发布时间 : 星期五 文章自拍杆注塑模具毕业设计说明书更新完毕开始阅读a716159668dc5022aaea998fcc22bcd127ff4242
Design of injection mold for self timer
Abstract
In a variety of materials processing industry widely used in a variety of mold,Such as die-casting mold, molding metal forging mould, die casting；Glass mould, ceramic film, plastic film, etc. of forming non metal products.Each material forming die is divided into several types according to the molding method.
With high production efficiency, saving energy and raw materials, low cost, large quantity and other advantages, the use of mold production parts has the advantages of high efficiency, low cost, high cost and so on.Die forming has become an important means of modern industrial production, and become the most development potential of a variety of molding process.The level of mold industry is an important symbol to measure the level of a country's manufacturing industry, which determines the international competitiveness of the manufacturing industry of the country.Five pillar industries of the national economy -- machinery, electronics, automobile, petrochemical, construction are all required advanced mold industry and supporting.
From the point of view of use, the mold should be high efficiency, automation, easy to operate, especially when the plastic part of the larger, should try to reduce the mold and take part in the process of manual operation.To this end, often using automatic stripping, automatic side core pulling and other high efficiency automation of the mold, and even in the entire production process is completely no need to manually feed and take products of the automation of the mold.
From the production point of view, the processing technology of the mold parts is good, the material selection is reasonable, the manufacture is easy, the cost is low, and the assembly is convenient.
Key words: material processing mold automation
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第一章 塑件成型工艺性分析
第一节 塑件的分析
1.结构分析
塑件结构复杂程度一般，表面质量要求也较高。如图1-1所示，塑件的上端部需要侧抽芯一个孔，还有两个左右对称的加强筋。塑件的下端部需要用主型芯成型两个左右对称的孔。塑件外观质量要求高，外表面不允许出现划伤、气泡、缩孔、熔接焊等缺陷，综合考虑其浇注时的难易程度和成型特征等因素，浇口采用侧浇口。整体来看，该塑件成型较简单，脱模时包紧力较小，用推杆推出即可。
图1-1 工件
2.精度等级
根据塑件原料为ABS确定塑件公差等级为IT11。
3.脱模斜度
ABS属无定型塑料，成型收缩较小，选择脱模斜度为1o。
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第二节 ABS的性能分析
1.使用性能
综合性能良好，冲击韧度、力学强度较高，且在低温下也不迅速下降。耐磨性、耐寒性、耐水性、耐化学性和电气性能良好。水、无机盐、碱、酸对ABS几乎无影响。尺寸稳定，易于成型和加工。
2.成型性能
ABS为无定型塑料，其品种很多，各品种的机电性能及成型特性也各有差异，应按品种确定成型方法及成型条件。吸湿性强，含水量应小于0.3％，必须充分干燥，要求表面关泽的塑件应要求长时间预热干燥。流动性中等，溢边料0.04mm左右。易产生熔接焊，模具设计时应注意尽量减小浇注系统对斜流的阻力，模具设计时要注意浇注系统，选择好进料口位置、形式。ABS在升温时粘度增高，塑料上的脱模斜度宜稍大，宜取1o以上。在正常的成型条件下，壁厚、熔料温度及收缩率影响极小。
3. ABS性能指标 其性能指标见表1-1
表1-1 ABS性能指标 密度g/cm 比体积/cm3·g-1 吸水率％ 熔点/o C 计算收缩率％ 比热容J·kg-1K-1 断裂伸长率％ 表面电阻率Ω
31.02~1.08 0.86~0.98 0.2~0.4 130~160 0.4~0.7 1470 35 1.2×1013 屈服强度/MPA 抗弯强度/MPA 抗压强度/MPA 抗拉强度/MPA 抗剪强度/MPA 拉伸弹性模量/MPA 体积电阻率Ω·m 滞流温度o C 50 80 53 38 24 1800 6.9×1014 130 第三节 ABS的注射成型过程及工艺参数
1.注射成型过程
1.1成型前的准备。对ABS的色泽、粘度和均匀度等进行检验，由于ABS的吸水性较大，成型前应进行充分的干燥。
1.2注射过程。塑件在注射机料筒内经过加热、塑化达到流动状态后，由模具的浇注系统静茹模具型腔成型，其过程可分为冲模、压实、保压、倒流和冷却五个阶段。
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1.3塑件的后处理。处理的介质为空气和水，处理温度为60~75，处理时间为16~20s。
2. ABS的注射成型工艺参数 2.1注射机：螺杆式。 2.2螺杆转速（r/min）:30。
2.3预热和干燥：温度（oC）为80-85,；时间（h）为3-4.。 2.4料筒温度（oC）：前段为180-200 中段为165-180 后段为150-170 2.5喷嘴温度（oC）：170-180 2.6模具温度（oC）：60-80
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