本科毕业论文-中小企业信贷筹资困境及对策研究.docx

湖南交通工程学院毕业论文（设计） 题 目 塑件造型及注射模具 作者姓名 学 号 专 业 冲压工艺与模具设计 指导教师 2 0 1 5年 5 月目录摘要1. 塑件的工艺分析.()1.1塑件的材料分析.()1.2塑件的形状尺寸精度分析.()2. 模具结构形式 2.1分型面的确定.() 2.2型腔数目的确定分布.() 2.3浇注系统的设计.()3. 注塑机的选择.()4. 成型零件的设计 4.1结构设计.() 4.2工作尺寸计算.() 4.2.1影响塑件尺寸精度的主要因素.() 4.2.2型腔和型芯工作尺寸计算.() 4.2.3计算螺纹型芯的工作尺寸.() 4.3.4成型零件的强度、刚度计算.()5.脱模推出机构的设计 5.1推出机构的组成.() 5.2设计原则.() 5.3脱模力的计算.() 5.4复位零件和排气系统.() 6.导柱导向结构的设计 6.1导柱导向机构的作用.() 6.2导柱导套的选择.()7.温度系统的设计 7.1注射系统的结构设计.() 7.2冷却系统的结构设计.() 8.模架的确定和标准件的选用 8.1模架的选择（定模型腔板、型芯固定板、垫板尺寸）.() 8.2校核注射机（拉杆间距、开模行程）.() 8.3选用标准件（螺钉、推杆等）.() 9.模具工程图的绘制9.1绘制模具装配图.()9.2绘制模具零件图.()结论.()致谢.()参考文献.()摘要本次课程设计课题来源于生产实际，应用广泛，但成型难度相对较难，模具结构相对复杂，对我们初学模具设计的学生是一个很好的考验。它能加强对塑料模具成型原理的理解，同时锻炼对塑料成型模具的设计和制造能力。本次设计以注塑模具为主线，综合了成型工艺分析，模具结构分析，最后是模具的设计计算等一系列模具设计的所有过程。能很好的达到学以致用的效果。在设计该模具的同时结了以往模具设计的一般方法、步骤，模具设计中常用的公式、数据、模具结构及零部件。把以前学过的基础课程融汇到综合应用本次设计当中来，所谓学以致用。在设计中除使用传统方法外，同时使用了 autocad、proe等软件。 对于模具设计这个实践性非常强的设计课题，进行了大量的复习。对此我对于模具特别是塑料模具的设计步骤有了一个全新的认识，丰富了各种模具的结构和动作过程方面的知识，而对于模具的制造工艺更是实现了零的突破。在指导老师的协助下，同时在课后查阅过一些相关资料并看过一些案例了解了一些知识补充自己的不足，明确了模具的一般工作原理、制造、加工工艺。设计中，将充分利用和查阅各种资料，并与同学进行充分讨论，尽最的大努力搞好本次毕业设计。 在设计的过程中，有一定的困难，但有指导老师的悉心指导和自己的努力，相信会完满的完成毕业设计任务。由于学生水平有限，而且缺乏经验，设计中不妥之处在所难免，肯请老师指正。关键词：abs、注射模、双分型面一、 塑件的工艺分析1.1塑件的材料分析：基本特性 abs是由丙烯腈、丁二烯、苯乙烯共聚而成的。这三种组分的各自特性，使abs具有良好的综合力学性能。丙烯腈是abs有良好的耐化学腐蚀性及表面硬度，丁二烯使abs坚韧，苯乙烯使它有良好的加工性和染色性能。abs无毒、无味、呈微黄色，成型的塑料件有较好的光泽。密度为1.021.05g/cm3。abs有极好的抗冲击强度，且在低温下也不迅速下降。有良好的力学强度和一定的耐磨性、耐寒性、耐油性、耐水性、化学稳定性和电气性能。水、无机盐、碱、酸类对abs几乎无影响，在酮、醛、酯、氯代烃中会溶解或形成乳浊液，不溶于大部分醇类及烃类溶剂，但与烃长期接触会软化溶胀。abs塑料表面受冰醋酸、植物油等化学药品的侵蚀会引起应力开裂。abs有一定的硬度和尺寸稳定性，易于成型加工。经过调色可配成任何颜色。其缺点是耐热性不高，连续工作温度为70c左右，热变形温度约为93c左右。耐气候性差，在紫外线作用下易变硬脆弱。根据abs中三种组分之间的比例不同，其性能也略有差异，从而适应各种不同的应用。根据应用不同可分为超高冲击型。高冲击型、中冲击型、低冲击型和耐热型等。主要用途 abs在机械工业上用来制造齿轮、泵叶轮、轴承、把手、管道、电机外壳、仪表壳、仪表盘、水箱外壳、蓄电池槽、冷藏库和冰箱衬里等、汽车工业上用abs制造汽车挡泥板、扶手、热空气调节导管、加热器等，还有用abs夹层板制小轿车车身。abs还可用来制作水壳表、纺织器材、电器零件、文教体育用品、玩具、电子琴及收录机壳体、食品包装容器、农药喷雾器及家具等。 成型特点abs在升温时粘度增高，所以成型压力较高，塑料上的脱模斜度宜稍大；abs易吸水，成型加工前应进行干燥处理；易产生溶解痕，模具设计时应注意尽量减少浇注系统对料流的阻力；在正常的成型条件下，壁厚、熔料温度及收缩率影响极小。要求塑件精度高时，模具温度可控制在5060，要求塑件光泽和耐热时，应控制在6080塑料的成型工艺参数的确定查 屈华昌.塑料成型工艺与模具设计第二版，表3-1、各种塑料的注射工艺参数得：结构特点线性结构非结晶型使用温度小于70性能特点机械强度较好，有一定耐磨性成型特点成型效果好，成型前原料要干燥适用注射机类型螺杆柱塞式均可密度(g/cm)1.021.05注射压力(mpa)7090螺杆转速(r/min)3060计算收缩率(%)0.30.8模具温度()5070预热温度()8085时间/h35吸水率24h(%)0.3拉伸屈服强度(mpa)1800抗拉屈服强度(mpa)50喷嘴温度()180190保压力时间（s）1530冷却时间（s）1530料筒温度前段（）料筒温度中段（）料筒温度后段（）80200c165180c150170c注射时间（s）351.2塑件的形状尺寸精度分析： 该塑件整体结构简单，多数为曲面特征，除了配合尺寸精度要求较高外其他尺寸精度要求相对较低，但表面粗糙度要求较高，结合其材料性能，故选精度等级：mt7级。材料为abs，成型工艺好，可以注射成型。1.精度等级：影响塑件精度的因素有很多，塑料的收缩率的波动、注塑成型条件（时间、压力、温度）使用的磨损程度，塑件形状、模具结构（浇口、分型面的选择）成型工艺条件的变化，飞边、斜度、以及脱模斜度和成型制品的尺寸变化等等。