虚拟产品开发中的虚拟样机技术和数字样机技术

文章就虚拟产品开发,虚拟样机技术和数字样机技术产生的历史背景、特点、三者的关系以及在现代化机械制造业中的作用进行阐述。     

An algorithm for disintegrating large and complex rapid prototyping objects in a CAD environment

A CAD application tool kit interfacing with a Unigraphics (UG) system was developed for disintegrating large and complex rapid prototyping objects into smaller and simpler components which can be fabricated by a rapid prototyping system. As the core of the tool kit, the algorithm of such disintegration is described in detail in this paper. The algorithm combines the flat planar parting method and feature-based volume decomposition. Due consideration is also given to the optimisation of the surface accuracy, the build time, and the strength and number of segments generated. Based on the algorithm and the CAD application tool kit, the disintegration of two RP objects was realised in a selective laser sintering system.     

Adaptive direct slicing of a commercial CAD model for use in rapid prototyping

Slicing a 3D graphic model into layers of 2D contour plots is an essential step for all rapid prototyping (RP) machines. Various methods are available, such as stereo lithography (STL) file slicing, direct slicing and adaptive direct slicing. Amongst these, adaptive direct slicing is the most advanced for its capability of adapting the slicing thickness according to the curvature of any contour. In this study, an adaptive direct slicing method complete with the algorithm for calculating the thickness of each layer is proposed. As an illustration of the method, the algorithm was programmed within the commercial CAD software package, PowerSHAPE. The method was shown to be fast and accurate in comparison with STL file slicing and direct slicing, which both used a constant layer thickness. An erratum to this article can be found at     

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.     

快速成形技术的研究热点及其展望

介绍了快速成形技术的特点和生产过程,指出快速成形技术的研究热点是研究新的成形设备应用软件、扩充现有成形技术的应用领域、探索新的成形工艺和开发新型材料等几个方面,展望了快速成形技术在未来的发展趋势。     

SLM激光快速成型设备的设计与开发

选择性激光熔化(SLM)技术是目前较先进的激光快速成型技术,而高精度的SLM设备是进行SLM快速成型研究的基础.由于进口设备价格昂贵,所以自主开发了一套SLM设备.论述了该设备的设计和制造要求、总体结构和工作原理及主要组成部分的性能特点和功能.给出了加工实例.该设备具有成本较低、运行平稳、加工精度高等特点,为同类设备的研发提供了借鉴.     

快速成型技术在智能电动天窗零部件研制中的应用

结合某企业研发的汽车智能电动天窗机构零件的试制,介绍了试制的汽车智能电动天窗机构的主要零部件之间的作用及其制造工艺过程,并就天窗机构中导水槽托架零件的研制,从零件的三维数字模型的建立,模型数据的处理和最终实现实体模型三维打印等快速成型制造工艺过程进行了较为详细的分析,指出了快速成型制造技术在产品零件小批量试制中,具有成...     

选区激光烧结(SLS)快速成型中CAD模型的工艺性研究

研究分析选区激光烧结 (SLS)快速成型中 ,不同尺寸和形状零件的CAD模型建立时的工艺性 ,根据实际经验得出了一些解决问题的方法     

An integrated experimental approach to link a laser digitiser, a CAD/CAM system and a rapid prototyping system for biomedical applications

This study is carried out to develop a direct link between a laser digitiser and a rapid prototyping system for biomedical applications. Two CAD/CAM systems, DUCT and Pro-Engineer, are investigated and the DUCT system is found to be more suitable for this purpose. A laser digitiser is used to capture three-dimensional surface data for the object. With the aid of the CAD/CAM system, the data can be manipulated in a number of ways for display, modification and enhancement. In addition, the object scanned by the laser digitiser can be physically produced relatively quickly and accurately using StereoLithography Apparatus (SLA), a leading rapid prototyping system. Feasible and practical solutions to the problems encountered in the CAD surface model construction are proposed and illustrated. Two case studies, a facial and a breast model, are presented. Results show that this integrated approach can be applied effectively in the biomedical field.     

