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毕业设计(论文)
题 目 塑料杯托注射模设计
常州大学本科生毕业设计(论文)(居中 宋体 小四号)
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本人所呈交的毕业论文(设计)是我在导师的指导下进行的研究工作及取得的研究成果。据我所知,除文中已经注明引用的内容外,本论文(设计)不包含其他个人已经发表或撰写过的研究成果。对本论文(设计)的研究做出重要贡献的个人和集体,均已在文中作了明确说明并表示谢意。
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注 意 事 项
1.设计(论文)的内容包括:
1)封面(按教务处制定的标准封面格式制作)
2)原创性声明
3)中文摘要(300字左右)、关键词
4)外文摘要、关键词
5)目次页(附件不统一编入)
6)论文主体部分:引言(或绪论)、正文、结论
7)参考文献
8)致谢
9)附录(对论文支持必要时)
2.论文字数要求:理工类设计(论文)正文字数不少于1万字(不包括图纸、程序清单等),文科类论文正文字数不少于1.2万字。
3.附件包括:任务书、开题报告、外文译文、译文原文(复印件)。
4.文字、图表要求:
1)文字通顺,语言流畅,书写字迹工整,打印字体及大小符合要求,无错别字,不准请他人代写
2)工程设计类题目的图纸,要求部分用尺规绘制,部分用计算机绘制,所有图纸应符合国家技术标准规范。图表整洁,布局合理,文字注释必须使用工程字书写,不准用徒手画
3)毕业论文须用A4单面打印,论文50页以上的双面打印
4)图表应绘制于无格子的页面上
5)软件工程类课题应有程序清单,并提供电子文档
5.装订顺序
1)设计(论文)
2)附件:按照任务书、开题报告、外文译文、译文原文(复印件)次序装订
3)其它
塑料杯托注射模设计
摘 要:本课题是塑料杯托注射模设计。首先进行塑件的工艺分析,通过对其外形、材料、收缩率等参数的分析来确定模具设计的方案。通过分析塑件的材料、大小选择注塑机,之后进行注塑机的校核。该塑件采用侧向分型抽芯的方式来成型,又是一模两腔,设计模具的结构时包括定位环、浇口套、模具的型腔结构、型芯的结构、斜导柱、楔形块、滑块、导滑槽、挡板、复位杆、拉料杆、导向机构、推出机构、浇注系统、排气系统、模温调节系统等。
该设计方案简单明了,提高塑件的生产精度和生产效率,节约成本,同时这样设计的目的是为了使设计规范化,生产时制造人员更加清楚,能够规范化生产。同时也可以将自己之前所学的理论知识与实现相结合,并让自己养成良好的设计习惯,又锻炼了自己的配合意识。
关键词:塑料杯托;注射模;侧向分型;
说明:①题名以简明的词语恰当、准确地反映论文最重要的特定内容(一般不超过25字),应中英文对照。题名通常由名词性短语构成,应尽量避免使用不常用缩略词、首字母缩写字、字符、代号和公式等。如题名内容层次很多,难以简化时,可采用题名和副题名相结合的方法,其中副题名起补充、阐明题名的作用。题名和副题名在整篇学位论文中的不同地方出现时,应保持一致。
②摘要应具有独立性和自含性,即不阅读论文的全文,就能获得必要的信息。摘要的内容应包含与论文等同量的主要信息,供读者确定有无必要阅读全文,也可供二次文献采用。摘要一般应说明研究工作目的、方法、结果和结论等,重点是结果和结论。
③中文摘要一般字数为300~600字,外文摘要实词在300个左右。如遇特殊需要字数可以略多。
Title(居中 Times New Roman字体 三号 粗体)
Abstract(Times New Roman 小四号 粗体):内容(Times New Roman 小四号)
Key words(Times New Roman 小四号 粗体):内容(Times New Roman 小四号)
术 语 表
说明:术语表是符号、标志、缩略词、首字母缩写、计量单位、术语等的注释说明。
目 录
摘要·········································································································································Ⅰ
术语表······································································································································Ⅲ
目录··········································································································································Ⅳ
引言······································································································································1
1 塑件的工艺分析·····················································································································1
1.1外形分析······························································································································1
1.2材料分析······················································································································1
1.3体积与质量······················································································································1
