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.     

A novel arc-spraying robot for rapid tooling

In order to reduce the process uncertainty and the labor intensity in manual metal arc spraying for rapid tooling, this paper presents a robot wrist design and a robot motion control method based on the cross-sectional contours and related surface normal vectors extracted from STL model, a de facto standard for representing a 3D part geometry in rapid prototyping (RP) industry. A computer controlled five-axis robot for the rapid tooling was built by using the wrist, which drives the spraying gun. The wrist comprises a linkage that can maintain the working position of the gun while changing its spraying orientation freely. Such a design ensures that adjusting the gun along the normal of the master surface to satisfy the process requirement will not result in any position change of the spraying point. A kinematic analysis on the wrist indicates this kinematic decoupling between the positioning mechanism and the orientating mechanism. The working trajectory of the gun is generated off-line by slicing the STL model of the master pattern. To bypass the need for any teaching or NC programming, the arc-spraying robot can carry out the tooling process automatically and efficiently fully based on the sliced data of the master pattern. In addition, a case study on the production of automobile body panel dies using this robotic tooling system is introduced.     

Solid ideas [rapid prototyping]

Rapid prototyping is fast becoming one of the essential technologies that allows manufacturers to improve product quality and reduce both time to market and the cost of new lines, as part of a concurrent engineering strategy. RP technologies can be virtual (soft/CAD-based) or physical (hard). Physical RP allows designers to build tangible models of their designs quickly and cheaply. This encourages experimentation, and flags errors in the fit or assembly of the part. This article looks at the existing physical rapid prototyping technologies     

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。     

快速模具系统工艺特点与分析

采用传统的模具加工方法,制造周期长且成本高。快速成型配合传统制模技术不仅适合单件小批的模具快速制造,而且能适应各种复杂程度的模具快速制造。介绍了基于快速成型技术的快速模具制造技术工艺原理、分类、成型方法及其技术特点以及与传统成形方式的区别。从模具的寿命,模具的制作成本,模具的生产周期等方面对几种典型快速模具制造技术系统进行了比较和归纳。分析了快速模具制造技术面临的关键问题,展望了基于快速成型原理的快速模具制造的应用前景。     

搅拌车搅拌叶片快速模具制造

混凝土搅拌车的搅拌叶片,是一种比较复杂的空间曲面,制造起来比较困难.传统的模具制造成本较高,不适用于新产品的开发和实验研究.提出一种快速的叶片模具制造方法,通过UG软件对叶片进行参数化设计,然后对叶片分段切割,计算截面坐标,再按坐标值切割钢板后焊接成模具,压制出叶片.该方法制造方便,成本低廉,特别适用于实验研究场合叶片的制作.     

基于ERP的快速模具制造系统设计

阐述了ERP系统的管理思想和快速原型技术在模具制造中的应用，提出在ERP系统中实施快速模具制造的组织模式。     

Feasibility study of a new rapid tooling process

The requirements for faster product development cycles, lower product cost and environmental sustainability are ever increasing in today’s globally competitive market. Tooling is a very important phase in the product manufacturing cycle. To overcome the shortcomings of long lead-time and high cost associated with conventional tooling processes, new tooling methods with shorter lead-time and lower cost are strongly under demand. In this study, the feasibility of the proposed new rapid tooling process based on back support of a metal shell with packed metal powders is examined. First, the effect of metal powder properties, such as powder shape, size, and size distributions, on powder-packing behaviour is investigated experimentally. Then, the compressive behaviours of the metal shell and the shell-powder assembly are analysed numerically with different compressive loading. The study indicates that the proposed new rapid tooling method can potentially be used for injection moulding applications.     

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.     

基于RPM快速制模技术的发展

介绍快速原型制造技术在快速模具制造应用中的原理、直接及问接制模的技术方法和快速制模的新发展。     

快速原型直接模具在熔模铸造中的应用研究

针对单件小批量产品的熔模铸造,提出了快速原型方法直接烧结模具,并用该模具浇制低温合金熔模的方法.提供了较为详细的解决问题的步骤,并作了相应的分析和论证.此直接模具制造并浇制熔模的方案,简单易行,可使生产周期大大缩短,有利于产品迅速响应市场需求.     

