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啤酒瓶 全自动 装箱 设计 江苏

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啤酒瓶的全自动装箱机设计（江苏）,啤酒瓶,全自动,装箱,设计,江苏

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J I A N G S U U N I V E R S I T Y本科毕业设计说明书 啤酒瓶的全自动装箱机设计The design of automatic packing machine of beer bottle学院名称： 机械工程学院 专业班级： 机械设计制造及其自动化0301班 学生姓名： 瞿筱烨 指导教师姓名： 范真 指导教师职称： 2007年06月啤酒瓶全自动装箱机说明书摘 要当今社会，人们的生活水平越来越高，于是，越来越多的人喜欢喝瓶装饮料，啤酒、橙汁、矿泉水，于是，对于饮料包装机械的要求越来越高了。如今的关于这方面的新闻真是越来越多了。比如说法国Aries Packaging公司在2005年国际包装展（interpack）上推出新一代装箱机；多功能全自动装箱机在中德合作江西德赛特包装机械设备有限公司诞生由此可见，瓶装装箱所用的装箱机已经成为了罐装饮料生产线上的一道必要工序。现在，我们最常见的装箱机一般是由抓头充、排气来实现抓、放瓶子的。通过机械的运转、气动和电控把瓶子准确、可靠地放进箱子里。并且通过独特的四连杆机构，使瓶子的提升和降落运动准确平稳。随着社会的不断进步，科技的快速发展，全自动装箱机也在不停的发展。本文介绍了其工作原理，气动原理，总体方案设计和进瓶抓瓶部件的设计过程。关键词：全自动装箱机；双四连杆机构；抓瓶头；导瓶装置；The paper of automatic packing machine of beer bottleAbstractToday, more and more people prefer to drink bottled drinks, like beer, orange juice, mineral water and so onSo, the demand of packaging machineries is increasing very fast. There are a lot of news of the packing machine. For example, Aries Packaging, France Corporation was on the launch of a new generation of packing machine in the international packaging exhibition (interpack) in 2005. Multifunction automatic packing machine was produced in which, Jiangxi Dorset Packaging Machinery Equipment Co. Ltd, with Sino-German cooperation.Bottled packing crates used by the machine have become a necessary process of a canned beverage production line. The most common packing machine is the first fully grasp the exhaust to grasp and put the bottles. The machine controls by mechanical operation, pneumatic and electric control to put bottles into boxes accurate and reliable. Through a unique four-bar linkage, the machine put bottles with a accurate and smooth movement. As society progresses, the rapid development of science and technology, automatic packing machines have been undergoing development.And this paper introduces its working principle, aerodynamic principle, the overall program design and the design of components of bottle grasping.Key Words: Automatic packing machine，twin four linkage mechanism，,claw，the device of transportation bottles 目 录引言 1 第一章 装箱机工作原理 1.1 装箱工作原理 21.2 装箱过程的运动分解 21.2.1 瓶的运动 21.2.2 箱的运动 31.2.3 抓头部分的运动 4 1.3 工作原理流程图 5第二章 机械结构总体设计2.1 输瓶装置和导瓶装置 6 2.1.1输瓶装置 6 2.1.2导瓶理瓶原理 62.2 输箱装置 7 2.2.1输箱带II 9 2.2.2输箱带I 9 2.2.3输箱带上的光电管102.3 主传动机构 10 2.3.1 主传动机构的四种状态11 2.3.2 收缩盘 112.4 连杆机构 12 2.4.1 机构的分解 12 2.4.2 轴衬套 142.5 抓瓶装置 15第三章 气动控制原理 16第四章 进瓶及抓瓶装置设计 4.1 进瓶装置 17 4.1.1导瓶板的设计174.1.2 输瓶带 184.1.3 电动机的选配184.2抓瓶装置 19 4.2.1 抓头定位 19 4.2.2 气缸选配 20 4.2.3 安全装置 20第五章 进瓶抓瓶常见故障及处理21第六章 安全22结论 23致谢 24参考文献 25 对全自动装箱机的初步研究机械工程学院 机制0301班 3030301002 瞿筱烨摘要：法国Aries Packaging公司在2005年国际包装展（interpack）上推出新一代装箱机。多功能全自动装箱机在中德合作江西德赛特包装机械设备有限公司诞生随着社会的不断进步，科技的快速发展，全自动装箱机也在不停的发展。本文着重介绍了全自动装箱机的工作原理，发展的概况以及其经常会产生的问题。