基于创新的机械产品快速响应设计/制造的关键技术及其应用研究

针对机械产品,首先介绍新产品开发中计算机辅助创新技术;而后阐述针对用户需求的快速响应关键技术,包括计算机辅助模块化技术,基于FEM的变量化结构快速优化技术,基于知识工程（KBE）的特定产品快速开发系统构建,基于CAX的快速设计／制造系统的集成,以及特定机械产品快速设计／制造软件系统的开发工具研究。最后以实例来介绍此技术的应用状况,以此来阐述产品快速设计／制造技术开发的可行性、必要性及其模式。     

Qualification of rapid prototyping tools: proposition of a procedure and a test part

Rapid prototyping machines are becoming faster at manufacturing machine tools. The processes of quality assurance impose the qualification of the production devices. A procedure and a test part are proposed for that purpose; intended for the family of processes of point-by-point layer manufacturing. Existing test parts only permit benchmarking and comparisons between machines: their capacity can be evaluated, but the test part analysis does not make it possible to establish the link between noted defects and their causes. The proposed process and test part permit the identification of the defects and whether their origins are machine or material linked. This paper describes the approach used to design the test part. Some preliminary measures were made on a test part, in order to discuss procedure and measurements.     

An asynchronous and synchronous coupling approach in networked rapid product development

Faced with today's competitive market, the development of innovative product needs to be accelerated. But this is limited by heterogeneous systems and a distributed environment. A way of utilising network technology to this end must be found. In this paper, we use a new approach, called asynchronous and synchronous coupling, which is a network-based product development approach. This is then applied to rapid-response manufacturing by small- and medium-sized enterprises in a distributed environment. It demonstrates integrated thinking, high development speed and a transparent development process. Visual technology and real-time monitoring technology are used to solve asynchronous process and data management problems. An ICE (integrated collaborative environment) is also created to support synchronous collaboration.     

Re-triangulation in STL meshes for rapid prototyping and manufacture

The main objective of this research is to identify ways to simplify the STL meshes, while simultaneously maintaining the accuracy of the STL file. It demonstrates a technique to simplify large and complex STL triangular meshes and to optimise STL shape for rapid prototyping and manufacture. STL mesh re-triangulation can be separated into two processes, i.e., mesh deletion and mesh rearrangement. In the mesh deletion process, two kinds of weighted-value ratio algorithms can be chosen for determining the suitable value of STL mesh deletion. A genetic algorithm that incorporated fitness functions was used for the optimisation of the rearranged STL meshes. Two case studies of STL mesh reconstruction, which examine the effects of the algorithms, are presented. These studies show that optimisation of the shape of the STL file reduces its size, resulting in a reduction of the fabrication time and improvement of the rapid prototyping process.     

快速原型技术及其在RT中的应用

介绍快速原型技术（RP）的发展史,快速原型技术常用的几种成型工艺方法,快速原型技术（RP）在快速制模技术（RT）中的应用及所取得的明显成效。同时阐述随着市场竞争的日趋激烈,该技术将会被越来越多的企业所采用,对企业的发展将发挥越来越重要的作用。     

Rapid prototyping and tooling techniques: a review of applications for rapid investment casting

Investment casting (IC) has benefited numerous industries as an economical means for mass producing quality near net shape metal parts with high geometric complexity and acceptable tolerances. The economic benefits of IC are limited to mass production. The high costs and long lead-time associated with the development of hard tooling for wax pattern moulding renders IC uneconomical for low-volume production. The outstanding manufacturing capabilities of rapid prototyping (RP) and rapid tooling (RT) technologies (RP&T) are exploited to provide cost-effective solutions for low-volume IC runs. RP parts substitute traditional wax patterns for IC or serve as production moulds for wax injection moulding. This paper reviews the application and potential application of state-of-the-art RP&T techniques in IC. The techniques are examined by introducing their concepts, strengths and weaknesses. Related research carried out worldwide by different organisations and academic institutions are discussed.     

