MJZ01-121@旅行箱拖手塑料套及注射模具设计
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MJZ01-121@旅行箱拖手塑料套及注射模具设计,机械毕业设计全套
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毕业设计（论文）中期检查表（指导教师） 指导教师姓名： 郭中玲 填表日期： 2014 年 4 月 20 日 学生学号 1000110109 学生姓名 容道乐 题目名称 旅行箱拖手塑料套及注射具设计 已完成内容 开题并做调研，进行翻译； 确定其方案设计； 完成结构设计； 绘制结构草图； 完成相关计算； 完成英文翻译； 绘制装配图； 绘制零件图； 撰写论文； 完成毕业设计。 检查日期： 2014-4-20 完成情况 全部完成 按进度完成 滞后进度安排 存在困难 解决办法 查阅相关资料，并且与指导老师和同学们一起讨论解决方案。 预期成绩 优 秀 良 好 中 等 及 格 不及格 建 议 教师签名： 教务处实践教学科制表 说明： 1、 本表由检查毕业设计的指导教师如实填写； 2、 此表要放入毕业设计（论文）档案袋中； 3、 各院 (系 )分类汇总后报教务处实践教学科备案 nts编号： 毕业设计 (论文 )任务书 题 目： 旅行箱拖手塑料套及注射 模具设计 学 院： 国防生 学院 专 业： 机械设计制造及其自动化 学生姓名： 容道乐 学 号： 1000110109 指导教师单位： 机电工程学院 姓 名： 郭中玲 职 称： 高级工程师 题目类型 ： 理论研究 实验研究 工程设计 工程技术研究 软件开发 2013 年 12 月 9 日 nts一、 毕业设计（论文）的内容 1、 塑件的分析 ； 2、 塑件材料的选用与性能分析（特性及成型工艺参数） ； 3、 拟定模具的结构形式（型腔的数目及排布） ； 4、 浇注系统的设计 ； 5、 分流道的设计 ； 6、 浇口的设计 ； 7、 冷料穴和拉料杆的设计 ； 8、 成型零件的设计 ； 9、 导向机构的设计 ； 10、 脱模推出机构的设计 ； 11、 侧向分型与抽心机构设计 ； 12、 排 气系统的设计 ； 13、 温度调节系统的设计 ； 14、 限位钉设计 。 二 、 毕业设计（论文）的要求与数据 1、 外型尺寸及 配合 精度 必须标注； 2、 使用环境 -10 40 ； 3、 电气性能符合 GB 标准； 4、 外观要求 美观坚固； 5、 根据实际情况确定脱模斜度； 6、 ABS 主要技术指标及工艺参数 ； 7、 设计中的计算 ； 8、 安装尺寸的校 核 。 三、毕业设计（论文）应完成的工作 1、 完成二万字左右的毕业设计说明书（论文）；在毕业设计说明书（论文）中必须包括详细的 300-500 个单词的英文摘要； 2、 独立完成与课题相关，不少于四万 字符的指定英文资料翻译（附英文原文）； 3、 对于纯机械类课题，绘图工作量折合 A0 图纸 3 张以上，其中必须包含两张 A3 以上的计算机绘图图纸 。 nts四、应收集的资料及主要参考文献 1 李学峰 .塑料模设计及制造 M.北京：机械工业出 版 社 ， 2001.1-283 2 翁其金 .塑料模塑成型技术 M.北京：机械工业出版社 ， 2002.1-164. 3 钱泉森 .塑料成型工艺及模具设计 M.济南：山东科学技术出 版社，2004.1-314 4 塑料模设计手册编著组 .塑料设计手册 .北京：机械工业出版社 ， 2002 5 陈剑鹤 .模具设计基础 M.北京：机械工业出版社， 2004.1-287 6 王文广等 .塑料注塑模具设计技巧与实例 M.北京：化学工业出版社，2004.1-164 7 章飞 .型腔模具设计与制造 M.北京：化学工业出版社， 2003 8 谭雪松，林晓新，温利编 .新编塑料模设计手册 .北京：人民邮电出版社，2007.1 9 朱光 .塑料注塑模中小型模架及其技术条件 M.北京：清华大学出版社，2003.1 10 Herbertw.Yankeemanu facturing processes Prentice-Hall,Inc.2006 五、试验、测试、试制加工所需主要仪器设备及条件 计算机 (autoCAD,及 pro/E,protel 软件 ), nts任务下达时间： 2013 年 12 月 9 日 毕业设计开始与完成时间： 2013 年 12 月 17 日至 2014 年 05 月 8 日 组织实施单位： 教研室主任意见： 签字： 2013 年 12 月 14 日 院领导小组意见： 签字： 2013 年 12 月 16 日 nts 编号： 毕业设计 (论文 )开题报告 题 目： 旅行 箱拖手塑料套 及注射模具设计 院 （系）： 国防生 学院 专 业： 机械设计制造及其自动化 学生姓名： 容道乐 学 号： 1000110109 指导教师 单 位： 机电工程学院 姓 名： 郭中玲 职 称： 高级工程师 题目类型 ： 理论研究 实验研究 工程设计 工程技术研究 软件开发 2013 年 12 月 23 日 nts 编号： 毕业设计 (论文 )任务书 题 目： 旅行 箱拖手塑料套 及注射模具设计 院 （系）： 国防生 学院 专 业： 机械设计制造及其自动化 学生姓名： 容道乐 学 号： 1000110109 指导教师 单 位： 机电工程学院 姓 名： 郭中玲 职 称： 高级工程师 题目类型 ： 理论研究 实验研究 工程设计 工程技术研究 软件开发 2014 年 12 月 9 日 nts 编号： 毕业设计 (论文 )说明书 题 目： 旅行 箱拖手塑料套 及注射模具设计 院 （系）： 国防生 学院 专 业： 机械设计制造及其自动化 学生姓名： 容道乐 学 号： 1000110109 指导教师 单 位： 机电工 程学院 姓 名： 郭中玲 职 称： 高级工程师 题目类型 ： 理论研究 实验研究 工程设计 工程技术研究 软件开发 2014 年 5 月 4 日 nts编号： 毕业设计 (论文 )外文翻译 （原文） 院 （系）： 国防生 学院 专 业： 机械设计制造及其自动化 学生姓名： 容道乐 学 号： 1000110109 指导教师 单 位： 机电工程学院 姓 名： 郭中玲 职 称： 高级工程师 2014 年 1 月 14 日 nts编号： 毕业设计 (论文 )外文翻译 （ 译文 ） 院 （系）： 国防生 学院 专 业： 机械设计制造及其自动 化 学生姓名： 容道乐 学 号： 1000110109 指导教师 单 位： 机电工程学院 姓 名： 郭中玲 职 称： 高级工程师 2014 年 1 月 14 日 nts 编号： 毕业设计 (论文 )开题报告 题 目： 旅行 箱拖手塑料套 及注射模具设计 院 （系）： 国防生 学院 专 业： 机械设计制造及其自动化 学生姓名： 容道乐 学 号： 1000110109 指导教师 单 位： 机电工程学院 姓 名： 郭中玲 职 称： 高级工程师 题目类型 ： 理论研究 实验研究 工程设计 工程技术研究 软件开发 2013 年 12 月 23 日 nts 开题报告填写要求 1开题报告作为毕业设计（论文）答辩委员会对学生答辩资格审查的依据材料之一。此报告应在指导教师指导下，由学生在毕业设计（论文）工作前期内完成，经指导教师签署意见审查后生效。 2开题报告内容必须用黑墨水笔工整书写， 或按教务处统一设计的电子文档标准格式打印，禁止打印在其它纸上后剪贴，完成后应及时交给指导教师签署意见。 3学生查阅资料的参考文献应在 5 篇及以上（不包括辞典、手册），开题报告的字数要在 1000 字以上。 4有关年月日等日期的填写，应当按照国标 GB/T 7408 94数据元和交换格式、信息交换、日期和时间表示法规定的要求，一律用阿拉伯数字书写。如“ 2004 年 4 月 26 日”或“ 2004-04-26”。 nts 1.本课题的研究内容、重点及难点 本次毕业设计课题为 旅行箱拖手塑料套及注射模设计。