关键词：全自动装箱机，双四连杆机构，抓瓶头，自动走箱台 The preliminary study of Automatic packing machine Qu Xiaoye 3030301002Department of mechanical manufacture 0301 School of mechanical engineeringAbstract: Aries Packaging, France Corporation was on the launch of a new generation of packing machine in the international packaging exhibition (interpack) in 2005 . Multifunction automatic packing machine was produced in which, Jiangxi Dorset Packaging Machinery Equipment Co. Ltd, with Sino-German cooperation . As society progresses, the rapid development of science and technology, automatic packing machines have been undergoing development. This paper introduces a fully automatic loading of the working principle, and an overview of the development, and its regular trembling .Key Words: Automatic packing machine，twin four linkage mechanism，,claw，the channel for transporting boxes引言：瓶装装箱是啤酒、饮料等包装的一道必要工序。全自动装箱机是为生产瓶装饮料(含酒类及其它各种饮料) 时，实现装箱自动化的专用设备，其装箱速度大约为每小时300箱以上,并且能和各种灌装机配套。(1)最常见的装箱机是由抓头充、排气来实现抓、放瓶子的。通过机械运转、气动和电控把瓶子准确、可靠地将瓶子放进箱子里。通过独特的四连杆机构，使瓶子提升和降落运动准确平稳。全自动装箱机的工作原理1.1装箱工作原理：（2） 1.1.1抓头从输瓶台上 抓住瓶子（横梁 在后位置，如图1） 1.1.2瓶子前移到输箱 带上方（横梁在 前位置，如图2） 1.1.3瓶子被放在箱子 里（横梁在最低 位置，如图3）1.2装箱过程的动作分解：整个装箱过程的动作可分解为三部分运动：瓶的运动；箱的运动；连接瓶箱的连杆机构带动的抓头运动。1.2.1瓶的运动： 在整线中，从灌瓶机来的灌好的瓶子被输送到待装箱工位。（3）在输运过程中，首先经过理瓶装置，分隔出的几条槽,每槽只能走一列瓶子，理瓶板前后移动，使得瓶子有序地经过理瓶板，分成一排一排地进入前面的导瓶板，到达导瓶板最前面的瓶子被挡瓶定位杆挡住，在抓头抓瓶的时候，挡瓶定位杆松开，于是抓头抓住瓶子向上运动。在这个过程中，输瓶带输瓶，瓶到位后输瓶带停止，等候抓头抓瓶。 图4 进瓶示意图（2）1.2.2箱的运动：自动走箱槽的功能是输送空箱到装箱工位,并把装满的箱子继续送到出口。（3）首先，空箱进入输箱带，通过这部分的挡箱装置，将箱分为四箱一组，然后进入输箱带，第五个箱子被挡在后面，而进入输箱带的四个箱子又被前面的挡箱臂挡住，同时分箱装置将这四个箱子分开定位，定位后的一组箱子停在输箱带上，抓着瓶子的抓头将瓶子准确地放在这一组箱子里。图5 输箱示意图（2）1.2.3 抓头部分的运动：由装箱机的主传动带动双四连杆机构，实现抓瓶装箱所需要的曲线运动，抓头部件装在头架部分，在主传动处于曲线的两个特征点上时，在输瓶带上抓头充气抓瓶，在输箱带上抓头放气放瓶。(4)机械手臂的动力采用电机,臂的升降采用双速电机,由电脑控制转换。这样既平稳又能快速准确到位。抓瓶头采用压缩空气鼓胀橡皮套箍紧瓶头来抓瓶,是软接触,不会损伤瓶子,抓得又牢放气即可放瓶,这样既快又可靠。抓头运动的在主传动曲线上依次为：（如图6） 在输瓶带上方，等待抓瓶； （空行程） 在抓瓶点，抓头充气抓瓶； （工作行程） 在输箱带上方，等待放瓶； （工作行程） 在放瓶点，抓头放气放瓶。 （工作行程）图6 抓瓶运动轨迹（2）综上所述，在装箱过程中，无论是瓶还是箱均经过有序的准备，分别排成一定的间距，与抓头的间距相同，使得抓头能够准确无误地抓瓶放瓶，完成装箱。全自动装箱机的发展概况如今，越来越多的人喜欢喝瓶装饮料，啤酒、橙汁、矿泉水，于是，对于饮料包装机械的要求越来越高了。从前，装箱机均是由人工控制，把走瓶台上的瓶子(如酒一箱20瓶)一次抓起来,装入走箱槽上的空箱内。这个工序虽然很简单,但是工人操作时,因速度很快,是一项繁重的体力劳动。一般工人只能连续工作一小时就要轮换休息,才能保持装箱速度。即使如此,平均每人每小时还只能装十多箱。由于是单调而繁重的劳动,很容易疲劳,打破瓶子的情况也是常事。按千分之一的损耗计算,一天装6000箱要损失6箱,一年按200d计算,约损失1200箱,实际损耗率可能要高得多。于是，现代的科技告诉我们要利用机械手。这不仅可以代替30多个强劳动力,而且损耗也可以大大减少。 如今，装箱机的种类很多，最常见要属YZBS-FZ系列和TM系列的产品。这些全自动的装箱机不仅工作可靠，运行平稳，生产效率高，而且操作容易，结构合理，安全可靠，符合卫生要求。 目前，中国最先进的多功能全自动装箱机诞生于江西德赛特包装机械设备有限公司。该机是由德赛特包装机械设备有限公司的一位德国著名专家研发而成。该机通过抓瓶器将瓶子自动装进纸（塑料）箱内，通过电气自动化控制使瓶子提升、移动、降落，动作协调，运行平稳准确、操作简单方便，本机采用变频调速及PLC控制技术，结合人机界面，自动化程度高。工作过程中，装箱运动由伺服驱动器和变频器控制的电机驱动，起步和终止均缓慢平稳，装箱速度采用变频器进行无级调速，生产效率极高，结构先进、灵活。产品由合理的机械结构，可靠的气动装置和先进的电控技术组成，更换不同瓶型生产时只需要更换夹瓶机构，是机械、气动、电控一体化的先进设备。产品采用现代显示技术-触摸屏，设备常见故障可自行分析、诊断，并排除。产品除了设置保护罩，还配备光电安全保护装置，当装箱过程中出现缺瓶、缺箱、堵箱、错位等现象时，能立即自动停机，保护机器。如今，一般的装箱机的整个装箱过程的动作基本可分解为三部分运动：瓶的运动；箱的运动；连接瓶箱的连杆机构带动的抓头运动。带动曲柄转动的主传动机构，减速电机直接套在转动轴上，然后用无键联接装置收缩盘把减速器与轴联结起来。收缩盘是靠拧紧高强度螺栓使包容面间产生的压力和摩擦力实现扭矩传递的，由于无键槽，轴的材料有效利用率高，对轴不产生机械损伤，可承受变载荷和冲击载荷，还具有过载保护等优点。采用带制动的电机，并采用变频器调速，主传动速度为双速，保证本机生产能力与整个生产线相匹配。要设计一套完整实用的装箱机，还要注意以下几点：工作可靠，运行平稳，生产效率高，操作容易，结构合理，安全可靠，符合卫生要求，全自动控制。因此，对其的设计是要多方面的。以后，随着科技水平的飞速发展，装瓶机的体积应不断的减小，而工作效率确要求迅速提高。全自动装箱机常出现的问题装箱机在运行过程中产生抖动是包装生产经常遇到的问题。装箱机抖动就是指吸头架在下落装箱时产生的抖动，它会使瓶子摇摆，当瓶子摆动时，就会使瓶子与导向架或胶箱碰刮，造成商标纸刮烂，甚至爆瓶，影响操作安全。