Application of rapid prototyping and computational fluid dynamics in the development of water flow regulating valves

Water flow regulating valves are widely used in instant water heaters to vary the rate of water flow. The water flow regulation from the valve has to be linear so that the temperature at the outlet is uniform. The shapes of valve trim affect the flow rate and have to be confirmed before releasing the designs for manufacture. In this project, the flow rate regulating characteristics were improved for a flow regulating valve with the application of rapid prototyping (RP) and computational fluid dynamics (CFD). In the development of flow regulating valves, precise, functional prototypes were required. Design concepts of three valve trim designs were evaluated applying different RP techniques and CFD analysis. Prototypes from different RP systems were used as functional models. Over the product development cycle, RP and CFD analysis stages played an important role particularly in the design selection stage. Finally, comparisons of RP samples from various RP processes and the results of CFD analysis were made on the flow rate and flow regulation. Based on these comparisons, the best design was chosen for manufacture of the valves.     

基于产品配置的快速设计开发研究

针对个性化需求带来的新产品设计开发周期长,成本高的问题,提出基于产品配置的快速设计开发的策略,在工业电机PDM中通过建立特征谱表进行新旧产品的匹配,找到合适的搭配,然后进行产品遗传变异、模块化物料清单、全系列重组进行产品零部件配置,快速得到新产品结构.     

Supporting product development in the textile industry through the use of a product lifecycle management approach: a preliminary set of guidelines

Product Lifecycle Management (PLM) is in some segments, such in the aerospace and defence (A&;D) and automotive fields, a well-known business approach to support product development. However, while these markets recognise the power of PLM, others, such as textile, which searches for more performing solutions to meet the new globalised market competitiveness, still need to take the first steps towards a better understanding of how its processes/features could support the company businesses. For this reason, this paper aims to provide a roadmap about where and how PLM could support the development of textile products, in particular those ones that should be quickly innovated in order to answer to the volatile customers’ demand (fast fashion scenario), adopting a user-centred approach. Starting from a rigorous formalisation of the textile New Product Introduction (NPI) process, weaknesses and strengths have been then formalised via the involvement of NPI stakeholders catching and analysing their needs as users/actors. This set of requirements has been then correlated with the PLM features, through the use of Quality Function Deployment (QFD), in order to define a set of guidelines describing for each NPI process how PLM processes/features could be linked and which benefits could be obtained with this link. These guidelines could help textile companies to have a clearer idea of the advantages that could be obtained through the adoption of the PLM approach. Hence, the proposed methodology is able to provide to the company with a quantification of the impact of the PLM features on its processes. Moreover, it could support vendors to provide their solutions with more tailored features.     

激光熔敷快速制造技术及其精度保证分析

RP技术在当今市场上有较强的优越性。本文分析了快速成型系统的成型原理;重点分析了一种新型激光熔敷快速成型系统;介绍了STL格式模型和利用RP技术的快速性和铸造工艺的成熟性制造功能性产品的CAE系统;并构建了多回路误差控制及反馈系统,从而保证系统的精度。     

The development of a hypermedia maintenance manual for an advanced manufacturing company

This paper addresses the development of a hypermedia maintenance manual (HMM) for a manufacturer of automotive equipment. The primary goal was to reduce the non-productive time of the winding machines by supporting the activities of the maintenance personnel in performing preventive and corrective maintenance. In addition, it was hoped that a HMM could decrease the time required to train inexperienced technicians. Additional considerations were given to keeping as low as possible the production, maintenance, updating and dissemination costs of the HMM, and to its ease of use. The paper describes the development environment and stages of creating a HMM. The views of the maintenance personnel and production managers expressed during the evaluation of the system are discussed and used to identify possible improvements and future research.