Creating machinable textures for CAD/CAM systems

Texture is applied on three-dimensionally modelled surfaces in computer graphics to enhance visual effect. This research focuses on the development of three-dimensional textured surfaces which are suitable for manufacturing. Three approaches for creating the three-dimensional texture are presented.The first approach is to process a design from either an artist's sketch or an image from a two-dimensional scan. The second approach uses a three-dimensional scanned texture. Both these approaches depend on the quality of the scanned image and are more tedious than the third approach, which is to convert texture using parameters and is a more direct approach. In the user interface design, two custom-made forms are developed to cater for both regular and irregular textures.The case studies have shown that the textures created are not only good for a visual effect, but are also machinable. The development work is incorporated into the ArtCAM system which is a specialised CAD/CAM system that is capable of generating three-dimensional shapes from two-dimensional artwork.     

Selecting and prioritizing key factors for CAD/CAM software in small- and medium-sized enterprises using AHP

In today’s fast-paced world, computer-aided design/computer-aided manufacturing (CAD/CAM) systems have become a necessary element in manufacturing industries. Prior to investment in a CAD/CAM system, it is essential for investor to know how to maximize their benefits from buying a new or by changing an existing CAD/CAM system. The purpose of this study is to provide a methodology to assist small- and medium-sized manufacturing companies of Pakistan in selecting a CAD/CAM system. It will also facilitate the software providers in recognizing the current state of affairs as well as preceding problems regarding the application of CAD/CAM in manufacturing firms when assisting them in choosing the direction for future development simultaneously. To accomplish this purpose, data have been collected about current CAD/CAM systems. Important criteria for system selection and parameters for evaluation have also been identified and prioritized. Analytic hierarchy process (AHP) is used as a decision-making technique for identifying and prioritizing important factors for CAD/CAM software selection. Expert Choice (AHP-based software) has been used to validate the results.     

一种有效提高紧缩场反射面精度的CAD／CAM技术

介绍了一种利用计算机技术和数控技术对反射面进行加工的CAD／CAM技术，从加工精度、加工工艺、生产周期等方面对比分析了这两种成形方法。加工成形后经过三坐标测量，对测量结果分析得精度为15．4μm，较反射面板蜂窝夹层结构成形技术的精度极限（20μm）提高了近5μm。经用户使用证明，它是一种可以提高紧缩场反射面精度的新方法。     

Interface between CAD and Rapid Prototyping systems. Part 2: LMI — An improved interface

The STL (STereoLithography) file format, as developed by 3D Systems, has been widely used by most Rapid Prototyping (RP) systems and is supported by all major computer-aided design (CAD) systems. However, it is necessary to improve the STL format to meet the development needs of RP technologies. In Part 1, several existing and proposed formats have been discussed. This paper, Part 2, will present an improved interface between CAD and RP systems. The new interface is a file format that supports the STL format, removes redundant information in the STL format and adds topological information to balance storage and processing cost. In addition to supporting facet boundary models, the new interface supports precise models by using the edge-based boundary representation. This paper discusses the design considerations of the new interface and data structures for both facet models and precise models. Finally, a comparison of the new interface and the STL file format will be made.     

基于特征的回转类零件CNC／CAD／CAM集成系统开发研究

针对回转类零件的结构及加工特点,建立了基于特征的全局统一数据模型及在该模型上实现的回转类零件CAD／CAM集成系统的系统结构,以及以该模型为基础的设计制造支持软件体系,构造了基于工业PC机的开放式数控系统的控制软件和应用软件体系框架,并实现了基于开放式数控系统的回转类零件的集成化制造。     

注塑产品及其模具快速设计系统的研究

根据注塑产品及其模具设计制造的特点,阐述了以 Pro/E、EM X4.1为主线的产品及模具设计平台,为模具设计系统提供了一条快速而有效的途径。     

模具制造中的并行工程研究

并行工程是保证模具交货期和质量的有效手段。本文通过分析模具制造的特点和我国模具制造企业存在的问题,从组织机构和技术手段两方面,对实施模具并行工程的可行性进行了论证,提出了模具制造并行工程的基本框架和实现模具并行工程的关键技术以及实现这些关键技术的手段和方法。这些方法已在注塑模和压铸模的设计制造中得到部分应用,取得了很好的效果。     

空间凸轮刀位补偿加工方式中理论加工误差的研究

开展空间凸轮廓面的非等价加工研究是实际生产的需要,刀位补偿加工方式因其加工效率高,成本低而受到研究者的重视。运用等距曲面理论对“刀位补偿加工必然存在理论徊工误差”的命题进行了理论证明,探讨了刀位补偿加工的基本思想,推导出了刀位补偿加工中的凸轮廓面综合的数学模型,给出了相应的计算机实现算法。     