装箱机运作过程中抖动的产生原因虽然比较复杂，但往往是由于传动零部件存在间隙和运动惯性冲击及设计不当造成的。现在，已经有了很多能很好解决这个问题的方法。结束语全自动装箱机是适用于饮料行业(含白酒、啤酒和各种瓶装饮料) 的自动灌装线上的设备,属机电一体化产品。它与自动灌装线中的洗瓶、灌装等其它设备构成一个自动化系统。自动装箱机的核心部分是自动装箱机械手。参考文献1 邹子良、刘晔、朱景环，全自动装箱机的研制(I)控制系统设计， 南昌大学学报(理科版)， 1997 Vol.21 No. 3.2 孙健，装箱机工作原理， Krones magazine（中文版），2005 Vol.4.3 邹文生、朱景环、刘晔，全自动装箱机的研制（II）自动趟瓶台和自动走箱槽的设计，南昌大学学报(理科版)，1998 Vol,22 No.34 邹文生、朱景环、刘晔，全自动装箱机的研制（）自动趟瓶台和自动走箱槽的设计，南昌大学学报(理科版)，1998 Vol,22 No.35 邹文生、刘晔、朱景环，全自动装箱机的研制(四)自动装箱机械手的设计，南昌大学学报(理科版)，1998 Vol.22 No. 36 何志坚，进口曲柄四杆机构型装箱机抖动问题的改进，包装与食品机械，2005 Vol.23 No.5.7 krones备件手册8 蒲良贵、纪名刚，机械设计（第七版），高等教育出版社，20019 ehert ,packing machine in China,Krones magazines,2005 vol.410Making the case for lead screws,.Machine Design, 10/26/2006, Vol. 78 Issue 20, pS1-S1, 1p草图中CAD模型的发展：汽车应用方面专题研究机械工程学院 机制0301 3030301002 瞿筱烨摘要：今天的产品设计不仅仅要考虑他们的功能需求，还要考虑到美感问题。在汽车制造业，class-A曲面成为了外观设计过程中的一大重要部分。Class-A曲面是连续曲度的自由形态表面。设计所有组成部分或系统的过程，是通过引起实际上描述的产品的形式、作用和适合的概念开始。概念草图帮助设计师迅速和容易地到达一个令人满意的能为详细设计所指定的阶段。这些概念草图可以为对曲线和曲面的数字式构思设计和分析的发展所使用。例如Alias等的软件可以被用于汽车外观的设计。本文介绍了一个从手工绘制概念图到Class-A曲面形成的系统方法。这些图象的处理我们用CATIA V5追踪者模块。 设计师能使用不增加任何特别硬件的CATIA V5软件追踪模块来参考使用数字式草图。然后，试图改进这些曲面的美感。这个方法能用来改进CATIA V5用户的设计实践和技能。关键词： 概念草图，黏土塑造，Class-A曲面，反射线一介绍 产品外观为产品本身带来了视觉冲击。因为，外观是无需改变产品技术表现而增加了价值的一个重要方式。当新产品质量相差不大的时候，外观就因此成为了吸引消费者的一个十分重要的因素。外观的设计观念并不是一成不变的，而是新鲜的，令人兴奋的。开发设计新的外观花样为顾客提供了视觉上的冲击。如今，产品的设计不但要考虑到其功能的使用，而且还应特别考虑它带给人的视觉上的美感，以促进人们对其的购买欲。这就是Class-A曲面变得越来越重要的原因。Class-A曲面给我们带来美观形状和高质量表面的自由形态曲面。在汽车制造业，现有的产品经常改变其款式，因为相比产品自身的演变，工程师们更加喜欢对其进行完整的重新设计。用户的反映和建议，市场的方针都将影响产品的设计和应作的改变。然而，产品的修改总是比重新开发一个新产品要便宜得多。为了提高模型的视觉冲击，一辆传统汽车的发展中必将包含很多手工绘制草图的发展。这些草图，一些被选择并制作成以1：10缩小的粘土模型。当一个按一定比例制作的粘土模型完成后，通过三维扫描器进行扫描。之后，一个1：1制作的模型被开发出来了。在这个阶段，所有的改变都需要很长的时间。传统方法和计算机辅助制图设计出的外观的概念草图的比较可参见图1。 这项工作的主要在于运用CATIA V5软件完善CAD模型的表面曲线度。试图比较经过和未经过检查的表面曲度连续性的外观美感度。我们发现，尽管两者运用同一款软件，但是仍然很难辨识出表面有间断的表面。CATIA V5用户采用这种程序来提高他们的创新。艺术家绘制的草图被运用在了这个程序中。这看来是一个新颖的方式。以过去的经验作者发现CATIA V5的兼容性对表面检查有一定的限定。二文献历史很多文献有很多关于产业实践和表面修复技术的调查研究。托维1讨论过汽车的草图和概念设计。汽车设计者运用草图来支持他的第二阶段的构思设计和发展。运用计算机辅助设计，即CAD来设计正逐步体现出它的重要性。托维2还曾描述过，示意图映射作为工具与常规从模型映射相比较更具有局限性。同时，他也给出了一个摘要，描述从示意图到直接的模型的发展。这个概念设计方法同样也被讨论。SuBneretal.3曾讨论运用镜面反射来调整汽车的表面的质量。一个有着非常真实的外形的模型被安放在一间照射着平行光线的屋子里。这些光线的反射就是非常好的测量表面质量的工具。即如测量表面的间断曲率和形状的特性等等。哈根4介绍表面检查的细部测量方法。三圆法被用来测量凸出。焦曲面是一种新的测量自由形态的曲面和外形的工具，是在把资料传输给电脑数值控制机器前分析表面质量的一些特殊线的集合。哈曼5给出了一个检查表面的概括方法，其中包括反射光线，等幅透线，弯曲块，加亮光线和等值线。这些工具大体都是用在电脑图像上和在CAD上分析自由形态曲面。哲赛尔6说等辐透线和反射光线是两种不同的检测表面的工具。等辐透线经常用来识别曲面间的连贯性，而反射光线则经常用来测量表面的质量。莫纳7讨论了运用虚拟现实软件来减少间断时间和传达花费时间的发展过程。虚拟现实能够帮助改变实现从手工方式到数字环境下的初步概念草图的绘制方法。运用虚拟现实，设计师能够以一种更好的方式以数字化形象出新的花样。拜陇8解释了从传统花样方式到以CAD为基础的花样方式的革新的需要，以及演说了按照传统设计花样的方法的困难之处。三车型的花样对汽车外形的研究是因为对于消费者，车型的设计给与了他第一印象。在市场的竞争中，不仅仅是要有一个完美的设计，至关紧要的是在制造汽车时要让这个完美的设计方针正确的实现。传统汽车制作发展过程中的一个不好之处就是时间带来的变化和制作出的新产品的泥塑模型起不了什么作用。因为作为概念模型只是能够直观的看出最终的设计方案。然而要想改变这个最终模型是比较困难的。如图2所示，解释了如何基于CAD运用CATIA V5来设计汽车外形的一个方法，以及每一步的程序。3.1 概念草图的输入草图就是概念的发展的输入。概念草图帮助设计师快速并且简单的达到一个令人满意的能成为详细设计的设计阶段。草图被输入进CATIA V5追踪者模块。他们依次排列，比如说汽车的正视图取决于前面。同样的，汽车的所有视图都对应着一个面。所谓的草图就是由这些视图组成的一个长方形，模型就放在里面。图3展示了运用了手工准备的概念草图的扫描图像输入CAITA V5中。3.2 曲线的追踪与转化 在草图上挑选和画出曲线，经由这些曲线描绘出两张草图。所有的曲线都将取决于草图上相应的面。