Tribological behaviour of epoxy based composites for rapid tooling

Epoxy resin composites are frequently applied in moulds manufactured with rapid tooling technologies that are used for wax and polymer materials injection. With the propose of enlarging the application field of the polymer matrix systems, it is fundamental to select adequate dispersed phases and analyse their influence on the composite properties in order to reinforce the polymer matrix and tailor the properties according to the tools specifications.Thermal conductivity and wear resistance are critical parameters for a good service performance and durability of the mould. Metallic fillers allow significant improvement in the resin thermal conductivity. In this work, it was possible to show that small amounts of milled fibres enhance the wear resistance, with little changes in the processability and in the allowed aluminium concentration in the resin matrix.A tribological study of these materials was performed involving the neat resin, the aluminium filled resin and tri-phase composites composed by epoxy, aluminium particles and milled glass or carbon fibres. The study was focused on the role of the particles and fibres in the friction and wear at room temperature and at a typical plastic injection temperature of 160 °C.     

Modelling for all occasions [rapid prototyping]

Rapid prototyping can dramatically cut the time taken to get a new product to market, and can even be used to create tools and products directly. In the second of two articles, D.T. Pham and R.S. Gault examine the strengths and weaknesses of the various technologies and give advice on how to choose a system for your needs     

Integrating rapid prototyping and tooling with vacuum casting for connectors

Connectors are developed to satisfy the needs of advanced technology in telecommunication switching systems and companies have several products designed to fulfil the needs of the many switching networks available. The Four-wall-header is one such product from one company. The traditional manufacturing line relies heavily on hard tooling which is both expensive and time-consuming. This paper presents an alternative method of integrating rapid prototyping technologies, in particular, stereolithography apparatus (SLA), with a vacuum casting system to produce a wide range of polyurethane parts. Altogether, three approaches are analysed and evaluated for making the moulds: rapid pattern, rapid tooling and a hybrid approach.     

面向等离子熔射快速制模可视化系统的三维形状检测技术

提高金属原型等离子熔积成形的精度是使该技术走向实用化的关键之一。本文将傅立叶变换轮廓法用于等离子熔积成形过程中零件的三维形状检测，来对模型的尺寸和成形过程工艺参数进行修正和补偿，提高成形精度。文章详细论述了该方法的测量原理、零件形状与所求得的相位之间的关系，建立了三雏形状测量的系统构架，最后给出了测量结果并提出了误差来源和改进措施。     

基于知识和模块化的工装快速设计研究

多品种、小批量、变状态的离散航空企业,其工装的经济性和研制周期都已无法满足目前敏捷制造和精益生产的需求,另外设计经验和知识也无法得到重用和继承。针对企业目前存在的问题,提出了以成组技术、知识工程和标准化模块化思想为指导的工装快速设计研究。以三维设计软件CATIA为平台、以参数化建模的工装知识库为基础,实现了基于B/S和C/S的工装快速设计系统的高度集成。通过知识管理、免编程的知识推理设计和工装的模块化设计为手段,实现了工装的快速设计,大幅度提升了工装设计效率和质量,降低了工装制造和管理成本。     

面向航空发动机工装快速设计系统的信息模型研究

针对航空发动机工装设计过程及企业开发工装快速设计系统的需求,本文旨在研究并开发一个包含航空发动机一系列工装设计信息的信息模型,其中包括:零部件的几何拓扑信息、零部件间的约束信息以及零件的载荷信息,同时,设计了一套基于信息功能特征的编码方法.该信息模型已应用于自主开发的航空发动机工装快速设计系统中.     

Plaster casting process for prototyping of die casting based on rapid tooling

Rapid prototyping (RP) combined with a gravity casting process can provide a suitable substitute with steel tool die casting for prototyping metal casting. Due to differences between die casting and gravity casting, there are several drawbacks in RP simulated die casting. This paper is concerned with the development of a new plaster die casting process that combines pressurization and vibration for prototyping of die castings, and with a plaster die casting machine that has a structure similar to that of a die casting machine. The machine utilizes an oil cylinder for pressurization and a magnetic actuator for vibration. A rapid prototyped pattern is made by the laminated object manufacturing (LOM) process to prepare a plaster mold. In the process, a plunger in the developed machine simultaneously pressurizes and vibrates the molten metal to fill the plaster mold completely and to facilitate the creation of nuclei in the molten metal, respectively. The developed machine has produced a prototype of an end clutch cover with remarkable improvement in mechanical properties.