1.4塑料成型机械·····················································································································1
2 注塑机的选择························································································································3
3注塑机的校核······················································································································5
4模具结构的设计···················································································································10
4.1 型腔布局·····························································································································1
4.2分型面的设计······················································································································1
4.3浇注系统······························································································································3
4.3.1主流道设计························································································································5
4.3.2分流道设计······················································································································10
4.3.3浇口套设计························································································································1
4.3.4定位环······························································································································1
4.3.5浇口设计····························································································································3
4.3.6冷料井·······························································································································5
4.4成型零件的结构设计········································································································10
4.4.1定模型芯························································································································10
4.4.2动模型芯·························································································································10
4.4.3型腔设计··························································································································10
4.5侧向分型····························································································································10
4.5.1侧向分型的方式··············································································································10
4.5.2抽拔距的计算·················································································································10
4.5.3斜销计算·························································································································10
4.5.4导滑槽····························································································································10
4.5.5楔紧块····························································································································10
4.5.6滑块·······························································································································10
4.5.7滑块定位装置················································································································10
4.6模架的选择························································································································10
4.7推出机构···························································································································10
4.8导向机构····························································································································10
4.8.1动定模导向····················································································································10
4.8.2推板导向························································································································10
4.9排气系统···························································································································10
4.10冷却系统的设计········································································································10
5 结论······································································································································35
参考文献··································································································································38
致谢··········································································································································40
附录A······································································································································41
附录B······································································································································42
引 言
1. 课题研究的意义,国内外研究现状和发展趋势
1.1本课题研究的意义
在现代生产中,模具是大批量生产各种产品和日用生活品的重要工艺装备,它以其特定的形状通过一定的方式使原料成型。我国塑料模具工业起步晚,底子薄,与工业发达国家相比存在很大的差距。随着塑料工业的不断发展,对塑料模具提出越来越高的要求是正常的,因此,精密、大型、复杂、长寿命塑料模具的发展将高于总量发展速度,注射成型是当今市场上最常用、最具前景的塑料成型方法之一,因此注塑模具作为塑料模的一种,就具有很大的市场需求量。而传统模具设计制造技术,根本不能满足市场对模具的要求。因此,研制和开发新的模具设计、制造技术势在必行。由于模具成型具有优质、高产、省料和成本低等特点,现已在国民经济各个部门,特别是汽车、拖拉机、航天航空、仪器仪表、机械制造、家用电器、石油化工、轻工日用品等部门得到极其广泛的应用。塑料杯托在日常生活中比较常见。
因为每个家庭都有很多家用电器,当然杯托也是这些家用电器的必备产品。选择它的目的在于它时常出现在我们的生活中,另外我们遇到的问题也不是什么大的问题,如果我们掌握了它的结构,以及它的性能,还有它的原理,那么每当我们发现它的毛病时,就可以自己动手去操作,把它的问题找出来。一方面可以解决问题,另一方面也可以发现它的哪些地方会经常出现问题,在我们选择杯托时会留意一下。本课题为注塑模具设计,模具作为一种高附加值和技术密集型产品,其技术水平的高低已经是衡量一个国家制作业水平高低的重要标志之一,而本题的研究将涉及一些二维及三维软件软件的应用,如AutoCad等,以及相关软件的应用。通过本次课题对我们进行熟悉模具的设计,产品的开发等都有很大的意义。
