GT—CAD系统与相似零件设计标准化

本文叙述了用分级法进行相似件设计标准化的问题,并对 GT—CAD 程序及 GT—CAD 与 CAD 的主要区别作了探讨。     

Teaching for CAD expertise

CAD (Computer Aided Design) has now become an integral part of Technology Education. The recent introduction of highly sophisticated, low-cost CAD software and CAM hardware capable of running on desktop computers has accelerated this trend. There is now quite widespread introduction of solid modeling CAD software into secondary schools but how much is really known about the processes of learning and teaching CAD, particularly solid modeling? This paper will discuss current practice in CAD teaching and the way this relates to solid modeling. It will discuss the findings of current research with particular emphasis on the difference between command knowledge and strategic knowledge and how this relates to the development of CAD expertise. Command knowledge is referred to as knowledge of the commands (algorithms or tools) and the procedures to use those tools within CAD software while strategic knowledge is concerned with knowledge of the alternate methods by which a specific task may be achieved and the process by which a choice may be made. The results of a recent experimental study into the teaching of CAD expertise will then be outlined and the implications for the teaching and learning process will be discussed.     

Aligning a CAD course constructively: telling-to-peer and writing-to-peer activities for efficient use of CAD in design curricula

International Journal of Technology and Design Education - As the literature points out the lack of efficient use of Computer-Aided Design (CAD) in design curricula, we aimed to align a CAD course...     

Do computers improve the drawing of a geometrical figure for 10?year-old children?

Nowadays, computer aided design (CAD) is widely used by designers. Would children learn to draw more easily and more efficiently if they were taught with computerised tools? To answer this question, we made an experiment designed to compare two methods for children to do the same drawing: the classical ‘pen and paper’ method and a CAD method. We asked two groups of 14 children to draw a geometrical figure: the Rey-Osterrieth Complex Figure (ROCF). The first group drew it with a pen on a sheet of paper (‘paper’ group) and the second on a computer screen with CAD software (‘computer’ group). Two drawing conditions were studied: ‘Copying’ the figure and drawing from memory. Results showed that the ‘computer’ group was better at copying the figure but that both groups performed equally well when the figure was drawn from memory. These preliminary results suggest that using a CAD tool could help children while they copy a model, but that it does not improve their ability to draw the same figure using their own, internal model.     

Heuristics and CAD modelling: an examination of student behaviour during problem solving episodes within CAD modelling activities

Design activities typically involve and culminate in the creation of models representative of new ideas and conceptions. The format is often dictated by the specific discipline, with ideas in design and technology education regularly being externalised through the use of computer aided design (CAD). This paper focusses on the realisation stage of a design process, specifically when conceptual ideas are being externalised through CAD. Acknowledging students as novices or quasi-experts with regards to their levels of technical expertise and recognising the limitations in the cognitive capacities of humans suggests merit in investigating problem solving strategies through the lens of heuristics. A comparative study was employed between two distinct CAD systems to examine students modelling behaviour. Considering the situational context of the problems encountered and the bounded rationality which the students are operating within, a number of insights are generated from the findings which are of importance from a pedagogical perspective within design and technology education.     

机械CAD/CAM的现状与发展趋势

回顾和总结了机械ＣＡＤ／ＣＡＭ近三十年的发展历程，概述了国内外ＣＡＤ／ＣＡＭ的研究与应用现状，介绍了几个较为著名的 ＣＡＤ／ＣＡＭ软件，对未来 ＣＡＤ／ＣＡＭ的发展进行了论述。     

地理测绘中的三维CAD技术

在测绘过程中,将CAD技术运用于地理地形绘图中,能够大大提高绘图效率。在地理制图测绘中,三维CAD可以对地质测绘的结果通过相关的绘图软件进行编辑处理,然后用绘图的方式把最终结果输出,在整个地质勘探的过程中是一个不可或缺的环节,经过CAD处理以后能够将复杂的地形地势的绘制简单化,降低绘图过程中可能出现的失误。但由于三维CAD没有普及,运用在地理测绘中,出现了许多问题,本文对这些问题进行了总结,并提出了有效地解决方案。     