近年来，我国模具工业有了很大的发展，模具与生活越来越贴近，给我们的生活带来了很打的方便。在未来的模具市场中，塑料模具发展的速度将高于其它模具，在模具行业中的比例将逐步提高。拖手塑料套广泛运用于旅行箱中，随着人们出行率的增加，旅行箱的需求也随之增多，模具的使用就是降低拖手塑料套的生产成本并提高生产效率。 此次设计中有许多地方需要仔细研究，其主要内容如下： 1、 查阅资料。结合本次课题查阅相关资料； 2、 撰写开题报告； 3、 通过对产品的性能分析，完成相关的模具结 构与零件设计； 4、 设计的模具结构要求完整、合理； 5、 合理选择尺寸、公差、表面粗糙度和制件材料，绘制的产品图样完整； 6、 认真分析制件图，确定模具型腔、模具结构、分型面和进料口形式，计算含收缩率的相关尺寸和模具的强度和刚度； 7、翻译专业外语文献。 8、撰写毕业设计（论文）说明书； 9、绘制模具装配图和零件图。 毕业设计的重点难点： 1、脱模推出机构和侧抽芯机构的设计； 2、塑件的结构及工艺分析； 3、材料选择及相关参数的计算； 4、模具型腔数的确定，模具结构、分型面和进料口形式的选择； 5、绘制模具总装图、零件图及尺寸标注。 6、注射模具的设计以及加工工艺设计。 2.准备情况（已查阅的参考文献或进行的调研） 21 世纪，塑料工业以前所谓有的速度高速发展，在各个领域乃至国名经济中已拥有举足轻重的地位。 目前，我国塑料工业的高速发展对模具工业提出了越来越高的要求。在 2010 年，塑料模具在整个模具行业中所占的比例已上升到 50%左右，未来几年中，所料模具还将保持高速度发展。模具是工业生产中使用极为广泛的重要装备，采用模 具生产制nts 品及零件，具有生产效率高，节约原材料，陈本低廉，保证质量等一系列优点，是现代工业生产中的重要手段和主要发展方向。 注塑成型所用的模具即为注塑模（也称为注射模），注塑成型的原理（以螺杆式注射机为例）。首先将颗粒或粉状的塑料加入料斗，然后输送到侧装有电加热的料筒中塑化。螺杆在料筒前端原地转动，使被加热预塑的塑料在螺杆的转动作用下通过螺旋槽输送至料筒前端的喷嘴附近。螺杆的转动使塑料进一步化，料温在剪切摩擦热的作用下进一步提高并得以均匀化。当料筒前端堆积的体对螺杆产生一定的压力时（称为螺杆的背压），螺杆将转 动后退，直至整好的行程开关接触，从而使螺母与螺杆锁紧。具有模具一次注射量的塑料预塑和储过程结束。这时，马达带动气缸前进，与液压缸活塞相连接的螺杆以一定的速度和压力将熔料通过料筒前端的喷嘴注入温度较低的闭合模具型腔中。熔体通过喷嘴注入闭合模具腔后，必须经过一定时间的保压，熔融塑料才能冷却固化，保持模具型腔所赋予形状和尺寸。当合模机构打开时，在推出机构的作用下，即可顶出注塑成型的塑料制品。 参考 查阅的文献资料 1 李学峰 .塑料模设计及制造 M.北京：机械工业出 版 社 ， 2001.1-283 2 翁其金 .塑料模塑成型技术 M.北京：机械工业出版社 ， 2002.1-164. 3 钱泉森 .塑料成型工艺及模具设计 M.济南：山东科学技术出 版社，2004.1-314 4 塑料模设计手册编著组 .塑料设计手册 .北京：机械工业出版社 ， 2002 5 陈剑鹤 .模具设计基础 M.北京：机械工业出版社 ， 2004.1-287 6 王文广等 .塑料注塑模具设计技巧与实例 M.北京：化学工业出版社，2004.1-164 7 章飞 .型腔模具 设计与制造 M.北京：化学工业出版社， 2003 8 谭雪松，林晓新，温利编 .新编塑料模设计手册 .北京：人民邮电出版社，2007.1 9 朱光 .塑料注塑模中小型模架及其技术条件 M.北京：清华大学出版社，2003.1 10 Herbertw.Yankeemanu facturing processes Prentice-Hall,Inc.2006 3.实施方案、进度实施计划及预期提交的毕业设计资料 1、 2013 年 12 月 17 日至 2013 年 12 月 30 日，理解消化 毕设任务书要求并收集、分析、消化资料文献，根据毕设内容完成并交开题报告； nts 2、 2013 年 1 月 6 日至 2014 年 1 月 13 日，开展调研，了解塑件结构，对原材料进行分析，考虑塑件的成型工艺性、模具的总体结构的形式，并完成部分英文摘要翻译。 3、 2014 年 3 月 4 日至 2013 年 3 月 31 日，查阅资料，熟悉注射模的结构及有关计算，拟定模具的方案设计、总体设计及主要零件设计，拟定成型工艺过程，查阅有关手册确定适宜的工艺参数，注射机的选择及确定注射设备及型号规格； 4、 2014 年 4 月 1 日至 2014 年 4 月 21 日，完成设计计算任务 ，总体结构的设计和完成总装配图及零件图的设计； 5、 2014 年 4 月 22 日至 2014 年 4 月 30 日，完成设计，图纸绘制任务，工艺规程说明书的编写； 6、 2014 年 5 月 1 日至 2014 年 5 月 4 日，完善设计并完成论文的撰写； 7、 2014 年 5 月 4 日至 2014 年 5 月 7 日，修改并打印毕业论文及整理相关资料，交指导老师评阅，准备论文答辩。 指导教师意见 指导教师： 年 月 日 开题小组意见 开题小组成员签字： 年 月 日 院系审核意见 院系主管领导签字： 年 月 日 nts2014年机电工程学院毕业设计 (论文 )进度计划表 学生姓名： 容道乐 学号： 1000110109 序号 起止日期 计划完成内容 实际完成内容 检查日期 检查人签名 1 2013.12.9 12.15 任务下达书 已完成 2 2013.12.16 12.22 查阅资料 已完成 3 2013.12.23 12.29 调研 已完成 4 2013.12.30-2014.1.5 写开题报告 已完成 5 2014.1.6-2014.1.12 写外文原文及翻译 已完成 6 2014.1.13-2014.1.19 写外文原文及翻译 已完成 7 2014.2.24-2014.3.2 写论文说明书 已完成 8 2014.3.3-2014.3.9 完成框图设计 已完成 (本表同时作为指导教师对学生的 16次考勤记录 ) nts2014年机电工程学院毕业设计进度计划表（续） 学生姓名： 学号： 序号 起止日期 计划完成内容 实际完成内容 检查日期 检查人签名 9 2014.3.10-2014.3.16 完成图纸设计 已完成 10 2014.3.17-2014.3.23 完成说明书初 稿 已完成 11 2014.3.24-2014.3.30 交老师检查 已完成 12 2014.3.31-2014.4.6 第一次回作者修改 已完成 13 2014.4.7-2014.4.13 第二次交老师检查 已完成 14 2014.4.14-2014.4.20 第二次回作者修改 已完成 15 2014.4.21-2014.4.27 打印修改 已完成 16 2014.4.28-2014.5.4 完成毕业设计，提交 论文 已完成 任务下达时间 ： 2013 年 12 月 9 日 (本表同时作为指导教师对学生的 16次考勤记录 ) nts282 Design Results IEEE TRANSACTIONS ON ENGINEERING MANAGEMENT, VOL. 36, NO. 4, NOVEMBER 1989 Work in Change: Social Conditions and of CAD Use in Mechanical Engineering FRED MANSKE AND HARALD WOLF Abstract-The findings presented on the employment of CAD in West Germanys mechanical engineering industry show that CAD is used in various ways by different firms and, thus, also has diverse results on working