在一般的生产设计过程中，为了降低模具的加工难度和模具的生产成本，在满足塑件使用要求的条件下，选取等级公差，便于加工。结合本章设计具体情况，查参考文献表3-8查的，该塑料件尺寸精度为mt7级，对应的模具精度为，2.脱模斜度：由于塑件冷却后产生收缩，会紧紧地包住模具型芯、型腔中凸出的部分，使塑件脱出困难，强行取出会导致塑件表面擦伤、拉毛。为了方便脱模，塑件设计时必须考虑与脱模（及轴心）方向平行的内、外表面，设计足够的脱模斜度，本塑件没有特殊狭窄细小的部位，可以不设计斜度。最小脱模斜与塑料性能、收缩率、塑件的几何形状等因素有关二模具结构形式2.1注射机型号的选择2.1.1模具所需塑料熔体注射量该产品材料为abs，查书本得知其密度为1.03-1.05，收缩率为0.5%，计算其平均密度为1.04.一副模具所需塑料体积： v=nv1+v2=1.15nv1=8.54式中单个塑件的体积（由计算得单个塑件体积为8.54） 浇注系统的体积（在学校设计时） n初步设定的型腔数量（取2） 质量m=pv=8.972.1.2 分型面上的投影面积及所需锁模力 塑件和流道凝料在分型面上的投影面积： 式中单个塑件在分型面上的投影面积； 流道凝料在分型面上的投影面积（分流道暂定为半圆形直径为8mm，长度为60mm)。 所需锁模力： 式中塑料熔体对型腔的平均压力（由查表得abs对型腔的压力为30mpa）2.1分型面的确定分型面对制品表面质量、尺寸精度、形位精度、脱模型腔型芯结构和排气系统以及进料浇口都有很大的影响。此外，分型面和模具的制造方便与否也有很大的关系。因此，一定要选择合适的分型面，选择分型面时一般要准循以下几个原则。1）分型面应选在塑件外形最大轮廓处当已经初步确定塑件的分型方向后分型面应选在塑件外形最大轮廓处，即通过该方向塑件的截面积最大，否则塑件无法从形腔中脱出。2）确定有利的留模方式，便于塑件顺利脱模从制件的顶出考虑分型面要尽可能地使制件留在动模边，当制件的壁相当厚但内孔较小时，则对型芯的包紧力很少常不能确切判断制件中留在型芯上还是在凹模内。这时可将型芯和凹模的主要部分都设在动模边，利用顶管脱模，当制件的孔内有管件（无螺纹连接）的金属嵌中时，则不会对型芯产生包紧力。3）保证制件的精度和外观要求与分型面垂直方向的高度尺寸，若精度要求较高，或同轴度要求较高的外形或内孔，为保证其精度，应尽可能设置在同一半模具腔内。因分型面不可避免地要在制件中留下溢料痕迹或接合缝的痕迹，故分型面最好不选在制品光亮平滑的外表面或带圆弧的转角处。在此处键入公式。滑的外表面或带圆弧的转角处。4）分型面应使模具分割成便于加工的部件，以减少机械加工的困难。5）不妨碍制品脱模和抽芯。在安排制件在型腔中的方位时，要尽量避免与开模运动相垂直方向的避侧凹或侧孔。6）有利于浇注系统的合理处置。7）尽可能与料流的末端重合，以利于排气。根据本该塑件的具体结构和以上确定分型面的基本原则，选择侧浇口单分型面。如图所示：2.2型腔数目的确定及分布2.1 型腔数目的确定 为了制模具与注塑机的生产能力相匹配，提高生产效率和经济性，并保证塑件精度，模具设计时应确定型腔数目。型腔数目的确定一般可以根据经济性、注射机的额定锁模力、注射机的最大注射量、制品的精度等。一般来说，大中型塑件和精度要求高的小型塑件优先采用一模一腔的结构，但对于精度要求不高的小型塑件（没有配合精度要求），形状简单，又是大批量生产时，若采用多型腔模具可提供独特的优越条件，使生产效率大为提高。根据塑件的结构及尺寸精度要求,该塑件在注射时采用一模二腔。2.2.2.型腔数目的分布如图所示：2.2浇注系统的设计浇注系统是指注射模中从主流道的始端到型腔之间的熔体进料通道，它的作用是将塑料熔体顺利的充满型腔的各个部位。正确设计浇注系统对获得优质的塑料制品极为重要。注射成型的基本要求是在合适的温度和压力下使足量的塑料熔体尽快充满型腔，影响顺利充模的关键之一就是浇注系统的设计。5.1主流道设计 主流道通常位于模具中心塑料熔体的入口处，形状一般为圆锥形，便于熔体的流动和开模时主流道凝料的顺利拔出。由于主流道和高温塑料熔体以及注射机喷嘴反复接触，故再设计时常设计为可拆卸更换的浇口套。5.1.1主流道的作用主流道（也叫进料口），它是连接注射机料筒喷嘴和注射模具的桥梁，也是熔融的塑料进入模具型腔时最先经过的地方。主流道的大小和塑料进入型腔的速度及充模时间长短有着密切关系。若主流道太大，其主流道塑料体积增大，回收冷料多，冷却时间增长，使包藏的空气增多，如果排气不良，易在塑料制品内造成气泡或组织松散等缺陷，影响塑料制品质量，同时也易造成进料时形成旋涡及冷却不足，主流道外脱模困难；若主流道太小，则塑料在流动过程中的冷却面积相应增加，热量损失增大，粘度提高，流动性降低，注射压力增大，易造成塑料制品成形困难。主流道部分在成型过程中，其小端入口与注射机喷嘴及一定温度、压力的塑料熔要冷热交替地反复接触，属易损件，对材料的要求较高因而模具的主流道部分常设计成可拆卸更换的主流道衬套式（俗称浇口套），以便有效地选用钢材单独进行加工和热处理。一般采用碳素工具钢t8a、t10a等，热处理要求淬火5357hrc。在一般情况下，主流道不直接开设在定模板上，而是制造成单独的浇口套，镶定在模板上。小型注射模具，批量生产不大，或者主流道方向与锁模方向垂直的模具，一般不用浇口套，而直接开设在定模板上。浇口套是注射机喷嘴在注射模具上的座垫，在注射时它承受很大的注射机喷嘴端部的压力同时由于浇口套末端通过流道浇口与型腔相连接，所以也承受模具型腔压力的反作用力。为了防止浇口套因喷嘴端部压力而被压入模具内，浇口套的结构上要增加台肩，并用螺钉紧固在模板上，这样亦可防止模腔压力的反作用力而把浇口套顶出。5.1.2主流道设计要点(1) 浇口套的内孔（主流道）呈圆锥形，锥度26。若锥度过大会造成压力减弱，流速减慢，塑料形成涡流，熔体前进时易混进空气，产生气孔；锥度过小，会使阻力增大，热量损耗大，表面黏度上升，造成注射困难。(2) 浇口套进口的直径d应比注射机喷嘴孔直径d大0.5mm。若等于或小于注射机喷嘴直径，在注射成型时会造成死角，并积存塑料，注射压力下降，塑料冷凝后，脱模困难。