服装CAD课程建设与教学改革研究

通过文献搜集和实地调研等方法进行相关研究,得出服装CAD课程的教学现状种种不足,在此基础上,提出通过其软硬件建设、师资队伍建设以及网络课堂建设等三个方面完善服装CAD课程建设工作,并从教学内容、教学方法以及教学评估等方面对服装CAD课程进行教学改革尝试,以期更好地促进服装CAD课程的教学完善。     

服装CAD中的图例库及图块研究

服装CAD中存在许多常用部件,针对这些部件开发服装CAD图形库和图块功能可以提高制图的效率,并且图块功能是CAD软件中的重要功能之一。本文结合服装纸样工程的实际情况,提出一种服装纸样图例库建立和图块功能的可行方法,并应用VisualC++开发了此功能,在实际运用中良好运行。     

Back‐loading: A Potential Side Effect of Employing Digital Design Tools in New Product Development

Over the past 20 years, the use of digital design tools such as Computer‐Aided‐Design (CAD) has increased dramatically. Today, almost no product development project is conducted without the use of CAD models. Major advantages typically ascribed to using CAD include better solutions through broader exploration of the solution space as well as faster and less expensive projects through faster and earlier iterations. This latter effect, the shifting of simulation and testing traditionally accomplished with the help of physical prototypes late in the process—a slow and expensive activity—to doing similar activities with virtual prototypes faster and earlier in the process, has been identified as a key aspect of front‐loading, an activity shift promising to enable superior product development (PD) performance. Given CAD's recent pervasive use, the research questions for this paper became “how has CAD use actually changed the way in which product development is conducted, and through which mechanisms and pathways can CAD impact PD performance, especially with respect to the idea of front‐loading?” This paper addresses these questions by studying in a longitudinal comparison in detail two similar product development projects, one conducted in 2001, the other in 2009. The projects were carefully selected to isolate the substantially higher levels of CAD use of the second project while controlling for most other input factors that influence project performance. The project with substantially higher use of CAD exhibited significant improvements in prototyping costs but only marginal changes in project time and project engineering labor cost relative to the project with lower CAD use. In‐depth intra‐project analysis on the phase level reveals that the use of CAD affected how the product development was executed, with both positive and negative consequences. In addition to, and separate from positive aspects of front‐loading, unintended consequences in the form of back‐loading work are also observed. Back‐loading can occur in two places in the product development process: First, the availability of CAD systems can cause an early jump into detail design, effectively shortcutting concept development. Second, the ability to relatively quickly conduct small changes virtually to the design can erode process discipline; late changes are made simply because they are possible. Both of these effects back‐load work in the opposite direction of the positive front‐loading. The theoretical implications of our observations are discussed, and a simple framework to convert our findings into managerial advice is proposed.     

Communication and co-operation in product development: a case study of a European car producer

Continuous innovations in product and process technology, coupled with time-to-market pressure, have made rapid product development a key strategic objective of manufacturing firms. Consequently, many firms have started to define the ways in which products are designed, developed and produced, so as to reduce the time from conception to manufacture. The strategies employed to achieve this goal vary, and include the integration of functions through selective use of concurrent engineering, the formation of strategic project teams, and technological connections by CAD/CAM systems. The research reported in this paper, co-ordinated by the WZB Institute of Berlin, is aimed examining organizational, technological and human resources practices that enhance quality in R&D by improving communication and co-operation C&C) between the actors. Although the research was carried out in four countries(Germany, Italy, Japan and the USA) and in three sectors (car, personal computer and machine tools) this paper analyses the evidence provided by a set of face to face interviews of the managers, engineers and designers of a European car producer.     

