拉钩的冷冲压模具设计【含CAD图纸、说明书】
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毕业论文(设计)任务书题目:冷冲模设计拉钩专业班级: 学生姓名: 学号 一、主要任务与目标:图1为某电器元件拉钩。该零件的制造方法为冷冲压成型,本课题要求分析封盖冲压件的成形工艺,设计模具,画出模具装配图及所有零部件的工程图,写出毕业论文。图1 拉钩二、主要内容与基本要求:(1)分析垫片的冲压成形工艺。(2)模具设计。此零件厚度小,形状简单,要求设计的模具具有高精度和高成型效率。(3)打印图纸,写出毕业论文。(4)要求学生熟悉冷冲模具设计工艺,具有较强的机械设计能力。设计图纸的正确与否是评定本次设计水平的关键。三、计划进度:2007.12.202008.2.24 文献检索,外文文献翻译,写出开题报告。2008.2.252008.5.10 冲压成形工艺分析,模具设计。2008.5.112008.5.20 整理图纸,写出毕业论文。2008.5.212008.5.31 完成毕业论文,毕业答辩。推荐参考文献:1、冷冲压模具设计与制造手册。 2、冷冲模图册。3、冲压工艺学4、材料成型技术5、模具计算机辅助设计指导教师 年 月 日专业负责人: 年 月 日 6 毕业论文(设计)文献综述题目:拉钩的冷冲模设计 系 别: 专 业:机械设计制造及其自动化班 级: 学 号: 学生姓名: 一、模具工业的分类我国模具设计与制造技术的发展经历了手工作坊制造阶段、工业化生产阶段和现代化生产阶段。伴随着计算机技术的快速发展, 数字化、信息化CADCAE/CAM技术和数控加工机床已普遍采用, 模具产业正处于高速发展阶段。模具是制造业的重要基础工艺装备。模具总体上可分为两大类: 金属材料制件成形模具,如冲压模具、锻造模具、压铸模具、挤压模具、拉丝模具、粉末冶金模具等; 非金属材料制件成形模具, 如塑料注射模具、压铸模具、挤出模具, 橡胶制件、玻璃制件和陶瓷制件成形模具等。模具的具体分类方法很多, 如按模具结构形式分, 冲压模具可分为简单模、连续模和复合模, 注塑模具可分为单分型面和双分型面注塑模具等; 按工艺性质分, 冲压模具可分为冲孔模、落料模、拉深模、弯曲模,塑模具可分为压塑模、传递模、注射模等。1其中冲压模具、塑料模具、铸造模具、锻压模具、橡胶模具、粉末冶金模具、拉丝模具、无机材料成形模具等是最主要的八大类, 用于制造业中的几乎所有产品的生产。7二、模具工业的地位模具是以其特定的形状通过一定的方式使原材料成型。随着社会的发展和科技的进步, 模具行业越来越被重视,模具技术在国民经济各个部门都得到广泛的应用,它不仅与整个机械行业密切相关,而且与人们的生活密切相关。模具工业是国民经济的基础产业,是“百业之母”,是永不衰亡的行业,模具工业的发展水平标志着一个国家的工业水平及产品开发的能力。“十五” 规划指出,模具是生产各种工业产品的重要基础工艺装备,国民经济的五大支柱产业机械、电子、汽车、石化、建筑等都要求模具工业的发展与之相适应。模具因其生产效率高、产品质量好、材料消耗低、操作简单、生产过程易于实现机械化与自动化、生产成本低而获得广泛应用,利用模具可以加工出薄壁、重量轻、刚性好、形状复杂的零件;产品质量有模具保证,具有一模一样的的特点;这是其它加工制造业所无法完成的;模具是现代工业,特别是汽车、摩托车、航空、仪表、仪器、医疗器械、电子通信、兵器、家用电器、五金工具、日用品等工业必不可少的工艺装备。据资料统计,利用模具制造的零件数量,在飞机、汽车、摩托车、拖拉机、电机、电器、仪器仪表等机电产品中占80%以上;在电脑、电视机、摄像机、照相机、录像机等电子产品中占85%以上;在电冰箱、洗衣机、空调、电风扇、自行车、手表等轻工业产品中占90%以上;在子弹、枪支等兵器产品中占95%以上;在日用金属产品中占95%以上。可见,研究和发展模具技术,对于促进国民经济的发展具有特别重要的意义。目前,模具技术已成为衡量一个国家产品制造水平的重要标志之一。2起步到现在,我国模具工业经历了半个多世纪的发展,已有了较大的提高,与国外的差距正在进一步缩小。而中国模具对世界的影响也在不断扩大, 主要表现在以下几点:1、ISTMA 和FADMA 及其他国家的模协和有关国际组织已越来越重视中国模协, 他们邀请中国模协出席国际会议和参加国际行业活动越来越多, 他们到中国来考察和交流也越来越多, 中国模具已经成为国际模具中的一个不可忽视的力量。2、随着国际交往的日益增多和外资(包括港资、合资) 在中国模具行业的投入日渐增加, 中国模具正表现得越来越融入世界, 并已逐步与国际接轨, 三资企业已对中国模具的发展作出了很大贡献,中国模具和世界模具已越来越密不可分。3、无论是出口还是在中国国内使用, 中国模具已经为境外企业和境内三资企业降低了不少生产成本, 也就是说, 为世界的进步做出了一些贡献,而且这一贡献将随着中国模具的进一步发展而不断增大。中国模具与世界正在实现共赢。4、由于中国的过去、现在和不久的将来一直有较为优秀且丰富和廉价的人力资源、庞大的市场及其他许多有利条件, 外资在中国模具中已经并且将进一步占据越来越重要的地位, 中国已成为承接工业发达国家模具业转移的良好目的地, 确实加速了世界模具产业的转移, 从而也为通过这种转移而使工业发达国家向更高层次发展做出了贡献。5、中国庞大的模具市场促进了世界模具的发展。从上述情况来看, 中国模具确实已经与世界模具密不可分, 而且中国模具在世界模具中的地位将会越来越重要, 其影响也会越来越大。中国模具加速融入世界并实现国际共赢的局面将会进一步发展下去。在当今的信息社会和世界经济进一步全球化的发展过程中,世界在促进中国模具的发展,中国模具也正在并将进一步促进世界的发展。9三、我国模具工业的现状模具属于边缘科学,它涉及机械设计制造、塑性加工、铸造、金属材料及其热处理、高分子材料、金属物理、凝固理论、粉末冶金、塑料、橡胶、玻璃等诸多学科、领域和行业。从中国模具工业协会获悉, 近年来在国民经济中占有重要地位的模具工业得到了迅速发展。模具是工业生产的基础工艺装备在电子、汽车、电机电器、仪表、家电和通讯等产品中, 一般的零部件都依靠模具成型。国民经济的五大支柱产业, 机械, 电子、汽车、石化、建筑都要求模具工业的发展与之相适应, 模具是“ 效益放大器”, 用模具生产的最终产品价值, 往往是模具自身价值的几十倍、上百倍。模具生产水平的高低, 己成为衡量一个国家产品制造水平高低的重要标志, 在很大程度上决定着产品的质量、效益和新产品的开发能力。因此, 振兴和发展我国的模具工业,日益受到人们的重视和关注国务院颁布的关于当前产业政策要点的丸定也把模具列为机械工业改造序列的第一位、生产和基本建设序列的第二位。由于我国模具工业发展迅速, 前景广阔, 国内外模具及模具加工设备厂商已普遍看好中国市场。纵观我国的模具工业,既有高速发展的良好势头,又存在精度低、结构欠合理、寿命短等一系列不足,无法满足整个工业迅速发展的迫切要求。3 近年来,我国模具工业的迅速发展是大家有目共睹的,中国模具工业的现状大致可以从以下3个方面来讲:1、模具的产值与出口量增长明显。从整体情况来看,我国已经步入模具工业大国之列,但是距模具强国还有相当差距。2、模具制造水平不断提高。近几年,以大型、精密、复杂、长寿命模具为代表的、技术含量较高的中高档模具的比重进一步提高,现在中高档模具所占比重已经达到35% 以上。模具的设计和制造水平也有了很大的发展,很多先进的模具设计与制造技术在我国的模具企业中得到应用,如CAD/CAE/CAM 等计算机辅助技术、高速加工技术、热流道技术、气辅技术、逆向工程等新技术得到广泛应用,E R P、P D M 等信息化管理技术正得到积极推广,这些先进技术的应用和信息化管理的实施极大地提高了模具企业的生产效率,缩短了生产周期。3、我国模具行业已经形成了自己的骨干队伍。目前,我国约有模具生产厂点3 万余家,从业人员100余万人,在各个模具行业的骨干企业队伍中也涌现出了本行业的龙头企业。他们的生产装备先进,生产达到了一定规模,技术水平较高,而且产品具有自己的特点。10目前,中国约有模具生产厂2万余家,从业人员50多万人,全年模具产值达450亿元人民币以上。近年来,模具行业结构调整步伐加快,主要表现为大型、精密、复杂、长寿命模具和模具标准件发展速度高于行业的总体发展速度;塑料模和压铸模比例增大;面向市场的专业模具厂家数量及能力增加较快。随着经济体制改革的不断深入,“三资”及民营企业的发展很快。5在模具产值产量和进出口迅速发展的同时, 近年来中国在模具行业技术进步和模具水平的提高方面也取得了可喜的成绩。现在, 我国已能生产精度达到详的多工位级进模, 寿命可达亿冲次以上。个别企业生产的多工位级进模已可在次的高速冲床上使用, 精度可达林。在大型塑料模具方面, 我国已能生产英寸大屏幕彩电和英寸背投式电视的塑壳模具、大容量洗衣机全套塑料件模具以及汽车保险杠、整体仪表板塑料模具等。在精密塑料模具方面, 我国已能生产照相机和手机塑料件模具、多型腔小模数齿轮模具及精度达林的腔塑封模具等,精度达到林的光盘模也已能够生产了。塑料模具的热流道和气辅等技术水平不断提高。在大型精密复杂压铸模方面, 国内已能生产自动扶梯整体踏板压铸模、汽车后桥齿轮箱压铸模以及汽车发动机壳体的铸造模具等。在汽车覆盖件模具方面,国内已能生产中档新型轿车的覆盖件模具, 高档轿车的部分覆盖件模具也已能够生产了。