由注塑机的型号里面得知13 d = ，所以得 3.5 4.0 d= : mm。本设计取4.0mm。(3) 浇口套内孔出料口处（大端）应设计成圆角r，一般为0.53mm。(4) 浇口套与注射机喷在接触处球面的圆弧度必须吻合。设球面浇口套球面半径为sr，注射机球面半径为r，其关系式如下：srr0.51mm 浇口套球面半径比注射机喷嘴球面半径大，接触时圆弧度吻合的好.三、 注射机的选择四、 成型零件的设计1. 结构设计模具中决定塑件几何形状和尺寸的零件称为成型零件，包括凹模、型芯、镶块、成型杆和成型环等。成型零件工作时，直接与塑件接触，承受塑件熔体的高压、料流的冲刷、脱模时与塑件的摩擦。因此，成型零件要有正确的几何形状，较高的尺寸精度，较低的表面粗糙度值，还要求结构合理，较高的强度、刚度、较好的耐磨性。设计成型零件时，应根据塑件的特性和塑件的结构及使用要求，确定型腔的总体结构，选择分型面和浇口位置，确定脱模方式、排气部位等，根据成型零件的加工、热处理、装配等要求进行成型零件结构设计，计算成型零件工作尺寸，进行强度和刚度校核。2.工作尺寸计算1.型腔径向尺寸3.影响塑件尺寸的主要因素 1.塑件收缩率的影响 塑件成型后的收缩率与塑料的品种，塑件的形状、尺寸、壁厚，模具的结构，成型的工艺条件等因素有关。其尺寸变化值为： s=（smax-smin）ls 式中 s为塑件收缩率波动所引起的塑件尺寸误差 smax为塑件的最大收缩率 smin为塑件的最小收缩率 ls为塑件的基本尺寸 2.模具成型零件的制造误差 成型零件工作尺寸公差可取塑件公差的1/31/4或取it78级作为模具制造公差。 3.模具成型零件的磨损 对于中小型塑件，最大磨损量可取塑件公差的1/6，对于大型塑件可取1/6以下。4.模具安装配合的误差 综上所述，塑件在成型过程中产生的最大尺寸误差是上述误差的总和。即： =z+c+s+j+a 式中为塑件的成型误差 z为模具成型零件制造误差 c为模具成型零件在使用中最大磨损量 s为塑件收缩率波动所引起的塑件尺寸误差 j为模具成型零件因配合间隙变化而引起塑件尺寸的误差 a为因安装固定成型零件而引起的塑件尺寸误差您好，为你提供优秀的毕业论文参考资料，请您删除以下内容，o(_)o谢谢！a large group of tea merchants on camels and horses from northwest chinas shaanxi province pass through a stop on the ancient silk road, gansus zhangye city during their journey to kazakhstan, may 5, 2015. the caravan, consisting of more than 100 camels, three horse-drawn carriages and four support vehicles, started the trip from jingyang county in shaanxi on sept 19, 2014. it will pass through gansu province and xinjiang uygur autonomous region, and finally arrive in almaty, formerly known as alma-ata, the largest city in kazakhstan, and dungan in zhambyl province. the trip will cover about 15,000 kilometers and take the caravan more than one year to complete. the caravan is expected to return to jingyang in march 2016. then they will come back, carrying specialty products from kazakhstan a small art troupe founded six decades ago has grown into a household name in the inner mongolia autonomous region. in the 1950s, ulan muqir art troupe was created by nine young musicians, who toured remote villages on horses and performed traditional mongolian music and dances for nomadic families. the 54-year-old was born in tongliao, in eastern inner mongolia and joined the troupe in 1975.he says there are 74 branch troupes across inner mongolia and actors give around 100 shows every year to local nomadic people. i can still recall the days when i toured with the troupe in the early 80s. we sat on the back of pickup trucks for hours. the sky was blue, and we couldnt help but sing the folk songs, nasun says. the vastness of inner mongolia and the lack of entertainment options for people living there, made their lives lonely. the nomadic people were very