1.2国内外的现状
在塑料制品的生产中,高质量的模具设计、现金的模具制造设备、合理的加工工艺、幼稚的模具材料和现代化成形设备等都是成形优质塑料件的重要条件。国外发达国家模具标准化程度为七成到八成,而我国只有三成左右。如能广泛应用模具标准件,将会缩短模具设计制造周期四分之一,并可减少由于使用者自制模具件而造成的工时浪费。应用模具计算机辅助绘图技术设计模具已较为普遍,推广使用模具标准件,能够实现部分资源共享,这会大大减少模具设计的工作量和工作时间,对于发展计算机辅助绘图技术、提高模具的精密度有重要意义。目前,我国制造业的水平仍然很低,在1995年人均制造业增加值仅203.5美元/人。也仅仅相当于1950年美国的水平(1530美元/人),略高于日本1965年的水平,因此,我国的制造技术与国际先进水平相比还存在着阶段性差距。
近年来我国模具发展的重点放在精密、大型、复杂、长寿命模具上,并取得了可喜成就。虽然我国模具工业与取得较大的发展,但仍然不能满足国内经济高速发展的需求。“十五”期间,我国模具市场在汽车、家用电器、电子及通信产品、建材、玩具、一起仪表等行业将会有更大的需求。现在,国内企业已认识到了模具标准化的重要性,目前有一定生产规模的模具标准件生产企业有一百余家,主要产品有塑料模架、侧冲装置、推杆推管等,其中塑料模架已可生产较大型产品,为发展大型精密模具打下了基础。但是我们的小型模具,比如像杯托这样的家用产品,因为它的产量较大,并且人们的生活中也不可缺。它在我们的生活中所占的比重很大,这是不容我们忽视的。
一些重要的模具标准必须重点发展,而且其发展速度应快于模具的发展速度,这样才能不断提高我国的模具标准化水平,从而提高模具质量,缩短模具生产周期及降低成本。由于我国的模具产品在国际市场上占有较大的价格优势,因此对于出口前景好的模具产品也应作为重点来发展。而且应该是目前已有一定基础,有条件、有可能发展起来的产品。
1.3发展趋势
(1) 模具CAD/CAM/CAE正向集成化、三维化、智能化、网络化方向发展;
(2) 模具监测、加工设备向精密、高效和多功能方向发展;
(3) 快速荆棘制模技术;
(4) 模具材料及表面处理技术发展迅速;
(5) 模具工业新工艺、新理念和新模式逐步得到了认同。
1、 塑件的工艺分析
1.1外形分析
该塑件为塑料杯托,是一种常见的生活用品。
1.2材料分析
该塑件成型时迅速,常温下一般不溶于有机溶剂,能耐醛、酯、醚、烃及弱酸、弱碱,耐汽油及润滑油性能也很好,有较高的抗拉,抗压性能和突出的耐疲劳强度,尺寸稳定、吸水率小,具有良好的耐摩性能,还有良好的电气绝缘性能。因此可选用聚甲醛(POM),具体参数如下:
材料
比重
成型收缩率
成型温度
特性
聚甲醛(POM)
1.41-1.43g/cm3
1.2-3.0%
170-200°C
吸水性小、冷却速度快、摩擦系数小、有弹性
1.3体积和质量
1.4塑件成性要求
该塑件尺寸精度要求不高,壁厚均匀,同时化学性能稳定,绝缘性好,不易产生损坏和断裂现象,易于成形。塑件表面平整,要求无飞边或缩孔现象。
2、注塑机的选择
由上面可知,塑件的体积为13cm3,一模两腔共26cm3,
V塑件=13cm3
2V塑件=26cm3
凝料体积约为塑件体积的20%
V凝料=2V塑件×20%=5.2cm3
V总=31.2cm3
一般一个注塑成型周期内所需注射的塑料熔体容量占注塑机额定量的50%-80%,所以注
塑机的额定量为
V额>31.2÷0.8=39cm3
根据上述要求选择SZ-60/40的注塑机,部分参数如下:
项目 型号
SZ-60/40
螺杆直径/mm
30
理论注塑量/cm3
60
注射压力/MPa
180
注射速率/(g/s)
70
锁模力/kN
400
模板行程/mm
250
定位孔直径/mm
80
定位孔深度/mm
10
喷嘴球半径/mm
10
3、 注塑机的校核
3.1锁模力的校核
注塑机的额定锁模力F锁=400MPa
POM的型腔压力p腔=35MPa
F锁>p腔×A/1000
式中:F锁——锁模力(kN)
p腔——型腔压力(MPa)
A ——塑件及流道系统在分型面上的投影面积(mm2)
A=4462mm2
p腔×A/1000=156.17kN
符合锁模力的要求。
3.2开模行程和塑件推出距离的校核
S>H+(5-10mm)
H——塑件的高度(mm)
S——注塑机最大开模行程(mm)
S=250mm
H=79mm
根据上式,符合要求。
4、模具结构的设计
4.1型腔布局
根据生产的要求和塑件的外形可设计成一模两腔的布局,平衡布置,这样模具尺寸
较小,制造方便,生产成本低,布置如下:
4.2分型面的设计
模具设计中,分型面的选择很重要,它决定模具的结构复杂程度,需要考虑的因素
也比较多,由于分型面受到塑件在模具中的成型位置、浇注系统设计、塑件的结构工艺
及精度、嵌件位置形状以及推出方法、模具制造、排气、操作工艺等多种因素的影响,
因此在分型面的选择要综合分析比较,从中选择最佳的方案。选择分型面一般要遵循以
下几项原则:
(1)分型面应选在制件外形最大轮廓处;
(2)分型面的选择要便于制件顺利脱模,尽量使制件在开模时留在动模一边;
(3)分型面的选择要保证制件的精度要求,满足模具加工制造工艺;
(4)分型面的选择不要影响模具排气和抽芯机构。
综上,分型面选取如下图:
4.3浇注系统
4.3.1主流道设计
主流道的端面与喷嘴接触多做成半球形的凹坑,两者应严密地结合,避免高压塑料
熔体溢出,凹坑球半径R2应比喷嘴球头半径R1大1-2mm。主流道小端直径应比注塑机
喷嘴孔直径约大0.5-1mm,常取Ø4-8mm,视制品大小及补料要求决定。大端直径应比
分流道宽度大1.5mm以上,其锥角不宜过大,一般2°—6°。内壁有Ra=0.2-0.4μm
以下的粗糙度,在内壁研磨和抛光时应注意抛光方向,不能形成垂直于拔出方向的划痕,
否则会发生脱出困难,加工腐蚀性材料还应将流道内孔镀铬。该模具R2=11mm,小端
直径为Ø5mm,大端直径为Ø6mm。
4.3.2分流道设计
分流道设计时有以下原则:
(1)尽量保证各型腔同时充满,并均匀的补料,以保证同模各塑件的性能、尺寸尽可能一致。
(2)各型腔之间的距离恰当,应有足够空间排布冷却水道、螺钉等、并有足够的截面积承受注塑压力。
(3)在满足以上要求的情况下尽量缩短流道长度、降低浇注系统凝料重量。
(4)型腔和浇注系统投影面积的重心应尽量接近注塑机锁模力的中心。一般在模板的中心上。