子午线轮胎活络模具、铝合金和塑料门窗异型材挤出成形模、精铸或树脂快速成型拉延模等, 也已达到相当高的水平, 制造出来的模具可与进口模具媲美。国内生产的最大模具单套重量已超过100t我国模具企业CAD、CAM、CAE、CAPP、PDM、PLM、ERP等数字、化信息化技术的使用面正在不断扩大, 水平也在不断提高。中国模具工业产值仅次于日本和美国, 排在世界前三位。中国经济的高速发展同样对模具工业提出了越来越高的要求, 也为其发展提供了巨大的空间。现今, 国内的模具生产厂家已增至2 万余家, 模具制造从业人员已超过50 多万人, 模具的年产值达到534 亿元人民币。近10 年来, 国内模具在数量、质量、技术等方面有了很大的跨跃; 现正以每年15 %左右的增长速度稳步发展。4四、现代模具设计与制造方法 现代模具制造业已成为技术密集型和资金密集型的产业, 它与高新技术已形成相互依托的关系。一方面, 模具是直接为高新技术产业化服务的不可缺少的装备另一方面, 模具生产本身又大量采用高新技术及装备, 因此, 模具制造已成为高新技术产业的重要组成部分。模具成形零件时实现快速、优质、低耗是国家可持续发展战略的要求。7我国模具制造技术发展迅速,逐渐由单一、具体、细节的设计及各道工序的加工过程向设计、制造技术的系统化、集成化过程转变,已成为现代先进制造技术的重要组成部分。1、模具CAD/CAE/CAM技术:以三维造型为主的模具设计、制造、工艺信息的数字化传递及转换所形成的CAD/CAE/CAM一体化技术在我国已大量推广应用。例如,汽车大型覆盖件模具已普遍应用CAD/CAM技术,实现了模具设计、制造、冲压一体化、数控编程和数控加工实现了DNC,计算机软硬件配置已接近国际水平;在塑料模具方面也已广泛应用CAD/CAE/CAM技术,多项国内自主开发的软件推广之中,如北航华正的CAXA软件系列和华中理工大学的HSC2.0等;在压铸模方面,CAD/CAM同样得到了广泛应用,并已开始应用CAE软件进行浇道系统和工艺参数等方面的优化分析。2、模具先进制造工艺及装备:模具由功能件和支持件组成。在塑料模和压铸模中,功能件为型腔和型芯,在锻模中为型腔,在冲压模具中为型孔和冲头,支持件一般为标准件,因此,模具加工的主要部件可分为两类,即型腔,型芯加工和型孔加工。(1)高速铣削加工高速铣削加工在模具制造中具有以下特点:高效,高速铣削加工的主轴转速一般为15000-40000r/min,最高可达100000r/min。切削钢时,其切削速度约为400m/min,比传统的铣削加工高510倍;在加工型腔模时与传统的加工方法相比起效率提高4-5倍;与完全采用EDM加工相比,其加工速度提高了4-8倍;高精度,一般加工精度为10m,有的精度更高;高表面质量,由于高速铣削的工具温度小,姑表面没有变质层及微裂纹,热变形也小。最好的表面粗糙度R小于1m;可加工高硬材料,可铣削5054HRC。(2)NCEDM加工NCEDM的多轴联动控制、电极自动交换、C轴加工、数控摆动等功能能完成各种复杂型腔的精密加工,采用自适应控制、模糊控制、各种专家系统、新型脉冲电源灯优化加工状态,自动完成全部加工过程。NCEDM在中小型腔模、复杂精密型腔模等加工方面发挥着越来越重要的作用。(3)虚拟轴数控加工在模具复杂型腔铣削加工中采用五轴数控铣床可提高加工质量和效率。五轴数控加工还可在三轴联动加工不易接近的地方进行加工,以避免铣刀中心铣削工作带来的弊端,并能在一次装夹中完成五面加工,因此更适合于模具制造。虚拟轴五轴数控机床突破了传统的串联式床身滑台结构,由于采用了高级软件、降低了传统五轴数控铣床结构的复杂性,因此,结构简单,成本低。虚拟轴五轴数控机床也可实现高速加工,尤其适合复杂型腔的铣削、磨削和测量,是我国模具制造工艺及装备的重要发展方向。(4)复合加工复合加工时指在一台机床上进行两种或两种以上不同加工工艺的复合,以实现不同加工工艺优势互补的作用。其发展方向又可分为两个方向:铣削加工与激光加工复合技术,铣削加工与EDM复合技术。(5)型孔加工工艺及装备 冲压模等型孔加工主要依靠磨削加工及数控电火花线切割加工(WEDM)。在磨削加工中,成形磨、坐标磨、光曲磨等精密加工工艺及装备在我国已广泛应用。WEDM在冲压模等型孔加工中已起到不可替代的作用。国内外冲压模等加工都离不开WEDM。主要方向有:磨削加工、WEDM加工。6五、我国模具行业存在的问题目前, 我国模具总量虽然已达到相当大的规模, 模具水平也已有了很大提高, 但在总体上, 我国模具生产的商品化、专业化、标淮化程度还较低, 商品化模具只占左右, 模具标准件使用覆盖率还不到, 专业模具企业只占模具生产厂点的少数, 而且装备也比较落后。由于资金缺乏, 我国的模具企业大都只能购买较低档的国产设备和来自我国台湾的设备, 而少用欧美和日本的高档设备, 设备数控化程度远低于国际水平。我国模具设计制造水平在总体上要比工业发达国家落后许多。主要存在以下几点问题:1、产品质量不高:当前我国模具生产厂中多数是“大而全”、“小而全”,国外模具企业大多是“小而专”、“小而精”。国内模具总量中属大型、精密、复杂、长寿命模具的比例只有30% 左右,国外在50%以上。国内模具生产厂家,工艺条件参差不齐,差距很大。现代模具工业早已走出以前手工制模的时代,进入了数字化时代,实现了无图化生产,通过电脑输入数据加工制作模具。我国不少厂家由于设备不配套很多工作依赖手工完成,严重影响了精度和质量。2、标准化水平不高:模具是专用成形工具产品,虽然个性化强,但也是工业产品,所以标准化工作十分重要。模具标准化工作主要包括模具技术标准的制订和执行、模具标准件的生产和应用以及有关标准的宣传、贯彻和推广等工作。中国模具标准化工作起步较晚,因此模具标准化落后于生产,更落后于世界上许多工业发达的国家。由于中国模具标准化工作起步较晚,模具标准件生产、销售、推广和应用工作也比较落后,因此,模具标准件品种规格少、供应不及时、配套性差等问题长期存在,从而使模具标准件使用覆盖率一直较低。3、CAD/CAE/CAM 技术刚起步:CAD/CAE/CAM 是面向制造的工程设计技术群中的核心技术,是提高企业产品自主开发能力和产品档次的重要手段,也是提高企业对市场的应变能力和快速响应能力的重要途径,是现阶段应大力推广应用的关键共性技术,是模具设计的发展方向。4、缺乏相关人才:当今世界正进行着新一轮的产业调整,一些模具制造逐渐向发展中国家转移,中国正成为世界模具大国,但我国模具行业人才紧缺成为一个迫在眉睫的问题。模具行业是一个需长期积累经验的行业,现在的年轻人能坚持下来而有所成就的很少。由于最初的学习非常枯燥,因此许多初学者常半途而废。此外,我国传统教育方式对模具人才的培养存在不足。一些高校尽管在近几年内设立了模具专业,但由于受软硬件设施限制,培养出的学员实际技能不够。而社会上各种各样的模具培训班,由于缺乏规范的职业标准,因此学员质量良莠不齐。5、受到外资的挑战:目前世界制造业生产基地加速向中国转移,中国制造业又正迈向更高的发展阶段,对优质精密模具的需求不断上升。国际模具工业巨头继20世纪90 年代中期进入中国后,再掀投资热潮,目的正为抢占先机,中国本土模具工业面临国外先进技术与高质量制品的挑战,生存空间受挤压。6、缺乏自有品牌:企业开发能力弱、没有品牌,导致了经济效益欠佳,在市场中常处于被动地位。8六、参考文献1马忠臣等.现代模具工业发展述评J.模具技术,2006,032蒋桂芝.模具技术在国民经济中的地位J.机电产品开发与创新,2009,053洪慎章.现代模具技术的现状及发展趋势J.航空制造技术,2006,064吴存雷.浅谈模具产业的发展J.塑料工业,2006,105曹延安.中国模具工业现状J.现代零部件,2009,036陈德忠.我国模具先进制造技术的发展J.发展前沿,2000,097周永泰.中国模具工业的现状与发展J.行业展望,2007,128屈伟平.我国模具制造业发展现状、存在的问题及对策J.模具技术,2006,059周永泰.中国模具正在加速融入世界并实现国际共赢J.模具工业,2006,0410晓霏等.中国模具工业发展现状与展望J.航空制造技术,2008,0811 A. Y. C. Nee and M. W. Fu, “Determination of optimal parting directions in plastic injection mold design”, Annals CIRP, 46(1),pp. 429432, 1997.指导教师评语 签字: 年 月 日9 毕业论文(设计)开题报告题 目: 拉钩的冷冲模设计 系 别: 专 业:机械设计制造及其自动化班 级: 学 号: 学生姓名: 一、课题意义1、模具工业的分类我国模具设计与制造技术的发展经历了手工作坊制造阶段、工业化生产阶段和现代化生产阶段。伴随着计算机技术的快速发展, 数字化、信息化CADCAE/CAM技术和数控加工机床已普遍采用, 模具产业正处于高速发展阶段。模具是制造业的重要基础工艺装备。模具总体上可分为两大类: 金属材料制件成形模具,如冲压模具、锻造模具、压铸模具、挤压模具、拉丝模具、粉末冶金模具等; 非金属材料制件成形模具, 如塑料注射模具、压铸模具、挤出模具, 橡胶制件、玻璃制件和陶瓷制件成形模具等。