在描绘曲线时，交集法被用于产生曲线，所有的曲线都延伸或分割以便最终形成留下的曲线都是必需的。在所有的这三张图中，如果三张草图中表示同一条曲线，在一张视图上就会被分割成一些点，另外两张视图上提及的相应点就会被转换。如图4所示，一组曲线的产生使得勾勒出了一个个相应的面，这些面又组成了一张草图。3.3 曲线分析检查好的曲线能够让最终绘制出好的曲面。因此，在绘制出表面前，要先好好的分析曲线的质量。运用CATIA V5曲线分析能够检查曲线间的平滑的连接度。假如曲率变化平滑那么这些曲线将会形成光滑的曲面。但是，假如它不平滑，控制点描绘出的曲线将会被转化，于是曲率也将平滑的改变。图5描绘了曲率的不规律变化。图6则显示了曲率的平滑变化。每一个弯曲部分都展示了曲率的范围的最大化的变化。当很多的小点慢慢变小，这就显示了曲线上的平坦区域。这些点必需很平坦，否则，这些曲线就会出现顶点或者谷点。这也用在分析曲线间的连贯性。曲率的连贯性十分的重要，它将使的整个曲面没有平面。3.4 表面的产生与变化 曲线结合成面，这些面组合成了整个大表面。图7展示了用CATIA V5制作出来的概念模型。因为改变了花式，被描绘成特殊部分汽车的表面，（例如，车篷和车顶就被分割成了不同的部分），被分开放置在车身。 图8和图9展示了一些在研究中产生的不同外形。3.5 曲面检测为了达到A等级的表面质量，一定要进行曲面检测。等辐透线和反射光线是两种最常用的曲面检测的工具。等辐透线用来识别两个面之间的间断处。当光线从表面反射回来，加亮的地方通常反应了曲面的形状或形态。这些反射光线告知了用户哪里是曲率的分割处。这些反射线有个共同点就是本质反映，流线型，均匀。它被用来识别曲率的分断处和查找曲面的凹断处。曲率分断处用不连续的高亮区域表示。图10所示为模型上的等幅透线分布。高亮区域集中处反映了凹断处。图11，在曲面凹断处的等辐透线的分布情况。而反射光线经常被用来测量曲面质量。当进行反射时，会有一系列的平行线出像在曲面的光照平面上。图12所示了汽车表面上的反射线区域。3.6 演示模型演示是为了更好更清楚的呈现模型的外表。现实中的模型主要是为了使使消费者更加喜欢赏识我们的最终模型。一个VA环境用来清楚地呈现和现实演示。图13为由CATIA V5制作出的模型演示。四结论这篇论文试图提供一个运用CATIA V5软件辅助设计手工准备概念草图的系统方法。它亦检测揭露两个曲面间确实存在间断。如果按照惯例设计表面时，曲率的连续性并不尽人意，那么表面将有间断处，美感也将需要进一步提高。对于需要Class-A表面的设计发展来说这是一个有用的好方法。CATIA V5的用户能够在他们的时间中实现一些技术，而不需要增加什么贵重的硬件。参考文献1 Tovey, M. J., Newman, R. M., and Porter, S. Sketching, concept development and automotive design. Des.Stud.,2003, 24, 135153.2 Tovey, M. J. Concept designs CAD for the automotive Industry. J. Engng Des., 2002, 13, 513.3 Subner, G., Greiner, G., and Augustiniack, S.Interactive examination of surface quality on car bodies. Computer Aided Des., 2004, 36, 425436.4 Hagen, H., Hahmann, S., Schreiber, T., Nakajima, Y.,Wordenweber, B., and Hollemann-Grundstedt, P.Surface interrogation algorithms. IEEE Computer Graphics Applic., 1992, 12(5), 5360.5 Hahmann, S. Visualization techniques for surface analysis. In Advanced visualization techniques (Ed.C. Bajaj), 1999, pp. 126 (John Wiley, New York).6 Theisel, H. Are isophotes and reflection lines the same? Computer Aided Geometric Des., 2001, 18,711722.7 Monacelli, G. VR applications for reducing time and cost of vehicle development process. In Proceedings of the Eighth International Conference ATA on Vehicle Architectures: Products, Processes and Future Developments, Florence, Italy, May 2003 (Eurographics Association, Switzerland).8 Barone, M. The process improvement impact on the styling workflow of an industrial design company. In Proceedings of the EUROGRAPHICS Workshop on Sketch-Based Interfaces and Modeling, 2004.41Development of CAD models from sketches:a case study for automotive applicationsR Vignesh, R Suganthan, and K Prakasan*Department of Production Engineering, PSG College of Technology, Peelamedu, Coimbatore, IndiaThe manuscript was received on 6 April 2006 and was accepted after revision for publication on 2 August 2006.DOI: 10.1243/09544070JAUTO331Abstract:Today products are designed not only for their functional requirements but also foraesthetics. In the automotive industries, styling has become a major part of the designprocess with class-A surfaces. Class-A surfaces are freeform surfaces with a continuouscurvature. The process of engineering