锥形塑料件注塑模设计doc 42页正式版.docx
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锥形塑料件注塑模设计doc42页正式版
广西工学院鹿山学院
毕业设计(论文)
题目:
锥形塑料件注塑模
系别:
专业班级:
姓名:
学号:
指导教师:
职称:
二〇一一年五月二十七日
摘要
本文是关于锥形塑料件注塑模的设计,主要内容包括塑件的成形工艺分析,模具结构形式的确定,分型面位置的确定,浇注系统的形式和浇口的设计,成形零件的结构设计和计算,模架的确定和标准件的选用,合模导向机构的设计,脱模推出机构的设计等。
在正确分析塑件工艺特点和PP材料的性能后,涉及模具结构、强度、寿命计算及熔融塑料在模具中流动预测等复杂的工程运算问题;运用CAD、UG等不同的软件分别对模具的设计、制造和产品质量进行分析。
锥形塑料件注塑模设计,采用一般精度,利用CAD、UG来设计或分析注射模的成型零部件,浇注系统,导向部件和脱模机构等等。
综合运用了专业基础、专业课知识设计,其核心知识是塑料成型模具、材料成型技术基础、机械设计、塑料成型工艺、计算机辅助设计、模具CAD/CAM/CAE等。
关键词:
模架;标准件;脱模推出机构
Synopsis
Thispaperisaboutthedesignofplasticinjectionmold,cone-shapedincludeplasticpartsformingprocessanalysis,determinationofdiestructureform,partingsurfacepositioning,gatingsystemformsandrunnerdesign,formingpartsstructuredesignandcalculation,thedeterminationoftheformworkandstandardpartschoose,shutthemoulddesignofsteeringmechanism,strippingoutinstitutiondesign,etc.
InthecorrectanalysisplasticstechnologycharacteristicsandPPmaterialperformance,involvingthemouldstructure,strength,lifetimecalculationandmoltenplasticmouldflowpredictionincomplexengineeringcomputationproblem;UsingCAD,suchdifferentsoftwareUGrespectivelytomoldofdesign,manufacturingandproductqualityanalysis.Taperedplasticinjectionmolddesign,usegeneralaccuracy,useCAD,UGtodesignoranalysisofinjectionmold,gatingsystem,discussesguidecomponentsandmouldingmechanism,etc.Comprehensiveuseoftheprofessionalbasis,professionalclassdesign,anditscoreknowledgeisplasticmolding,materialmoldingtechnologybase,mechanicaldesign,plasticinjectionmoldingprocess,computeraideddesign,mouldCAD/CAM/CAD,etc.
Keywords:
formwork;standardparts;strippingoutinstitutiondesign
1.绪论························································1
2.塑件分析·························································4
2.1塑件设计要求················································4
2.2塑件结构分析·················································5
2.3塑件原材料分析················································5
2.4计算塑件的体积和质量··········································6
3.注塑成型的工艺参数················································7
3.1注塑成型的工艺参数············································7
4.拟定模具结构形式·················································8
4.1确定型腔数量及排列方式········································5
4.2模具结构形式的确定···········································8
5.注射机选用·······················································9
5.1注塑机简介···················································9
5.2注塑机基本参数···············································9
5.3注射机的选用原则············································10
5.4选择注射机··················································10
5.5注射压力的校核··············································11
5.6由注射机料筒塑化速率校核型腔数量n···························11
5.7按注射机的锁模(合模)力的校核·······························11
5.8模具厚度校核···············································12
6.分型面的选择····················································13
6.1分型面的设计原则············································13
7.浇注系统设计·····················································14
7.1浇注系统设计原则···········································14
7.2主流道设计··················································14
7.3主流道尺寸···················································14
7.4浇口套设计···················································15