模具的具体分类方法很多, 如按模具结构形式分, 冲压模具可分为简单模、连续模和复合模, 注塑模具可分为单分型面和双分型面注塑模具等; 按工艺性质分, 冲压模具可分为冲孔模、落料模、拉深模、弯曲模,塑模具可分为压塑模、传递模、注射模等。其中冲压模具、塑料模具、铸造模具、锻压模具、橡胶模具、粉末冶金模具、拉丝模具、无机材料成形模具等是最主要的八大类, 用于制造业中的几乎所有产品的生产。72、模具工业的地位随着社会的发展和科技的进步, 模具行业越来越被重视,模具技术在国民经济各个部门都得到广泛的应用,它不仅与整个机械行业密切相关,而且与人们的生活密切相关。模具工业是国民经济的基础产业,模具工业的发展水平标志着一个国家的工业水平及产品开发的能力。模具是生产各种工业产品的重要基础工艺装备,国民经济的五大支柱产业机械、电子、汽车、石化、建筑等都要求模具工业的发展与之相适应。模具因其生产效率高、产品质量好、材料消耗低、操作简单、生产过程易于实现机械化与自动化、生产成本低而获得广泛应用,利用模具可以加工出薄壁、重量轻、刚性好、形状复杂的零件;产品质量有模具保证,具有一模一样的的特点;这是其它加工制造业所无法完成的;模具是现代工业,特别是汽车、摩托车、航空、仪表、仪器、医疗器械、电子通信、兵器、家用电器、五金工具、日用品等工业必不可少的工艺装备。据资料统计,利用模具制造的零件数量,在飞机、汽车、摩托车、拖拉机、电机、电器、仪器仪表等机电产品中占80%以上;在电脑、电视机、摄像机、照相机、录像机等电子产品中占85%以上;在电冰箱、洗衣机、空调、电风扇、自行车、手表等轻工业产品中占90%以上;在子弹、枪支等兵器产品中占95%以上;在日用金属产品中占95%以上。可见,研究和发展模具技术,对于促进国民经济的发展具有特别重要的意义。目前,模具技术已成为衡量一个国家产品制造水平的重要标志之一。23、我国模具工业的现状近年来,我国模具工业的迅速发展是大家有目共睹的,中国模具工业的现状大致可以从以下3个方面来讲:(1)模具的产值与出口量增长明显。从整体情况来看,我国已经步入模具工业大国之列,但是距模具强国还有相当差距。(2)模具制造水平不断提高。近几年,以大型、精密、复杂、长寿命模具为代表的、技术含量较高的中高档模具的比重进一步提高,现在中高档模具所占比重已经达到35% 以上。模具的设计和制造水平也有了很大的发展,很多先进的模具设计与制造技术在我国的模具企业中得到应用,如CAD/CAE/CAM 等计算机辅助技术、高速加工技术、热流道技术、气辅技术、逆向工程等新技术得到广泛应用,E R P、P D M 等信息化管理技术正得到积极推广,这些先进技术的应用和信息化管理的实施极大地提高了模具企业的生产效率,缩短了生产周期。(3)我国模具行业已经形成了自己的骨干队伍。目前,我国约有模具生产厂点3 万余家,从业人员100余万人,在各个模具行业的骨干企业队伍中也涌现出了本行业的龙头企业。他们的生产装备先进,生产达到了一定规模,技术水平较高,而且产品具有自己的特点。10目前,中国约有模具生产厂2万余家,从业人员50多万人,全年模具产值达450亿元人民币以上。近年来,模具行业结构调整步伐加快,主要表现为大型、精密、复杂、长寿命模具和模具标准件发展速度高于行业的总体发展速度;塑料模和压铸模比例增大;面向市场的专业模具厂家数量及能力增加较快。随着经济体制改革的不断深入,“三资”及民营企业的发展很快。中国模具工业的发展在地域分布上存在不平衡性,东南沿海地区发展快于中西部地区,南方的发展快于北方。模具生产最集中的地区在珠江三角和长江三角地区,其模具产值约占全国产值的2/3以上。5二、现代模具的发展前景为了制造高精度、长寿命、高效的复杂腔结构的现代模具,需解决以下个方面的问题:1、模具材料及其表面处理技术。模具工业要上水平,材料应用是关键。因选材和用材不当,致使模具过早失效,大约占失效模具的45%以上。在模具材料方面常用的冷作模具钢有CrWMn、Cr12、Cr12MoV 和W6Mo5Cr4V2,新型冷作模具钢有65Nb、O12Al、CG-2、LD、GD、GM等;常用新型热作模具钢有美国H 1 3、瑞典QRO 80M、QRO 90SUPREME 等;常用塑料模具用钢有预硬钢(P20、SM1 B30)、时效硬化型钢(P21、PMS、SM2、日本NAK55等)、热处理硬化型钢(MnCrWV、日本S-STAR、瑞典胜百S-136 等)、粉末模具钢(日本DEX40 等);多工位精度冲模硬质合金(YG20、YG25 等)以及钢结构硬质合金( T L M W 5 0 、GW50 等)。在模具表面处理方面,主要趋势是:由渗入单一元素向多元素共渗、复合渗(如TD 法)发展;由一般扩散向CVD 、P V D、P C V D、离入渗入、离子注入等方向发展;可采用的镀膜有:TiC、TiN、TiCN、TiAN、CrN、Cr7C3、W2C 等,同时热处理手段由大气热处理向真空热处理发展。另外,激光强化、辉光离子氮化技术也日益受到重视。2、提高设计制造技术水平。当代模具的设计与制造已广泛采用计算机辅助设计与制造( C A D /CAM),设计过程程序化和自动化,使用程序模拟成形过程,采用交互式设计方法,发挥人和计算机的各自特长。数据库和计算机网络技术使设计人员拥有大量资料和信息。设计与制造之间的直接信息传输便于设计的反复修改。3、专业化生产及标准化。专业化生产是现代化工业生产的重要特征之一,工业先进国家模具专业化生产已达到75% 以上。标准化是实现模具专业化生产的基本前提,也是系统提高整个模具行业技术水平和经济效益的重要手段,这是机械制造业向深层次发展的必由之路。国外企业都极为重视模具的标准化,我国的模具标准化程度不足30%,而且标准品种少、质量低、交货期长,严重阻碍了模具的合理流向和效能的发挥,需尽快制订标准化规范Windows 用户界面。3目前, 国内模具市场不断扩大, 国际上将模具制造逐渐向我国转移的趋势和跨国集团到我国进行模具国际采购的趋向十分明显。因此,展望未来, 国际、国内模具市场总体发展前景美好。我国模具工业将会有一个继续高速发展的机遇期。只要我们把握这个机遇期, 中国模具工业不但会在量和质的方面继续有一个很大的提高, 而且一定会在行业结构、产品水平、开发创新能力、企业的体制与机制的方方面面取得较大进展。模具技术集合了机械、电子、化学、光学、材料、计算机、精密检测和信息网络等诸多学科, 是一个综合性多学科的系统工程。模具技术的发展趋势主要是模具产品向着更大型、更精密、更复杂及更经济快速的方向发展, 模具产品的技术含量不断提高, 模具制造周期不断缩短, 模具生产朝着信息化、无图化、精细化、自动化的方向发展, 模具企业向着技术集成化、设备精良化、产品品牌化、管理信息化、经营国际化的方向发展。7三、课题研究方法与计划课题的主要内容是冲压模具的设计,所以我首先应该深入学习机械设计、机械CAD/CAM、冷冲压技术等相关知识。冲压模具是模具类别中应用最广泛的一种,通过模具对金属的直接加压使其产生塑性变形,从而金属材料分离,以此来获得一定尺寸和性能的金属零件。模具的设计过程是和实际生产分不开的。我们应该充分研究设计任务书,了解产品用途,并进行冲压件的工艺性及尺寸公差等级分析,对于一些冲压件结构不合理或工艺性不好的,必须征询指导教师的意见后进行改进。在初步明确设计要求的基础上,可按以下步骤进行冲压总体方案的论证。1、主要任务与目标图1为某电器元件拉钩。该零件的制造方法为冷冲压成型,本课题要求分析封盖冲压件的成形工艺,设计模具,画出模具装配图及所有零部件的工程图,写出毕业论文。图1 挂钩2、主要内容与基本要求(1)分析垫片的冲压成形工艺。(2)模具设计。此零件厚度小,形状简单,要求设计的模具具有高精度和高成型效率。(3)打印图纸,写出毕业论文。(4)要求学生熟悉冷冲模具设计工艺,具有较强的机械设计能力。设计图纸的正确与否是评定本次设计水平的关键。四、参考文献1刘国胜.黄石理工学院学报. Journal of Huangshi Institute of Technology,2007,012蒋桂芝.模具技术在国民经济中的地位J.机电产品开发与创新,2009,053洪慎章.现代模具技术的现状及发展趋势J.航空制造技术,2006,064袁崇磷.模具标准件的发展趋势及需要解决的问题J.模具制造,2006,065曹延安.中国模具工业现状J.现代零部件,2009,036洪慎章.现代模具技术的现状及发展趋势J.航空制造技术, 2006,06 7周永泰.中国模具工业的现状与发展J.行业展望,2007,128机械工程师J.Mechanical Engineer, 2006,119林承全.论冲压模具设计制造与模具寿命的关系J.模具制造,2008,0610 1. K. S. Lee, J. Y. H, Fuh, Y. F. Zhang, A. Y. C. Nee and Z. Li,“IMOLD: an intelligent plastic injection mold design and assembly system”, Proceedings of the 4th International Conference On Die and Mould Technology, pp. 3037, Malaysia, 46 June 1997.11 A. Y. C. Nee and M. W. Fu, “Determination of optimal parting directions in plastic injection mold design”, Annals CIRP, 46(1),pp. 429432, 1997.