conditions. The various production structures used by the single- piece, half-standardized, and standardized series producers are consid- ered to be the most important factors for explaining this circumstance. In addition, however, the influence of various interest groups in the firms concerning the introduction process also has to be stressed. In view of their research findings, the authors argue against using the oversimplifications and rash generalizations regarding the reduction of personnel, Taylorism, and deskilling that dominated the discussion during the early days of CAD. They regard the changes taking place at the level of the “microstructures” of designing to be basically the general consequences of the employment of CAD. These changes have until the present had little influence on the division of labor and the development of skills. The latter depend, according to the findings presented in this paper, on the various concepts of CAD utilization. Among other things, the following trends were discovered in this respect: within the field of design, skilled jobs retain their skill level; some already deskilled jobs disappear; the traditional three-way task split into design, detail design, and draftsmen is developing towards a two-way split into design and draftsmen; in addition, new jobs are being created for CAD experts in the fields of CAD development and support; stress is becoming a more important issue for the technicians; traditional, internal career ladders are losing ground; computerized monitoring and control threaten to introduce new ways of binding the design personnel into the design process. I. INVESTIGATING CAD IMPLEMENTATION IN WEST GERMANYS MECHANICAL ENGINEERING INDUSTRY ECHANICAL engineering is one of the most important M branches of West German industry, with about one million employees and an export surplus of some DM 50 or 60 billion annually. It has been able to achieve its internationally recognized leading position above all because it does not manufacture standardized mass products but is rather con- cerned with the specific wishes of clients looking for tailor- made, problem-solving answers. As a consequence of this specialization, small and medium-size firms producing single products or small batches predominate in West Germanys Manuscript received September 9, 1988; revised March 14, 1989. The review of this paper was processed by A. Majchrzak and H. Salzman. This paper contains interim findings from the research project “Requirements of and the Approach to Humane Work Organization in Computer-Aided Design and Planning Processes,” financed by BMFT and supervised by “Projekttra- ger Fertigungstechnik” at the Nuclear Research Centre, Karlsruhe, West Germany. It is currently being carried out at SOFI, Gottingen, West Germany. The authors are with SOFI, 3400 Gottingen, West Germany. IEEE Log number 8929661. mechanical engineering industry. As can been seen in Table I, the significance of small firms in West Germanys mechanical engineering industry has increased. It is clear that design and planning activities are especially important in this form of production, which has to implement production innovations and variations at frequent intervals. This is demonstrated by the fact that some 10-30 percent of the employees work in the designing and operations planning departments in the mechanical engineering