any component or system begins by generating a conceptthat actually describes the product in terms of its form, function, and fit. Concept sketcheshelp the designers to arrive quickly and easily at a stage where a satisfactory design can bespecified for detailed design. These concept sketches can be used for development of the digitalconcept design and analysis of the curves and surfaces. Software such as Alias exists and thuscan be used with suitable hardware for sketching the concept of the car body on a computerscreen. In this paper a systematic procedure is discussed for generating class-A surfaces fromthe images of concept sketches which are manually prepared on paper. These images areimported into the sketch tracer module of CATIA V5. A designer can use the image as thereference and produce a digital sketch by tracing the image using CATIA V5 software withoutadding any special hardware. Later, interrogation of these surfaces for improved aesthetics canbe attempted. This method will be useful for the users of CATIA V5 to improve their designpractices and skills.Keywords:concept sketches, clay modelling, class-A surface, reflection lines, isophotes1INTRODUCTIONreason for the evolution of class-A surfaces and theirimportance. Class-A surfaces are those aesthetic free-Productstyling iscarriedout tocreatevisualform surfaces that are visible to us and that have anattractiveness in products. Styling is widely acceptedoptimal aesthetic shape and high surface quality.as an important way to add value to a productRestyling of existing products is frequently per-without changing its technical performance.formed in the automotive industries, since engineersAs new product quality rankings converge, stylingusually prefer the evolution of a product to a com-is emerging as a key differentiator for consumers.plete redesign. Customer feedback, client assistanceThe role of styling is to create fresh and excitingsuggestions, and market directives usually influencedesign concepts that are not just contemporary butthe decision on redesign or restyling of a product.trend setting as well. Styling enhances the visualHowever, quite often product modifications are lessappeal of the vehicles and at the same time developsexpensive than the development of a new product.innovative designs and components for customers.A traditional car development process involves theToday, not only are products designed consideringdevelopment of many handmade rendering sketchesthe functionality but also special considerations arein order to offer a vision of the models look. Fromgiven to their aesthetics which can produce a desirethese sketches, a few are selected and, by pasting thein a persons mind to own that product. This is thefour views of a constrained drawing on the wall,which are made on a 1:10 scale, the scaled-downclay model is developed. One scaled-down clay* Corresponding author: Department of Production Engineering,model is finalized and the model is scanned usingPSG College of Technology, Peelamedu, Coimbatore, Tamil Nadu,641 004, India. email: prakasan_psgrediffthree-dimensional scanners. Then a 1:1 clay modelJAUTO331 IMechE 2007Proc. IMechE Vol. 221 Part D: J. Automobile Engineering42R Vignesh, R Suganthan, and K Prakasanof the finalized sketch is developed. In this phaseto be a novel approach. From the experience of theall the changes require much time. A comparisonpresent authors it was found that awareness ofbetween concept development and styling by thethe capability of CATIA V5 for surface interrogationconventional method and the approach based onis limited among puter aided design (CAD) is provided in Fig. 1.The objective of this work is to present a case inwhich the images of manually prepared conceptual2LITERATURE REVIEWsketches are used in CATIA V5 software to trace thecurves for developing CAD models and surfaceTo determine the industry practices and surfaceinterrogation. An attempt is also made to compare ainterrogation techniques for styling, a literaturesurface that is not checked for curvature continuityreview was carried out and the relevant observationsand a surface checked for curvature continuity forare presented here.their aesthetics and appearance. The approach usedTovey 1 discussed sketching and its role inhere can reveal the discontinuity in the surface whichthe concept design of automotives. Automotiveis difficult to notice otherwise although both aredesigners use sketches to support the styling activitycreated in the same software. The procedure adoptedthrough its two phases of concept design and designhere can be practised by the users of CATIA V5 todevelopment before handing over to the downstreamimprove their innovations. A sketch on paper by andevelopment processes. The importance of computerartist is made use of in this procedure. This appearsaided styling over CAD is highlighted.Tovey 2 described the work on sketch mappingas a usable tool and contrasted it with the more con-ventional direct modelling approach which is seento have limitations. He also gave a brief descriptionof work in progress on deriving forms directly fromsketches. The concept design methodology was alsodiscussed.Suner et al. 3 discussed the use of reflectionlines and specular highlights for the quality controlof car body surfaces. A prototype with a highlyreflective surface was built and viewed in a cubingroom, which has many parallel arranged lights.The reflections of the lights are a good measure forsurface quality, i.e. for detecting surface curvaturediscontinuities and for discussing the character ofthe shape.Hagen et al. 4 presented a detailed survey ofsurface interrogation methods. Orthotomics are usedfor convexity tests. Focal surfaces, a new tool foranalysing freeform curves and surfaces, are specialline congruences that are used to analyse the qualityof the surface before sending the data to CNCmachines.Hahmann 5 gave a general method for surfaceinterrogation which includes reflection lines, iso-photes, curvature plots, highlight lines, and isolines.These tools are mainly used in computer graphicsand found application in analysing freeform surfacesin CAD.Theisel 6 showed that isophotes and reflectionlines are different tools for surface interrogation.Isophotes were used to identify curvature dis-continuities between surfaces, and reflection linesFig. 