指导教师审核意见: 签字: 年 月 日专业意见: 签字: 年 月 日院(系)意见: 签字: 年 月 日9 外文文献翻译译文题目: 拉钩的冷冲模设计 系 别: 专 业: 机械设计制造及其自动化班 级: 学 号: 学生姓名: 一、 外文原文A Parametric-Controlled Cavity Layout Design System for a Plastic Injection MouldM. L. H. Low and K. S. LeeDepartment of Mechanical Engineering, National University of Singapore, SingaporeToday, the time-to-market for plastic products is becoming shorter, thus the lead time available for making the injection mould is decreasing. There is potential for timesaving in the mould design stage because a design process that is repeatable for every mould design can be standardised. This paper presents a methodology for designing the cavity layout for plastic injection moulds by controlling the geometrical parameters using a standardisation template. The standardization template for the cavity layout design consists of the configurations for the possible layouts. Each configuration of the layout design has its own layout design table of all the geometrical parameters. This standardisation template is pre-defined at the layout design level of the mould assembly design. This ensures that the required configuration can be loaded into the mould assembly design very quickly, without the need to redesign the layout. This makes it useful in technical discussions between the product designers and mould designers prior to the manufacture of the mould. Changes can be made to the 3D cavity layout design immediately during the discussions, thus saving time and avoiding miscommunication. This standardisation template for the cavity layout design can be customised easily for each mould making company to their own standards.Keywords: Cavity layout design; Geometrical parameters;Mould assembly; Plastic injection mould design; Standardisationtemplate1. IntroductionPlastic injection moulding is a common method for the mass production of plastic parts with good tolerances. There are two main items that are required for plastic injection moulding. They are the injection-moulding machine and the injection mould. The injection-moulding machine has the mould mountedon it and provides the mechanism for molten plastic transfer from the machine to the mould, clamping the mould by the application of pressure and the ejection of the formed plastic part. The injection mould is a tool for transforming the molten plastic into the final shape and dimensional details of the plastic part. Today, as the time-to-market for plastic parts is becoming shorter, it is essential to produce the injection mould in a shorter time.Much work had been done on applying computer technologies to injection mould design and the related field. Knowledge-based systems (KBS) such as IMOLD 1,2, IKMOULD3, ESMOLD 4, the KBS of the National Cheng Kang University, Taiwan 5, the KBS of Drexel University 6, etc. were developed for injection mould design. Systems such as HyperQ/Plastic 7, CIMP 8, FIT 9, etc. are developed for the selection of plastic materials using a knowledge-based approach. Techniques have also been developed for parting design in injection moulding 1012.It has been observed that although mould-making industries are using 3D CAD software for mould design, much time is wasted in going through the same design processes for every project. There is great potential for timesaving at the mould design stage if the repeatable design processes can be standardized to avoid routine tasks. A well-organised hierarchical design tree in the mould assembly is also an important factor 13,14.However, little work has been done in controlling the parameters in the cavity layout design; thus this area will be our main focus. Although there are many ways of designing the cavity layout 15,16, mould designers tend to use only conventional designs, thus there is a need to apply standardisation at the cavity layout design level.This paper presents a methodology for designing the cavity layout for plastic injection