二维零件数控火焰切割的自动编程

提出了一种由ＡｕｔｏＣＡＤ二维图形直接生成数控火焰切割机加工代码的方法,为从ＣＡＤ到ＣＡＭ提出了一种简单有效而且实用的途径。     

关于矩形花键轴插齿刀的新研究

本文给出了矩形花键轴插齿刀的无设计误差方法,并给出了相应CAD/CAM 几何模型与渐开线齿形模型的差异,最后还用实例计算验证本文方法与模型的可靠性。     

用AUTOLISP实现分马力电机可变尺寸图形的绘制

AUTO LISP 是嵌套在 AUTO CAD 绘图软件包中的一种功能很强的智能语言,可在绘图软件包环境下直接运行,是一种很适合绘制“可变尺寸图形”的方法。本文详细地研究了 AUTO LISP 源程序编制、在系统状态下编辑程序和在 HCAD 状态下绘图等内容。对 AUTO CAD 的开发应用具有重要作用。     

CAD—The‘Taylorisation’of drawing office work?

CAD has been described as a'Trojan horse'through which drawing office work will be deskilled. This article rebuts the crude Tayloris-ation thesis which underlines such views and offers an alternative analysis of the effects of CAD .     

分马力电机CAD绘图系统的开发与应用

本文详细论述和介绍了开发分马力电机 CAD 绘图系统时的硬件、软件配置,以及在应用 AUTO CAD 办件时所进行的二次开发工程,实现了分马力电机设计中零部件图及总装配图的自动绘制.     

如何用C语言开发CAD应用软件

为了促进用C语言开发CAD应用软件在机械设计、工程分析、化学工程等领域的应用，在此通过实例简单介绍了AutoCADR12forWindows版本ADS应用程序开发环境以及如何用ADSC语言开发CAD应用软件的方法，包括应用程序的创建、加载和执行等。     

Learning CAD at university through summaries of the rules of design intent

The ease with which 3D CAD models may be modified and reused are two key aspects that improve the design-intent variable and that can significantly shorten the development timelines of a product. A set of rules are gathered from various authors that take different 3D modelling strategies into account. These rules are then applied to CAD strategic-knowledge learning methodology and included in 3D CAD modelling exercises for students following the degree in mechanical engineering at the University of Burgos (Spain). The experiment was conducted in two groups with a total of 75 students. The design-intent rules were introduced in the different exercises that the teacher explained in both the theoretical and the practical classes. In addition, a summary of the different design rules in each of the practical exercises was explained in the practical classes in only one of the groups. The experimental results, reported in this paper, tested the influence of these summaries on overall improvements in 3D modelling and on the design-intent variable, which is subdivided into four sections: skeleton, structures, alterations and constraints. The use of the summaries of the design intent rules led to statistically significant improvements in 3D modelling in the experimental group, in comparison with the group of students to whom those summaries were not explained.     

基于AutoCAD的CAD/CAPP集成系统研究

鉴于国内外CAD/CAPP集成的现状,应用AutoCAD环境下的二次开发工具ObjectARX技术,能够和AutoCAD共享空间并直接和AutoCAD进行通信读取零件图形数据库中的几何和工艺信息,从而实现了零件二维图形信息的自动获取,并通过ADO数据库绑定技术完成了对数据库的写入、修改、查询等操作,避免了零件信息的二次输入和人工输入的错误,最终实现了CAD/CAPP的无缝集成。     

CAD与赤平极射投影法在边坡稳定分析中的应用

在露天矿边坡稳定性分析时,可根据边坡内结构面和边坡形态的空间组合关系,利用赤平极射投影法对其稳定性进行初步分析,确定可能的滑塌模式及滑塌范围。通过对赤平极射投影法原理的介绍,以平面投影为例,分析对比了传统画法与CAD图解法的过程,表明CAD图解法作图效率更高。结合具体工程实例应用,证明了该方法在边坡稳定性分析中具有良好的实用性。