excited about our visits, nasun recalls. we didnt have a formal stage. the audience just sat on the grass. usually, the performances became a big party with local people joining in. for him, the rewarding part about touring isnt just about sharing art with nomadic families but also about gaining inspiration for the music and dance. ulan muqir literally translates as red burgeon, and todays performers of the troupe still tour the regions villages and entertain nomadic families, but their fame has spread around the world. on may 16 and 17, nearly 100 singers and dancers from the troupe performed at beijings poly theater. their show, titled ulan muqir on the grassland, depicted the history and development of the art troupe. being from the region allowed me to embrace the culture of inner mongolia and being a member of the troupe showed me where i belonged, nasun, the art troupes president, who is also a renowned tenor, tells china daily. during a tour in 1985, he went to a village and met an elderly local man, who told him a story about his friendship with a solider from shenyang, capital of northeast chinas liaoning province, decades ago. the solider gave the old man a handmade saddle when they bid farewell. the story inspired nasun to write carved saddle, a song that later became one of his most popular numbers. now, every year, nasun recruits young singers and dancers for the troupe. the troupe has also designed a new repertoire, which is mostly based on the daily lives of mongolian people, especially the lives of nomadic families, and has combined contemporary musical elements with folk songs of the region. haimu, a 25-year-old khoomei (a local variant of overtone singing) singer, joined the troupe three years ago. along with a six-member band, he performs fast songs and soft ones that he writesall while playing the horse-head fiddle.although i learned the piano since childhood and grew up listening to various kinds of music, to me, the folk music of inner mongolia is the root, he says. performing in remote villages is pleasant. i feel at home on the boundless grasslands, and the warm people there make me feel fulfilled. the first round of spring auction season in beijing ended last week, but it failed to create much spring in the art market. although two pieces of chinese painting fetched more than 100 million yuan, the decline in trading volume and sale rate showed a downturn this year. in the “grand view: chinese painting highlight” session at china guardian 2015 spring auctions, pan tianshous representative work eagle, rock and flora hit a record