moulds by controlling the parameters based on a standardisation template. First, a well-organised mould assembly hierarchy design tree had to be established. Then, the classification of the cavity layout configuration had to be made to differentiate between those with standard configurations and those with non-standard configurations. The standard configurations will be listed in a configuration database and each configuration has its own layout design table that controls its own geometrical parameters. This standardization template is pre-defined at the layout design level of the mould assembly design.2. Cavity Layout Design for a Plastic Injection MouldAn injection mould is a tool for transforming molten plastic into the final shape and dimensional details of a plastic part. Thus, a mould contains an inverse impression of the final part. Most of the moulds are built up of two halves: the front insert and the back insert. In certain mould-making industries, the front insert is also known as the cavity and the back insert is known as the core. Figure 1 shows a front insert (cavity) and a back insert (core). Molten plastic is injected into the impression to fill it. Solidification of the molten plastic then forms the part. Figure 2 shows a simple two-plate mould assembly.2.1 Difference Between a Single-Cavity and a Multi-Cavity MouldVery often, the impression in which molten plastic is being filled is also called the cavity. The arrangement of the cavities is called the cavity layout. When a mould contains more than one cavity, it is referred to as a multi-cavity mould. Figures 3(a) and 3(b) shows a single-cavity mould and a multi-cavity mould.A single-cavity mould is normally designed for fairly large parts such as plotter covers and television housings. For smaller parts such as hand phone covers and gears, it is always more economical to design a multi-cavity mould so that more parts can be produced per moulding cycle. Customers usually determine the number of cavities, as they have to balance the investment in the tooling against the part cost.2.2 Multi-Cavity LayoutA multi-cavity mould that produces different products at the same time is known as a family mould. However, it is not usual to design a mould with different cavities, as the cavities may not all be filled at the same time with molten plastic of the same temperature.On the other hand, a multi-cavity mould that produces the same product throughout the moulding cycle can have a balanced layout or an unbalanced layout. A balanced layout is one in which the cavities are all uniformly filled at the same time under the same melt conditions 15,16. Short moulding can occur if an unbalanced layout is being used, but this can be overcome by modifying the length and cross-section of the runners (passageways for the molten plastic flow from the sprue to the cavity). Since this is not an efficient method, it is avoided where possible. Figure 4 shows a short moulding situation due to an unbalanced layout.A balanced layout can be further classified into two categories: linear and circular. A balanced linear layout can accommodate 2, 4, 8, 16, 32 etc. cavities, i.e. it follows a 2n series. A balanced circular layout can have 3, 4, 5, 6 or more cavities, but there is a limit to the number of cavities that can be accommodated in a balanced circular layout because of space constraints. Figure 5 shows the multi-cavity layouts that have been discussed.3. The Design ApproachThis section presents an overview of the design approach for the development of a parametric-controlled cavity layout design system for plastic injection moulds. An effective working method of mould design involves organising the various subassemblies and components into the most appropriate hierarchy design tree. Figure 6 shows the mould assembly hierarchy design tree for the first level subassembly and components. Other subassemblies and components are assembled from the second level onwards