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基于数值模拟的长型热喷嘴热平衡分析及优化设计
The thermal equilibrium analysis and optimization design of long hot nozzle based on numerical analysis
【作者】 尚新才;
【导师】 黄诗君;
【作者基本信息】 广东工业大学 , 材料科学与工程, 2012, 硕士
【摘要】 近年来热流道注射技术已经在汽车、通讯、家电、医疗和日用品等领域得到广泛的应用,有着巨大的成本优势,产生了明显的经济效益,但热流道技术在生产过程中还面临一些问题。首先是结构的限制不能直接对热喷嘴浇口进行加热,只能由热喷嘴本体通过热传导的方式供热,导致热喷嘴浇口处的温度会比本体温度偏低;其次浇口与相对低温的模具相接处,导致大量的热损失,引起浇口处温度的降低。较低的浇口温度会影响注射成型的制件质量,对温度敏感的塑料材料尤其突出,为此必须对热喷嘴的结构、发热丝布置等进行优化,特别是对长型的热喷嘴。本论文基于现代计算机技术的热分析软件,建立计算机仿真模型,运用CAE分析平台ANSYS Workbench对热喷嘴的整个加热过程进行数值仿真,模拟热流道长型热喷嘴的整体加热温度场,分析影响整个热喷嘴温度场热均衡的因素,对各种加热结构的热喷嘴进行模拟分析和实验测量。根据模拟分析和实验测量的数据总结长型热喷嘴在加热过程中的温度场与加热丝缠绕的关系,优化热喷嘴尤其是长型热喷嘴的加热结构设计。论文首先对生产中遇到的个案(汽车保险杠)进行模拟分析,验证和评估CAE分析在热流道系统以及热喷嘴温度场中应用的可行性。通过对汽车保险杠的热喷嘴分析及改进,知道CAE分析能基本反映热喷嘴的温度场分布情况,为热流道的设计、生产以及制造提供一定的指导和帮助。对热喷嘴进行一般情况的模拟,探索热喷嘴在加热过程中的温度场与加热丝的功率、缠绕方法、结构形式以及热喷嘴与模具接触等各种因素的关系。对诸多因素逐项进行分析,并且用实验来验证模拟分析的结果以及模拟结果和实验数据之间的差别,探索影响整个热喷嘴温度场的主要因素,从而改进热喷嘴的结构设计。目前,热流道在国内的应用比较多,但是对其理论的研究相对较少,导致国内的热流道模具供应商提供的大多是低端产品,产品特色和自主知识产权相对缺乏,国内的热流道模具市场被欧美发达国家的少数制造商垄断的局面一直没有改观。本文通过对热流道的温度场进行CAE分析,探索热流道加热结构的设计,指导热喷嘴结构的设计,具有一定的实际应用价值。
【Abstract】 In recent years hot runner injection techniques has been widely used in areas such as automotive, telecommunications, home appliances, medical treatment, and daily necessities, with a huge cost advantage, resulting in significant economic benefits, but the hot runner technology are still facing some problems in the production process. The first the hot nozzle gate can not be heated directly because the structural limitations, only by the hot nozzle body heat conduction heating, leading to the gate of the hot nozzle temperature than the low body temperature; second the gate next to the mold of the relatively low temperature, resulting in a lot of heat loss, causing the temperature of the gate to low. The lower gate temperature will affect the quality of the injection molding part, especially important to temperature-sensitive plastic materials, so it must be to optimize the thermal structure of the nozzle and the heating coil set, especially the long hot nozzle.This thesis is based on thermal analysis software with modern computer technology, the establishment of a computer simulation model, the use of CAE analysis platform-ANSYS Workbench numerical simulation on the whole heating process of the hot nozzle, obtaining the long hot runner nozzle whole heating temperature field and analysis the entire thermal affects fact of the nozzle temperature field to thermal equilibrium, Finally simulation analysis and experimental measurements on a variety of heating the thermal nozzle structure. According to the simulation analysis and experimental measurement data, summary of the temperature field of the long hot nozzle and the heating wire winding the relationship during the whole heating process, optimizing the thermal nozzle structure, especially long hot nozzle heating structure design.Firstly, by one case that the production (car bumper) simulation analysis, validation and evaluation the feasibility of the application CAE analysis to the hot runner systems and hot nozzle temperature. Analysis and improvement of through bumper thermal nozzle, to prove CAE analysis can basically reflect the hot nozzle temperature distribution, to provide some guidance and help for the design, production and manufacture of hot runner.By the simulation of the general situation hot nozzle, explore the relationship in between the power of heating coil, the winding method of the heating wire in the whole heating process of the hot nozzle, the structure form of the hot nozzle, hot nozzle in contact with the mold and other factors with the temperature field. Many factors one by one, by experiments to test the difference between the simulation analysis of the results of the simulation results and experimental data, to explore the main factors to affect the hot nozzle temperature field, thus improving the thermal design of the hot nozzle structure.At present, the hot runner has been widespread use in the country, but relatively few studies about their theory, the domestic hot runner suppliers provide mostly low-end products, the relative lack of product features and independent intellectual property rights, the domestic situation that hot runner products market has been monopolize by the few manufacturers of American and European countries has not changed. This article explore the structural design of hot runner heating hot runner temperature field and guide the design of the hot nozzle structure by CAE analysis, with some practical value.
【Key words】 Hot spray nozzle; CAE; Thermal analysis; Bumper; Hot runner;