Inspection Planning Strategy for the On-Machine Measurement Process Based on CAD/CAM/CAI Integration

The objective of this research is to develop an effective inspection planning strategy for sculptured surfaces in the OMM (on-machine measurement) process. As a first step, effective measuring-point locations are determined to obtain optimum results for given sampling numbers. Two measuring-point selection methods are suggested in this study based on newly proposed CAD/CAM/CAI integration concepts: 1. By the prediction of cutting errors. 2. By considering cutter contact points to avoid the measurement errors caused by cusps. As a next step, the TSP (travelling salesman problem) algorithm is applied to minimise the probe moving distance. Appropriate simulations and experiments are performed to verify the proposed inspection planning strategy in this study, and the results are analysed.     

复杂电子装备CAM标准体系构建研究

复杂电子装备是高端制造的典型代表,推进复杂电子装备计算机辅助制造(Computer-Aided Manufac-turing,CAM)技术及标准化发展,是制造强国战略在电子行业的落地.文中以复杂电子装备数字化制造转型升级需求为指引,开展复杂电子装备CAM标准体系研究,从顶层策划研究制定体系布局,构建覆盖基础共性标准、关...     

基于网络的数控制造技术

通过研究现代网络技术、CAD／CAM与数控制造技术集成在模具制造的可行性,证实了网络制造这一先进制造技术在数据传输、故障诊断、远程控制以及大容量数控程序加工等方面较传统数控制造技术具有很大的优越性。该技术在常柴股份有限公司的网络数控改造中得到了成功地应用。     

A geometrical approach to computer-aided process planning for computer-controlled machine tools

This paper documents part of a research program which has been under way at the CIM Centre at Swinburne University of Technology since 1989. The purpose of the research program was to develop an open-architecture machine tool control system and then to see how that system could be used to change the distribution of traditional manufacturing design, planning and control functions. This paper examines one part of that research program and focuses on a methodology which could prove to be useful in the machine tool selection, cutter selection and cutter path generation phases of process planning for cutting operations on workpieces in computer-controlled machine tools.It is suggested that a configuration space transform be used for each cutter/machine tool combination to find the volume that the combination could remove from the uncut workpiece without removing any of the material that will form the final workpiece. A method of comparing these volumes from different combinations is then outlined. The output of this method is a reasonable sequence of machine tools and cutters. Path planning can then be carried out for each of the chosen combinations using a method similar to the one used to find the possible volume to be removed.Possible implementation techniques, and their limitations on existing computer hardware, are discussed and the most promising of these are identified, based upon some properties of configuration space transforms.     

建立制造技术信息网络实施产品制造绿色通道

首先阐述制造业信息化的内涵，指出建立CAD／CAM／CNC一体化制造自动化网络系统，其根本目的是减少浪费和提高效益，使我国制造业更加具有竞争力。然后介绍了柳工的企业制造网络CAD／CAM／CNC一体化的发展应用及产生的效益，并对柳工通过制造信息化改造传统产业的前景进行了展望。     

基于多智能主体的冲模并行设计

探讨将并行工程技术应用于冲模设计的方法，提出基于多智能主体的冲模并行设计方案，并对其中的一些关键技术问题进行讨论。     

Algorithms for computer-aided generative process planning

Process planning is the function within a manufacturing facility that establishes the machining processes and parameters to be used so as to convert a piece-part from its initial form to the final form predetermined on an engineering drawing. Computer-aided process planning (CAPP) has become a major focus of manufacturing automation as it forms the interface between computer-aided design (CAD) and computer-aided manufacturing (CAM). Issues in CAPP include part representation, process selection, alternative process-plan generation, intermediate surface and tolerance determination, and operation sequencing. This paper focuses on quantitative models for determining cutting dimensions and tolerances for intermediate surfaces, and on a heuristic for sequencing cutting operations.     

计算机三维人体模型的参数化几何造型

利用ObjectARX和面向对象技术,开发了一个坐在轮椅上的人体模型的应用程序。轮椅模型和人体模型的生成均实现了参数化。构造人体模型的数据采用国标GB10000-88中国成年人人体尺寸。该模型将用于计算机辅助居室设计和家具设计。     

CAD/CAM技术及应用对我国机械制造业的影响

分析了我国机械制造业和CAD/CAM技术的现状,预测了它们未来的发展趋势,指出了CAD/CAM软件开发应遵循的原则,阐述了CAD/CAM技术及应用的发展对我国机械制造业的巨大影响和深远意义.