to the nth level of the mould assembly hierarchy design tree. For this system, the focus will be made only on the “cavity layout design”.3.1 Standardisation ProcedureIn order to save time in the mould design process, it is necessary to identify the features of the design that are commonly used. The design processes that are repeatable for every mould design can then be standardised. It can be seen from Fig. 7 that there are two sections that interplay in the standardization procedure for the “cavity layout design”: component assembly standardisation and cavity layout configuration standardisation.3.1.1 Component Assembly StandardisationBefore the cavity layout configuration can be standardised, there is a need to recognise the components and subassemblies that are repeated throughout the various cavities in the cavity layout. Figure 8 shows a detailed “cavity layout design” hierarchy design tree. The main insert subassembly (cavity) in thesecond level of the hierarchy design tree has a number of subassemblies and components that are assembled directly to it from the third level onwards of the hierarchy design tree. They can be viewed as primary components and secondary components. Primary components are present in every mould design. The secondary components are dependent on the plastic part that is to be produced, so they may or may not be presentin the mould designs.As a result, putting these components and subassemblies directly under the main insert subassembly, ensures that every repeatable main insert (cavity) will inherit the same subassemblies and components from the third level onwards of the hierarchy design tree. Thus, there is no need to redesign similar subassemblies and components for every cavity in the cavity layout.3.1.2 Cavity Layout Configuration StandardisationIt is necessary to study and classify the cavity layout configurations into those that are standard and those that are nonstandard. Figure 9 shows the standardisation procedure of the cavity layout configuration.A cavity layout design, can be undertaken either as a multicavity layout or a single-cavity layout, but the customers always determine this decision. A single-cavity layout is always considered as having a standard configuration. A multi-cavity mould can produce different products at the same time or the same products at the same time. A mould that produces different products at the same time is known as a family mould, which is a non-conventional design. Thus, a multicavity family mould has a non-standard configuration.A multi-cavity mould that produces the same product can contain either a balanced layout design or an unbalanced layout design. An unbalanced layout design is seldom used and, as a result, it is considered to possess a non-standard configuration. However, a balanced layout design can also encompass either a linear layout design or a circular layout design. This depends on the number of cavities that are required by the customers. It must be noted, however, that a layout design that has any other non-standard number of cavities is also classified as having a non-standard configuration.After classifying those layout designs that are standard, their detailed information can then be listed into a standardization template. This standardisation template is pre-defined in the cavity layout design level of the mould assembly design and supports all the standard configurations. This ensures that the required configuration can be loaded very quickly into the mould assembly design without the need to redesign the layout.3.2 Standardisation TemplateIt can be seen from Fig. 10 that there are two parts in the standardisation template: a configuration database and a layoutde sign table. The configuration database consists of all the standard layout configurations, and each layout configuration has its own layout design table that carries the geometrical parameters. As mould-making industries have their own standards, the