1Concept development and styling: (a) con-ventional method and (b) CAD-based approachwere used to measure the quality of the surface.JAUTO331 IMechE 2007Proc. IMechE Vol. 221 Part D: J. Automobile Engineering43Development of CAD models from sketchesMonacelli 7 discussed the virtual reality (VR)3STYLING OF A CAR BODYapplications for reducing the time and cost involvedin the vehicle development process. VR can help toA study was carried out on the styling of automotiveexteriors because the first impression that a customerchange the initial concept sketching from a manualmethod to a digital environment. VR has applicationshas of a car is the design of the car body. To be com-petitive in the market, not only is it necessary to havein styling and the designer can visualize the digitalmodel in a better way.a good design but also it is crucial that the stylistsguidelines will be accurately implemented whenBarone 8 explained the need for renovating thetraditional styling process to a CAD-based stylingbuilding the car.The disadvantages with the traditional car develop-process and addressed the difficulties faced duringthe traditional styling process.ment process are the time taken to make changesand the inability of the clay model to create variantsof the new product. As the concept model can beseen only at the final stage of the design process,making changes to the concept model in the finalstages is difficult.The methodology adopted and the step-by-stepprocedure of the CAD-based development processfor the car body using CATIA V5 are explained inFig. 2.3.1Importing concept sketchesThe input for concept development is sketches.Concept sketches help the designers to arrive quicklyand easily at a stage where a satisfactory designcan be specified for development of detailed design.The sketches are imported into the sketch tracermodule of CATIA V5. They are aligned such that thefront view of the car will lie on the front plane.Similarly all the views of the car are aligned to lie onthe corresponding plane. The sketches will form abounding box and the model will lie within thebounding box. Figure 3 shows the aligned conceptsketches imported into CATIA V5 using the imagesFig. 2Methodology for CAD-based concept develop-ment and styling(scanned) of manually prepared concept sketches.Fig. 3Concept sketches imported into CATIA V5JAUTO331 IMechE 2007Proc. IMechE Vol. 221 Part D: J. Automobile Engineering44R Vignesh, R Suganthan, and K Prakasan3.2Tracing and translating curvesThe generated sketches are mirrored to generate agroup of curves as shown in Fig. 4, which are suitableTwo sketches that will best represent the curve to befor generating patches.generated are selected and curves are traced abovethe sketch. Both curves will lie on the corresponding3.3Curve interrogationplane of sketch. To generate a