分流道常见断面形状有圆形。正六边形、梯形、U形、半圆形、矩形等数种,希望
选取易加工、且在流道长度和流道面积相同的情况下流动阻力和热量损失都较小的单面形状。从减少热损失的角度出发,其比表面积(即单位体积所具有的表面积,约等于断面周长与断面面积之比)应越小越好;从减少流动阻力的角度出发,也有类似的结论。通过比较该模具选择梯形端面分流道。因成型材料是POM,为避免表面疵痕,必须对流道表面仔细抛光。查得POM的分流道直径约为3.2-10mm,该处选择4mm,平衡式分布。
4.3.3主流道衬套的设计
由于主流道与注塑机的高温喷嘴反复接触与碰撞,所以设计成独立的主流道衬套,选用优质钢材制作并经热处理提高硬度。主流道衬套要求承受交变应力,其外圆盘直径不能太大,以避免肩部弯矩过大,配合段的直径亦不宜过大,以免注入模内的塑料产生过大的反压力,使主流道衬套后退,甚至将连接螺钉拉断。
4.3.4定位环的设计
为节省加工作量和材料,将定位环和衬套分开设计。
4.3.5浇口设计
浇口直接与塑件相连,把塑料熔体引入型腔。浇口浇注系统的关键部位,交口的形状和尺寸对塑件质量影响很大,浇口在大多数情况下是整个流道中断面尺寸最小的部分,流动阻力大,对充模流动起着控制作用,冷却时最先冻结。常见的浇口形式有边缘浇口、扇形浇口、平缝浇口、圆环浇口、轮辐浇口、爪型浇口、点浇口、潜伏式浇口、护耳浇口、直浇口等十种。
该设计采用潜伏式浇口,这种浇口进料部分一般选在制件侧面和背面隐蔽处,不致影响制品的外观,而且在开模时容易实现自动切断,制品上残留浇口痕迹很小,,所以顶出制品时自动去凝料。
4.3.6冷料井的设计
由于注塑机喷嘴和冷模具接触降温,致使喷嘴前端常存有一段低温料,为除尽这段冷料,在主流道对面开设冷料井,使冷料不进入分型面和型腔。本设计才有倒锥形冷料井,分模时靠倒锥起拉料作用,然后再强制推出,由于主流道无需横向移动,故容易实现自动脱模。
4.4成型零件的结构设计
构成模具型腔的零件统称为成型零件。由于型腔直接与高温高压的塑料相接触,它的质量直接关系到制件质量,因此要求它具有足够的强度、刚度、硬度、耐磨性,以承受苏丽哦的挤压力和料流的摩擦力,有足够的精度和较低的表面粗糙度,以保证塑料制品表面光亮美观、容易脱模。
4.4.1定模型芯
4.4.2动模型芯
4.4.3型腔设计
4.5侧向分型
侧向分型用于有外侧凹的塑件,系将凹模做成两瓣或者多瓣,利用侧向分型完成各瓣与塑件之间分离,脱出测凹。
4.5.1侧向分型的方式
机械侧向分型,最典型的是斜导柱分型,这种机构的特点是经济合理、动作可靠易实现自动化操作。
4.5.2抽拔距的计算
最小抽拔距
S1=36mm
设计抽拔距 S=S1+(2~3)mm
S=38mm
4.5.3斜销计算
斜销的角度 α=20°
斜销有效长度
L1=111mm
斜销的直径 Ø10~40mm,该设计d=Ø20mm D=d+5mm=25mm
斜销总长
L2=151.14 mm
开模行程 H=Scotα=Lcosα=104 mm
4.5.4导滑槽
导滑槽与滑块是动配合,要求运动平稳,不宜过松,亦不宜过紧,一般采用T形导
滑槽,设计时使滑块与滑槽上下左右各有一个面相配合(动配合H8/f7)其余面之间则
留出0.5-1mm的间隙。
4.5.5楔紧块
当塑料熔体注入型腔后,它以很高的压力作用于瓣合模块,迫使滑块后退,其作用
力等于塑料压力和沿滑动方向塑料作用在型芯或模板上投影面积的乘积。由于斜销的刚
强度较差,故用楔紧块来承受这一侧向推力。
楔紧块的斜角应略大于斜销斜角,这样开模时楔紧块的小面能很快离开滑块,不会
发生干涉现象,它一般比斜销角大2°-3°。
本设计中将楔紧块与定模型芯固定板做成一个整体,增加强度。
4.5.6滑块
本设计中型腔即是它的滑块
4.5.7滑块定位装置
分型抽芯结束后,当滑块与斜销相互离开时,滑块必须停留在刚刚分离的位置上,
以便合模时斜销能顺利地重新进入滑块的斜孔,为此必须设滑块定位装置。本设计中采
用挡块定位。
4.6模架的选择
塑件大小约为80×70×90,查GB/T12555-2006根据模架A2535进行修改。
4.7推出机构
使用8ר6mm的推杆推出,每个塑件使用四根均布的推杆。
4.8导向机构
4.8.1动定模导向
4.8.2推板导向
4.9排气系统
为了在注塑过程中将型腔内原有的空气排出,常在分型面处开设排气槽。本设计中
在动定模接触面开设了1mm深的排气槽。
4.10冷却系统的设计
冷却系统的设计原则包括:
(1)冷却水道的设置应均匀的布置在动定模和型腔四周;
(2)冷却水孔的孔间距越小,直径越大,则对塑件冷却越均匀;
(3)水孔与相邻型腔表面距离相等;
(4)采用并流流向,加强浇口处的冷却。
1 题名(宋体 四号 粗体)(段前、段后0.5行)
说明:章、节编号全部顶格排,编号与标题之间空1个字的间隙。
×××××××××××××××××××××××××××××××××××
××××××××××××××××××××××××××××××(宋体 小四号)
1.1 题名(宋体 小四号 粗体)(段前、段后0.5行)
×××××××××××××××××××××××××××××××××××
××××××××××××××××××××××××××××××(宋体 小四号)
图1(或图1.1)(图的编号和图题应置于图下方)(居中 宋体 五号 粗体)
说明:图应具有“自明性”,即只看图、图题和图例,不阅读正文,就可以理解图意。
表1(或表1.1)(表的编号和表题应置于表上方)(居中 宋体 五号 粗体)
说明:①表应具有“自明性”。
②表的编排采用国际通行的三线表。
③如某个表需要转页接排,在随后的各页上应重复表的编号。编号后跟表题(可省略)和“(续)”,置于表上方。
④续表均应重复表头。
w1 = u11 - u12u21..........................................................................................................(1)(或1.1)
说明:①论文中的公式应另起行,并缩格书写,与周围文字留足够的空间区分开。
②公式的编号右端对齐。
③较长的公式需要转行时,应尽可能在“=”处回行,或者在“+”、“-”、“×”、“/”等记号处回行。
1.2 题名(宋体 小四号 粗体)(段前、段后0.5行)
1.2.1 题名(宋体 小四号 粗体)(段前、段后0.5行)
××××××××××
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