firms we have been investigating. The findings of two representative surveys on employment structures in West Germanys mechanical engineering indus- try are presented in Table I1 (the findings from the most recent survey, made in 1988, are unfortunately not available yet). The most significant finding is that the fields “product development and design” and quotation processing and project planning have also gained in importance quantita- tively: in 1976, 10.5 percent of those employed in mechanical engineering worked in these areas (I. 1 and 1.2 in Table 11), in 1984, the percentage increased to 12.3 percent. The percentages given here are averages. In our investiga- tion, the percentages referring to the employees in these job areas are spread out between 5 and 30 percent. In the case of the series producers, the percentage is lower (as low as 5 percent) and in the case of the single-piece producers, it is higher (as high as 30 percent). For more information on the types of producers, see Section 11. For several years now, a broad spectrum of techniques has been available in the shape of CAD, PPS, CAP, and NC programming systems that offer the mechanical engineering industry possibilities to rationalize design and planning activi- ties. It even seems as if it would be possible to technically integrate the various task functions in the field of design and, even further, to fuse it with work planning and NC program- ming, a fusion that in the end would include CNC machines and from which significant effects for and on rationalization and flexibility can be expected. However, it should be mentioned that the technical integra- tion in the majority of the firms is not very advanced: heterogeneous computer and system landscapes still dominate the picture. The employment of CAD itself in mechanical engineering is still not self-evident. This is in contrast to the case of the industries that can be considered advanced in this sense, such as automobile and airplane construction, where it has been, in the meantime, a proof of technical perfection if certain products are more or less completely developed using CAD (cf., e.g., l). According to a recent survey made in 1986 2, 0018-9391/89/1 100-0282$01 .OO 0 1989 IEEE Authorized licensed use limited to: GUILIN UNIVERSITY OF ELECTRONIC TECHNOLOGY. Downloaded on March 05,2010 at 00:18:17 EST from IEEE Xplore. Restrictions apply. ntsMANSKE AND WOLF: DESIGN WORK IN CHANGE 1972 1981 Number Em- Turn- Number Em Turn- Firms ees % of ploy- over of ploy- over Firms ees % % % Small Firms (20 to 199 Em- 3603 22.2 19.6 ployees ) 4026 25.3 21.2 283 1986 Number Em- Turn- Firms ees % % of ploy- over 4114 26.4 23.5 TABLE I FIRMS, EMPLOYEES, AND TURNOVER IN MECHANICAL ENGINEERING ACCORDING TO SIZE Large Firms Employees) (500 or More 470 56.4 59.3 448 54.5 59.6 433 53.5 58.5 _ I. Design and Planning 14.2 Activities (1+2+3) - Sum I 48111) 98.11) 98.9l) I 5193 100 100 1 5260 100 100 In 1972, firms with lo to 19 employees were surveyed. the figure in order to be able to compare the findings from 1972 with those of They were not included in 16.0 1986. The absolute number of employees was: 1972, 1,163 million; 1980, 1,099 million; 1986, 1,085 million. The turnover percentages refer to the month of September of each year. 3. Operations Planning 11. Other Activities 4. Material Control and (4t5t6t7) Management 5. Production and Assembly 6. Administration 7. Sales Department I. t 11. Source: VDMA, Statistisches Jahrbuch fur den Maschinenbau: 1975, 1983 and 1988. 