configuration database can be customised to take into account those designs that are previously considered as non-standard.3.2.1 Configuration DatabaseA database can be used to contain the list of all the different standard configurations. The total number of configurations in this database corresponds to the number of layout configurations available in the cavity layout design level of the mould design assembly. The information listed in the database is the configuration number, type, and the number of cavities. Table 1 shows an example of a configuration database. The configuration number is the name of each of the available layout configurations with the corresponding type and number of cavities. When a particular type of layout and number of cavities is called for, the appropriate layout configuration will be loaded into the cavity layout design.3.2.2 Layout Design TableEach standard configuration listed in the configuration database has its own layout design table. The layout design table contains the geometrical parameters of the layout configuration and is independent for every configuration. A more complex layout configuration will have more geometrical parameters to control the cavity layout.Figures 11(a) and 11(b) show the back mould plate (core plate) with a big pocket and four small pockets for assembling the same four-cavity layout. It is always more economical and easier to machine a large pocket than to machine individual smaller pockets in a block of steel. The advantages of machining a large pocket are:1. More space between the cavities can be saved, thus a smaller block of steel can be used.2. Machining time is faster for creating one large pocket compared to machining multiple small pockets.3. Higher accuracy can be achieved for a large pocket than for multiple smaller pockets.As a result, the default values of the geometrical parameters in the layout design table results in there being no gap between the cavities. However, to make the system more flexible, the default values of the geometrical parameters can be modified to suit each mould design where necessary.3.3 Geometrical ParametersThere are three variables that establish the geometrical parameters:1. Distances between the cavities (flexible). The distances between the cavities are listed in the layout design table and they can be controlled or modified by the user. The default values of the distances are such that there are no gaps between the cavities.2. Angle of orientation of the individual cavity (flexible). The angle of orientation of the individual cavity is also listed in the layout design table which the user can change. For a multi-cavity layout, all the cavities have to be at the same angle of orientation as indicated in the layout design table. If the angle of orientation is modified, all the cavities will be rotated by the same angle of orientation without affecting the layout configuration.3. Assembly mating relationship between each cavities (fixed). The orientation of the cavities with respect to each other is pre-defined for each individual layout configuration and is controlled by the assembly mating relationship between cavities. This is fixed for every layout configuration unless it is customised.Figure 12 shows an example of a single-cavity layout configuration and its geometrical parameters. The origin of the main insert/cavity is at the centre. The default values of X1 and Y1 are zero so that the cavity is at the centre of the layout (both origins overlap each other). The user can change the values of X1 and Y1, so that the cavity can be offset appropriately.Figure 13 shows an example of an eight-cavity layout configuration and its geometrical parameters. The values of X and Y are the dimensions of the main insert/cavity. By default, the values of X1 and X2 are equal to X, the value of Y1 is equal to Y, and thus there is no gap between the cavities. The values of X1, X2, and Y1 can be increased to take