【作者】 刘云；

【导师】 叶升平；

【作者基本信息】 华中科技大学 ， 材料加工工程， 2015， 硕士

【摘要】 覆膜成型作为V法铸造技术的关键环节,EVA铸造薄膜成型能力好坏与厚薄,将对铸件表面的光洁度和尺寸精度有着直接影响。随着V法铸造技术的广泛应用,形状结构较复杂的零件也开始使用V法造型技术,随之而来的是对超薄V法铸造EVA薄膜的各项力学性能提出了更高的要求。基于华中科技大学与北京永生运佳包装材料有限公司合作项目,本文研究了铸造EVA薄膜性能的影响因素并以此为国产EVA薄膜的改进提供理论基础。根据V法铸造工艺对EVA塑料薄膜的各项力学性能的要求,对薄膜的性能指标包括常温力学性能,热成型性以及耐烘烤性等进行测试,通过数据对比中日薄膜的性能差别并分析原因。通过EVA薄膜力学性能理论值的对比后,将国产EVA薄膜与日本薄膜在不同类型模具上进行覆膜对比实验以验证改进效果:首先是对表面形状复杂的零件,由其覆膜表现可以得出两者在生产过程中强度和延伸性的差异;其次是表面精细度要求较高的工艺品零件,这就要求薄膜厚度尽可能薄,热塑应力小,薄膜保持成型形状。通过对比筛选后,将性能最佳的EVA铸造膜通过V法厂家的生产试用来检验其稳定性。根据所测的实验对比数据,改进后的国产0.06mm超薄EVA铸造膜在拉伸比较大的复杂模具和精细度要求较高的工艺品上的覆膜表现与日本薄膜相当,其力学性能、热成型性能上在国产超薄铸造膜领域取得了突破性进展并成功用于国内多家V法铸造厂家且有效地降低了生产所使用的铸造膜厚度。更多还原

【Abstract】 As the key material of the V-process casting, V-process casting EVA plastic film,s forming ability and thickness has a direct impact on the smoothness and dimensional precision of casting. With the wide application of V-process casting technology, even complex structure parts are also starting to use this technology, accompanied by a higher requirements for the V-process casting EVA films,mechanical performance.Based on the cooperation between Huazhong University of Science and Technology and Beijing Yongsheng Yunjia packing material Co. Ltd., the influencing factors of casting EVA films, properties are researched and use it as a basis to improve the performance of EVA casting plastic films. According to the requirements of the V- process casting on the performance for EVA plastic film, the paper do the research on every performance index of the film including extensibility, thermal forming, baking resistant and so on. Through the comparison between Chinese and Japanese films according to the data obtained, we can analysis the reason of difference and supply the suggestions for improvement.The comparison between the domestic improved EVA film with Japan plastic film in practice with different molding is necessary after the theoretical value comparison: the first is that for the complex structure parts, this comparison can exhibit its difference of strength and extensibility; the second is for the high surface,s precision parts, which requires the film as thin as possible, small thermoplastic stress and maintaining its shape after molding. And then verify its stability through tryout of V-Process foundry.From a series of comparative data, the improved Beijing EVA film make a breakthrough in 0.06 mm ultrathin film,s field. Its mechanical properties, thermal forming property improved a lot than before; and its coating performance in complex mold and arts with high precision surface mold reveals that there is no significant different with Japanese film. And it is applied in domestic V-process casting foundry successfully with thinner thickness.更多还原