【作者】 张振；

【导师】 朱元吉；

【作者基本信息】 合肥工业大学 ， 机械电子工程， 2008， 硕士

【摘要】 为适应塑料异型材市场对挤出模具高速稳定的要求,改善模头中几何形状复杂的功能块流道设计依赖于经验,常常造成模头挤出不稳定的现状,本文根据聚合物流变学原理,以有限元软件ANSYS为平台,采用数值模拟方法对于异型材的功能块、拐角等复杂部位的挤出模头流道结构进行了全面的研究。针对功能块流道形状复杂的特点,以两个典型的功能块实例进行研究,分别代表了出口平均流速大于和小于异型材主框的两种功能块类型,以模头出口各部分平均速度相一致为评价标准,结合挤出模头实践中各种可能的结构形式,通过模拟计算,选择合适的功能块流道设计方案。并引入最优化设计理论,对所选方案中的功能块流道结构的关键参数进行优化设计。并且,以出口平均流速差值的波动幅度为流道稳定性的判定依据,作流道结构的稳定性选择。对于外壁主框流道的拐角等特殊部位,依照实际模头的习惯做法,进行结构参数的优化设计,并对优化结果进行稳定性评价,为外壁拐角流道结构的合理设计提供更加合理的选择。本文得出的一些结论和方法,将模头中功能块、拐角等复杂部位流道结构设计中的经验做法,提升到以聚合物流变学为理论基础的,通过数值模拟计算进行的优化设计方法之中,求得更加合理的结构参数,这不仅可以知道挤出模头的稳定性设计,而且也为实际制造中的试模和修模工作指出了方向,可以最大限度的减少经验的局限性给挤出模具的稳定作业留下的隐患。更多还原

【Abstract】 In order to adapt the plastic profile market’s requests of high speed and stability for the extrusion die,we should improve the situation that the design of sprue runner in the extrusion tooling for extrusion forming the complex geometry functional part of plastic profiles was used to depend on experiences, in which the instable operation often occurred during the process of extrusion. A study was made on the rating design of the sprue runner by using ANSYS software and based on the design criteria that every subregion of profile in the outlet section of extrusion die has equal average flow velocity. A method for the numerical value design was proposed , which was used to simulate the sprue runner structure of the complex geometry functional part and corner of plastic profiles.For the complex geometry functional part of a die, the flow fields of two typical functional part flow channels were simulated by using ANSYS. We chose a best design suitable for the manufacturing processes ,and combining the finite element numerical analysis method with the optimizing method ,the main parameters of the functional part were optimized. Then, choose the best sprue runner structure according to the difference of average flow velocity in the outlet section of extrusion.For the corner and the point of intersection of the main sprue runner of a die, an estimation criteria , the subregion of different kinds of sprue runner in the outlet section of extrusion die has equal average flow velocity, was provided by different kinds of design of different kinds of sprue runner.The conclusions and methods got in the paper are very valuable for not only improving the stability design of the complex geometry sprue runner in the extrusion tooling, but also the adjustment and repairing of the dies.更多还原