auction price of 279 million yuan, while li kerans masterwork jinggang mountain fetched 126.5 million yuan, an unexpected high in recent years. however, the trading volume fells to 1.87 billion yuan from 2.22 billion yuan in the same period the year before. the huangchen 2015 spring auctions, which recorded 42.5 million yuan in total sales, experienced the same. the section number went down to 5 from 12 compared to last year. according to expert shao jianwu, the art market did not attract much excitement this year due to the booming stock market and the persistent problems of forgery and fake deals. the two pieces of chinese painting notched up high price this spring due to their own value not due to a revival in the market. the successful transaction of two works with a hammer price of more than 100 million yuan once again confirms that valuable and rare works of high quality always earn the long-lasting high price. chinese painting and calligraphy is still the pillar of the market. however, the overall sales rate has dropped slightly, which reflects the demand for the ordinary auction goods has weakened,” said the president of china guardians hu yanyan. besides, the entry of new buyers also makes certain changes to the direction of purchasing. in a word, the overall market trend is very unpredictable. although china guardian 2015 spring auctions has achieved remarkable results, it does not mean that the market has walked out of the predicament. we still have to wait for the big economic boom to invigorate the art market.” even so, the hot pursuit of some special items appeared this spring. a special session of china guardian spring auctions titled “fine giltbronze buddhist images” achieved a great deal with total sales volume of 41.89 million yuan and 92 percent sale rate. the 5th shamar rinpoche statue from 16-17th century of tibet was sold for 5.06 million yuan. the beijing chengxuan auctions featured almost 2,800 items of coins and stamps in three sessions with good sale rate. the huachen auctions also set a special session of photographs under the condition of large-scale decline of auction sessions. there was a palpable dull thud of disappointment that accompanied the return of the imperial entourage of zhen huan to her homeland. it followed a couple years of hushed excitement as chinese fans were fed tidbits about their proud concubine who was supposed to conquer the high ground of the north american market. zhen huan is, of course, the title character of the legend of zhen huan, a 2011 television series that swept china off its feet and later