快速成型技术完成模型初样制作。制作初样表明:基于三维零件模型的成形工艺,大大缩短研发周期,增强了设计的可信度。     

大型零件光固化快速成型工艺研究

光固化原型制作过程中存在的主要问题是变形和表面台阶效应.为此,基于零件光固化成型的变形规律,分析了零件的层片截面类型及其变形特性.针对零件制作的变形问题,从制作方向、支撑结构和抗变形辅助结构3个方面研究了抗变形工艺,并据此研究了大型零件的分割拼合技术.最后,通过制作实例的分析,验证了大型零件分割制作和拼合技术的可行性.     

带式输送机托辊快速更换技术

1引言 天津港是我国北方重要的煤炭输出大港,专业化输送系统的广泛应用,为天津港生产任务连续实现跨越式发展提供了可靠的设备保障,同时,也给设备管理提出了新的研究课题。2007年公司带式输送机系统故障统计见表1。     

基于速成型技术的模具制造

介绍了目前主要的快速成型方法,及其原理和特征.并分析了各种成型方法的优缺点,与传统快速制模技术相结合,形成新产品小批量、多品种的快速制造.最后对所存在的问题进行了分析和研究提出一些建议.     

滚动轴承分组快速试验方法

针对滚动轴承疲劳寿命试验周期长、消耗大量人力物力的情况,经过试验证明,采取分组试验方法可以在保证试验数据准确的情况下有效地缩短试验周期。     

数控选区电化学沉积快速成型技术研究

基于快速成型及电化学沉积原理,提出了数控选区电化学沉积快速成型制造技术,研制了该系统并进行了基础试验研究,并采用该方法及系统制备了简单形状的铜零件.研究表明,样件具有良好的形状精度、尺寸精度及致密组织.大大提高了电流密度和沉积速度,并克服了传统电铸技术必须依赖母模的缺陷,拓宽了快速成型及电铸技术的应用领域.