7.5分流道的设计·················································15
7.6分流道的形状及尺寸···········································16
7.7分流道的表面粗糙度···········································16
7.8分流道的布置·················································16
7.9浇口的设计···················································16
7.10浇口位置选择的原则··········································16
7.11浇口的选用··················································17
7.12浇口结构尺寸的经验计算······································17
7.13浇注系统的平衡··············································17
7.14冷料穴······················································18
7.15拉料杆的设计················································18
7.16浇注系统凝料的脱出机构······································18
7.17排气方式···················································18
8.成型零部件设计··················································20
8.1整体式凹模、凸模结构·········································20
8.2组合式凹、凸模结构···········································20
8.3成型零部件的工作尺寸计算····································20
8.4型腔径向尺寸的计算··········································20
8.5型芯径向尺寸的计算··········································21
8.6型腔高度尺寸的计算··········································21
8.7型芯高度尺寸的计算··········································22
8.8成型零部件的工作尺寸计算····································22
8.9组合式矩形型腔侧壁厚度的计算································22
8.10组合式矩形型腔底板厚度的计算·······························22
9.结构零部件的设计················································24
9.1模架的确定和标准件的选用····································24
9.2合模导向机构的设计··········································25
9.3导向机构的分类··············································25
9.4导柱导向机构设计要点········································25
9.5导柱的设计·················································26
9.6导套的设计·················································26
10.推出机构的设计··················································27
10.1推出力的计算···············································27
10.2按模具中的推出零件分·······································27
10.3推管推出机构··············································28
10.4推管的固定与配合···········································28
11.温度调节系统的设计············································29
11.1求单位时间(每分钟)内注入模具中的塑件质量M··················29
11.2求冷却水的体积流量·········································29
11.3求冷却管道直径d···········································30
11.4求冷却回路总传热面积A····································30
11.5冷却水回路设置的基本原则··································30
11.6冷却系统的结构·············································30
12.模具材料的选择·················································32
12.1塑料模零件选材原则········································32
12.2模具材料的选用············································32
13.装配图························································33
14.结束语··························································34
15.致谢··························································35
16.参考文献·······················································36
绪论
1.1模具在加工工业中的地位
模具是利用其特定的形状去成型具有一定的形状和尺寸制品的工具。
在各种材料加工工业中广泛的使用者各种模具。
据统计,在现代工业生产中,60%~90%的工业产品需要使用模具,模具工业已经成为工业发展的基础,许多新产品的开发和研制在很大程度上都依赖于模具生产,特别是汽车、摩托车、轻工、电子、航空等行业尤为突出。
而作为制造业基础的机械行业,根据国际生产技术学会的预测,21世纪机械制造工业的零件,其粗加工的75%和精加工的50%都将依靠模具完成。
因此,模具工业已经成为国民经济的重要基础工业。
模具工业发展的关键是模具技术的进步。
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成为衡量一个国家制造水平的重要标志之一。