3.7 3.7 71.4 74.9 4.7 4.8 54.8 52.2 9.3 8.6 8.6 9.3 91.6 90.9 TABLE II DEVELOPMENT OF THE EMPLOYEES IN MECHANICAL ENGINEERING ACCORDING TO JOB ACTIVITY (PERCENTAGE OF TOTAL EMPLOYEES) Total I I 1976 I 1984 100.0 100.0 I 1. Product Development and Design I 8.67 I 9.7) 2. Quotation Processing, Project Planning I 111. Vocational Training I I 8. Trainer 9. Trainee 0.5 0.5 I 7.9 I 8.6 Source: VDMA, Abteilung Betriebswirtschaft und Informatik; Statistisches Handbuch far den Maschinenbau 1981 and BWZ 50. Sept. 1985. Authorized licensed use limited to: GUILIN UNIVERSITY OF ELECTRONIC TECHNOLOGY. Downloaded on March 05,2010 at 00:18:17 EST from IEEE Xplore. Restrictions apply. nts284 IEEE TRANSACTIONS ON ENGINEERING MANAGEMENT, VOL. 36, NO. 4, NOVEMBER 1989 p. 91, over 80 percent of the mechanical engineering firms still did not employ CAD. The minority, comprising about 18 percent, that utilized CAD at the time used it at a completely different level. Many are still involved in an introductory phase. In most of the mechanical engineering firms, the dominating situation is, in all probability, that one would find a few CAD workplaces confronted by many “conventional” workplaces. Our research project has, in the face of this situation, to study, above all, the following questions: *What are the task structures in the design and planning departments of West Germanys mechanical engineering industry? *Which qualifications and skills are required of the employ- ees as a result of the task functions and their organizational bundling so that they form jobs? *Which forms of cooperation can be found in the technical offices? What chances and paths are there for advance- ment? And naturally, it was necessary to study what changes take place in these structures as a result of the implementation of new techniques. The introduction of these new techniques in mechanical engineering represents a process that generally takes several years. The character of the process corresponded to our research procedure: the surveys were conceptualized as longitudinal studies. The introductory processes were to be observed over a period of three to four years. The firms included in the survey were chosen on the basis of a preliminary test. The targets were on the one hand, to choose firms that produced different products; then again, they should be of different sizes (number of employees); finally, we also wanted to find firms that were a bit further advanced in the implementation process. When choosing the firms, we were able to draw on two previous studies we had done on the employment of produc- tion planning and control systems (PPS) that were carried out from 1981 to 1985 3, 4. Our knowledge of West Germanys mechanical engineering industry was in other words, already quite comprehensive. In the end, we chose ten firms: three machine-tool builders, as well as one manufac- turer each of printing machines, bookbinding machines, escalators, screen-printing machines, machines and systems for shaping steel, road construction machines, and supplies of the electrotechnical industry. The smallest firm included in the survey employed 60 people, the largest over 2000. Firms with more than 500 employees are clearly overrepresented. This is a