took other asian countries by storm. two years ago, it was reported that hbo, a premium cable service headquartered in the united states, was going to air it in north america after some modification. now, a condensed version that provides english subtitles but no dubbing has finally been made available on netflix for online streaming. this version, highly anticipated as a milestone in chinas cultural foray overseas, has been widely panned by its home audience. retitled empresses in the palace, the american version has been shortened from its original 76 episodes at 45 minutes each, to six 90-minute episodes. the quick pacing threw off many native viewers, who are accustomed to a more leisurely daytime-soap-style narrative rhythm. (chinese tv stations would run two or three episodes every day.) i did not finish the full-length version and found the truncated one not difficult to follow. whats lost, i believe, are the interesting setups and pauses that illuminate the chinese art of storytelling. much of the plot is still there. it is the flavor that was sacrificed. the american edition uses the framework of the empress dowager in her senior years reminiscing at the beginning and the end of each episode, hinting at whats to come and recapping the key points. this device, not used in the original, is culturally understandable but artistically mediocre. what puzzles me is the two new songs for the opening and end credits. they were written in english, but sung by chinese with an uncomfortable accent. they were obviously designed to appeal to an english-speaking base, but do not jibe with the chinese dialogue. speaking of the dialogue, the english translation, picked apart by some chinese, is too literal for my taste. i can imagine a typical american hit by a flurry of royal ranks, addresses and greetings, even multiple names and titles for the same person. the first half hour must be a swamp to wade through, very much like my experience of getting through a tolstoy tome with its endless inflections of names transliterated into lengthy chinese. i see the choice of verbatim translation as an effort for conveying exotica. it is fairly competent, with no error that i could detect, but fails to rise above words or capture the essence of the language. a cultural product usually crosses over to a foreign territory first by an emphasis on the commonalities. but whether inside or outside china, the temptation to sell it for the differences is just too great. sure, the sumptuous sets and costumes are a big attraction, but the narrative technique has becomehow shall i put