世界上许多国家,特别是一些工业发达国家都十分重视模具技术的的开发,大力发展模具工业,积极采用先进技术和设备,提高模具制造水平,并且取得了显著地经济效益。
不论在经济繁荣时期还是在经济萧条时期,模具工业都不可或缺。
经济发展快时产品畅销,自然要求模具能跟上;而经济发展滞缓时期,产品不畅销,企业必然千方百计开发新产品,这样同样会对模具带来强劲需求。
因此,模具工业别称为不衰的工业。
目前,世界模具市场仍供不应求,近几年,世界模具市场总量已超过700亿美元,其中美国、日本、法国、瑞士的够一年出口模具约占本国模具总产值的1/3。
因此研究和发展模具技术,提高模具技术水平,对于促进国民经济的发展有这特别重要的意义。
美国工业界认为“模具工业是美国工业的基石”,日本吧模具誉为“进入富裕社会的原动力”,德国则冠之为“加工工业中的帝王“,在欧美其他一些发达国家,模具被称为“磁力工业”。
由此可见模具工业在各国国民经济中的重要地位。
1.2塑料模具在模具行业中的重要性
塑料模具是当今工业生产中利用特定的形状,通过一点的方式呈现塑料制品的工艺设备或工具,它属于型腔模的范畴。
通常情况下,塑件质量的优劣及生产效率的高低,其模具因素约占80%。
然而模具的质量还坏有直接与模具的设计与制造有很大的关系。
随着国民经济领域的各个部门对塑件的品种和产量需求愈来愈大,产品的更新换代俞来愈短,用户对塑件的质量要求愈来愈高,因而对模具设计与制造的周期和质量提出了更高的要求,这就促使塑料模具设计和制造技术不断向前发展,从而推动了塑料工业以及机械加工工业的高速发展。
1.3塑料模的现状及发展趋势
在塑料成型生产中,先进的模具设计、高质量的模具制造、幼稚的模具材料、合理的加工工艺和现代化的成型设备等是成型优质塑件的重要条件。
一副优良的的注射模模具可以成型上百万次,这与上述因素有很大的关系。
中国塑料膜工业从起步到现在,历经了半个多世纪,有了很大的发展,模具水平有了很大的提高,在大型模具方面已能生产48″(约122cm)大屏幕彩电塑壳注射模具,6.5KG大容量洗衣机全套塑料模具以及汽车保险扛个整体仪表盘等塑料模具,精密塑料模方面,已能生产照相机塑料件模具,多型腔小模数齿轮模具及塑封模具。
经过多年的努力,在模具CAD/CAE/CAM技术,模具的点加工和数控加工技术,快速成型与快速制造急速,新型模具材料等方面取得了显著进步;在提高模具质量和缩短模具设计制造周期等方面做出了贡献。
尽管我国模具工业有了长足的进步,部分模具已达到国际先进水平,但无论是数量还是质量仍满足不了国内市场的需要,每年仍需进口10多亿美元的各类大型,精密,复杂模具。
与发达国家的模具工业相比,在模具技术上仍有不小的差距。
如下表:
从塑料成型模具的设计理论、设计实践和制造技术出发,塑料成型技术大致有以下几个方面的发展趋势:
(1)推广塑料膜CAD/CAE/CAM技术的集成化
21世纪模具CAD/CAM的基本特征是高度集成化、智能化、柔性化和网络化。
追求的目标是提高产品质量及生产效率,缩短设计及制造周期。
降低生产成本,最大限度地提高模具制造业的应变能力,满足用户的需求。
下图是CAD/CAE/CAM集成化的工作流程图:
(2)加强塑料模标准化应用
模具标准化程度及标准零件的制造规模与范围,常可标志一个国家的工业化程度。
使用标准模架及标准零件,可节省金属材料30%降低成本25%对于模具工业的发展具有十分重要的战略意义。
(3)大力发展快速模具制造技术,缩短模具制造周期;随着先进制造技术的不断出现,模具的制造水平也在不断地提高,基于快速成形的快速制模技术,高速铣削加工技术,以及自动研磨抛光技术将在模具制造中获得更为广泛的应用。
(4)发展优质模具材料和采用先进的热处理和表面处理技术,优质的模具材料和先进的表面处理技术的使用可以有效的提高模具的使用寿命、塑料制件成型质量和降低加工成本等。
2、塑件分析
塑件的分析是对所要成型的产品有个初步的了解,在接受设计任务书以后就要对塑料的品种、批量的大小、尺寸精度与技术条件,产品的功用及工作条件有个整体概念,以便在设计模具时优选各种方式来成型塑件。
仔细阅读塑件制品零件图,从制品的塑料品种,塑件形状,尺寸精度,表面粗糙度等各方面考虑注塑成型工艺的可行性和经济性,必要时,要与产品设计者探讨塑件的材料种类与结构修改的可能性。
2.1塑件及塑件材料的特点
本设计塑件是工厂提供,本产品是一个锥形塑料件。
如图所示
1.材料名称:
聚丙烯(PP)
2.生产纲领:
中小批量生产
3.尺寸精度:
一般精度
聚丙烯的分子结构为典型的主体规整结构,为结晶聚合物,其分子量为10~50万,密度为0.9~0.91g/cm³成型收缩率:
1.0~2.5%成型温度:
160~220℃。
特点:
无毒无味,密度小,强度、刚度、硬度耐热性均优于低压聚乙烯,可在100°左右使用。
具有良好的电性能高频绝缘性不受湿度的影响,但低温时变脆,不耐磨、易老化。
适于制作一般机械零件,耐腐蚀零件和绝缘零件。
常见的酸见有机溶剂对它几乎不起作用,可用于食具。
成型热性:
1.吸湿性小,易发生融体破裂,长期与热金属接触易分解。
2.流动性好,但收缩范围及收缩值大,易发生缩孔,凹痕,变形。
3.冷却速度快,浇注系统及冷却系统影缓慢散热,并注意控制成型温度,料温低温高压是容易取向,模具温度低于50°时塑件不光滑易产生熔接痕,90°以上易发生翘曲变形。
4.塑料壁厚须均匀,避免缺胶,尖角,以防应力集中。
2.2塑件结构分析
(1)、开模方向
由零件的三维图分析,外表面的表面质量是比较重要的,再根据模具的结构分析得到,产品的外表面应该在定模上,在产品的分型面设置推出机构,所以开模方向应沿零件的Z轴。
(2)、收缩率
PP的收缩率为1.0%~2.5%,在设计本产品时,结合产品的结构工艺特点和材料的特性,在本设计中,零件的收缩率为1.5%。
(3)、零件壁厚
本产品的壁厚设置为1.0mm,是根据零件的工作要求、摆放位置和PP的化学和流动特性确定的。
(4)、脱模斜度
根据产品的外型,结合产品的工作条件、工艺特点,为提高产品的生产效率和表面质量,脱模斜度设置为1°。
(5)、圆角
塑件在面与面之间都设计了圆角过渡,这样不仅可以避免塑件尖角处的应力集中,提高塑件强度,而且可以改善物料的流动状态,降低充模阻力,便于充模。
(6)、塑件尺寸精度分析
2.3、影响塑件尺寸精度的因素
①和模具直接有关系:
模具的形式或基本结构;模具的加工制造误差;模具的磨损、变形、热膨胀。
②和塑料有关的原因:
塑料的标准收缩率的变化;塑料的成型收缩、流动性、结晶化程度的差异;再生塑料的混合、着色剂等添加剂的影响;塑料中的水分以及挥发和分解气体的影响。
③和成型工艺有关的原因:
由于成型条件变化造成的成型收缩率的波动;成型操作变化的影响;脱模顶出时的塑料变形,弹性恢复。
④和成型后实效有关的原因:
周围温度、湿度不同造成的尺寸变化;塑料的塑性变形及因为外力作用产生的蠕变、弹性恢复;残余应力、残余变形起的变化。
(7)塑件的尺寸公差
本塑件在使用上不需要采用高精度等级,但为了不影响塑件的美观,也不能采用低精度等级。
同时,考虑到该材料的性能和成型工艺特点,经查表《模具设计与制造手册》,精度等级选为3级。
2.3计算塑件的体积和质量
计算塑件的体积和质量是为了选用注塑机,提高设备利用率,确定模具型腔数。
经UG计算塑件体积为:
(塑件密度取0.90g/cm3)
体积V=2738.6960mm3
曲面面积S=2897.1369mm2
质量M=2.465g
3、注射成型工艺
注射成型工艺过程包括成型前的准备、注射过程和塑件的后处理三个部分。