single curve from thecurves traced, an intersection technique is used;Good curves will result in good surfaces. Therefore,before generating surfaces the curves are analysedthe curves traced are extruded and intersected sothat the resulting curve will be the required curve forfor their quality. Porcupine curvature analysis inCATIA V5 checks for a smooth variation in curvaturesurface generation.If all three sketches represent a curve, then points(plots) throughout the curve. If the curvature vari-ation is smooth, then the curves will result in smoothare plotted in one view and with the other twosketches as references the points are translatedsurfaces. If it is not smooth, then the control pointsrepresenting the curves are translated so that asuch that the points will appear to lie on all threesketches.smooth variation in curvature is obtained. Figure 5Fig. 4Curves for patch generationFig. 5Irregular variations in curvatureJAUTO331 IMechE 2007Proc. IMechE Vol. 221 Part D: J. Automobile Engineering45Development of CAD models from sketchesFig. 6Smooth variations in curvaturerepresents an irregular variation in curvature andtude of the spikes is small, this indicates a flat regionFig. 6 shows a smooth variation in curvature. Theon the curve. The magnitude must vary smoothly, orcurvature comb plot will show variation in the mag-the curve will have sudden peaks and valleys. This isnitude of the radius of curvature. When the magni-also useful in analysing the continuity between thecurves. For curvature continuity it is necessary thatthere is no step in the curvature comb.3.4Generating surfaces and variantsSurfaces are generated from the curves as patches.Figure 7 shows the concept model generated inCATIA V5. The surfaces representing a particularcomponent in a car (e.g. the hood and the top areseparate components) are placed in separate openbodies because of the ease in restyling. Figures 8and 9 show some of the variants generated duringFig. 7Concept modelthe present study.Fig. 8Variant: glass topFig. 9Variant: convertible topJAUTO331 IMechE 2007Proc. IMechE Vol. 221 Part D: J. Automobile Engineering46R Vignesh, R Suganthan, and K Prakasan3.5Surface interrogationSurfaces are interrogated for class-A quality. Isophotesand reflection lines are the most commonly usedtools for surface interrogation. Isophotes are usedto identify the discontinuity between surfaces. Theyhighlight the behaviour of the form or shape of asurface when light reflects from the surface. Thisreflection of light gives the user an understandingabout the curvature discontinuity. This reflectionshould be natural and streamlined and shouldhave uniformity. It is used to identify curvaturediscontinuities and to locate the dents in surfaces.Fig. 10Isophote plotCurvature discontinuities are represented by dis-continuous highlight plots. Figure 10 shows theisophote plot of one of the models. Dents arerepresented by convergence of the highlight plot atthe point of dent. Figure 11 shows the isophote ploton a dent on the surface. Reflection lines are used tomeasu