result of the fact that the employment of the new technology is already more widely spread in these firms (cf. 2). The survey was carried out in the firms in three phases. The first phase involved preliminary investigations. This was followed, about four months later, by intensive surveys (approximately two weeks per firm). Finally, after approxi- mately one more year, there were intensive surveys (approxi- mately one week per firm). Expert talks were held with everyone from the heads of the firms to the heads of the de- partments (approximately two hours in length; a total of 129 talks) and intensive on-site job investigations that consisted of observations and talks (approximately four to eight hours in length; a total of 67 investigations). Included in the on-site job investigations were designers (36); technical draftmen, male and female (12); operation planners (7); and NC programmers (12). All in all, it is a qualitative study. The findings, therefore, do not allow any generalized conclusions. On the basis of our comprehensive knowledge, however, it is possible to make qualitative statements on trends. In this paper, we will concentrate on that part of the survey that dealt with CAD and design. This is possible from the viewpoint of the contents because, according to our investiga- tions, even in the case of ties between CAD and NC programming systems the tasks in design and work planning remain clearly separated. On the other hand, it is impossible to present both subjects thoroughly as a paper is too short to be able to handle both properly - CAD and design, CAD + NC programming and work planning. Furthermore, we abstract from the problems of product complexity to a large extent. The presentation focuses on those factors that, from our point of view, most significantly determine the various areas and forms of employing CAD and the consequences of the CAD employment for designers, detail designers, and techni- cal draftsmen. II. TRADITIONAL FORMS OF DESIGN IN MECHANICAL ENGINEERING A. Types of Production and Design The individual companies can deal with the situation within the branch as described above in various ways. This also has its effects on the importance and form for the design process. One can differentiate three types of production: a) single-piece production, b) half-standardized production with custom-made variations, and c) standardized production in fairly large series. As a rule, firms belonging to category a) manufacture products tailored to the specific demands of the customer. Consequently, each special order requires a high expenditure of design work to be completed within the narrow time limits dictated by the delivery date. In contrast, the producer of series c) manufactures “ready-made” items and has a larger number of his standard products in stock. In this connection, product design does not depend on the individual client. Accordingly, it is detached from the actual production process as far as its time requirements are concerned. Firms belonging to category b) combine characteristics of both the single-piece producer and the series producer. The differences, which are only briefly mentioned here, in the design process in the firms have until now played an important role in the development of the different concepts of CAD employment which will have to be discussed further on in this paper. Among the firms