into account the gaps between the cavities in the design. These values are listed in the layout design table. If one of the cavities has to be oriented by 90, the rest of the cavities will be rotated by the same angle, but the layout design remains the same. The user is able to rotate the cavities by changing the parameter in the layout design table. The resultant layout is shown in Fig. 14.A complex cavity layout configuration, which has more geometrical parameters, must make use of equation to relate the parameters.4. System ImplementationA prototype of the parametric-controlled cavity layout design system for a plastic injection mould has been implemented using a Pentium III PC-compatible as the hardware. This prototype system uses a commercial CAD system (SolidWorks 2001) and a commercial database system (Microsoft Excel) as the software. The prototype system is developed using the Microsoft Visual C+ V6.0 programming language and the SolidWorks API (Application Programming Interface) in a Windows NT environment. SolidWorks is chosen primarily for two reasons:1. The increasing trend in the CAD/CAM industry is to move towards the use of Windows-based PCs instead of UNIX workstations mainly because of the cost involved in purchasing the hardware.2. The 3D CAD software is fully Windows-compatible, thus it is capable of integrating information from Microsoft Excel files into the CAD files (part, assembly, and drawing) smoothly 17.This prototype system has a configuration database of eight standard layout configurations that are listed in an Excel file. This is shown in Fig. 15(a). Corresponding to this configuration database, the layout design level, which is an assembly file in SolidWorks (layout.sldasm), has the same set of layout configurations. The configuration name in the Excel file corresponds to the name of the configurations in the layout assembly file, which is shown in Fig. 15(b).Every cavity layout assembly file (layout.sldasm) for each project will be pre-loaded with these layout configurations. When a required layout configuration is requested via the user interface, the layout configuration will be loaded. The user interface shown in Fig. 16 is prior to the loading of the requested layout configuration. Upon loading the requested layout configuration, the current layout configuration information will be listed in the list box.The user is then able to change the current layout configuration to any other available layout configurations that are found in the configuration database. This is illustrated in Fig. 17.The layout design table for the current layout configuration that contains the geometrical parameters can be activated when the user triggers the push button at the bottom of the user interface. When the values of the geometrical parameters are changed, the cavity layout design will be updated accordingly. Figure 18 shows the activation of the layout design table of the current layout configuration.5. A Case StudyA CAD model of a hand phone cover, shown in Fig. 19, is used in the following case study.Prior to the cavity layout design stage, the original CAD model has to be scaled according to the shrinkage value of the moulding resin to be used. The main insert is then created to encapsulate the shrunk part. This entire subassembly is known as the main insert subassembly (xxx cavity. sldasm), where “xxx” is the project name. Figure 20 shows the main insert subassembly. After the main insert subassembly is created, the cavity layout design system can be used to prepare the cavity layout of the mould assembly.5.1 Scenario 1: Initial Cavity Layout DesignIn a mould design, the number of cavities to be built in a mould is always suggested by the customers, as they have to balance the investment in the tooling against the part cost. Initially, the customers had requested a two-cavity mould to be designed for this hand phone cover. After t
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