included in our study sample are series producers that manufacture between 1000 and 2000 machines per year. The total production covers various types of machines that are offered by the firms. One enterprise, for example, offers eight different types of machines: manual “universal” milling and drilling machines, small CNC milling and drilling machines, Authorized licensed use limited to: GUILIN UNIVERSITY OF ELECTRONIC TECHNOLOGY. Downloaded on March 05,2010 at 00:18:17 EST from IEEE Xplore. Restrictions apply. ntsMANSKE AND WOLF: DESIGN WORK IN CHANGE 285 large CNC milling and drilling machines, machining centers, high-production machining centers, flexible manufacturing systems, engraving and duplicating milling machines, tool-grinding machines. A series produced at any one time can amount to as many as approximately 100 machines. Usually, however, the total is lower. The single-piece a) and half-standardized b) producers manufacture a total of between 40 to 150 machines per year. The products are always single units. B. “Product Experience” and Team work in Traditional Design Offices The typology of work in design offices is relatively diverse and is divided among development and calculation engineers, draft designers, detail designers, and draftsmen. Very few graduate engineers have until the present been employed in these jobs in West Germany. The typical trend has been, instead, to choose people - even for the most demanding positions within the job hierarchy-on the basis of long experience and skills gained on the job. These employees were often skilled workers who worked their way up. In most firms, the technician or draftsman is expected to gain higher qualifications during the course of his time spent on the job. It would, therefore, be inappropriate to conclude on the basis of a brief glance at the relatively refined task structures that there are very permanent and solid lines demarcating the division of labor in design departments. The transitions are, on the contrary, “soft” and flowing and promote the necessary flexibility. In addition to product and component specialization and subdivision within the departments, this flexibility is often characterized by a “task force” organization during which various specialists (designers, detail designers, draftsmen) cooperate for a fixed period of time on a particular task required by a specific order. Such varying forms of coopera- tion, which frequently change and offer diverse ways of approaching a problem, present an opportunity to work with sundry aspects of the object and, thereby, offer the chance to accumulate knowledge closely related to different products and tasks. The great significance of this “knowledge gained through experience” in the company is a result of the fact that the design process in principle normally uses, although it may take on a number of variations, familiar solutions specific to the particular firm and the particular product. So far this has hardly required any advanced theoretical or academic skills which could be acquired outside the process itself. This is also the reason for the “permeability” of the work structures which makes it easier to make “careers” on the basis of advancement within the firm. Essentially there are two factors which, today, have made these working conditions (which had
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