【作者】 刘东雷；

【导师】 辛勇；

【作者基本信息】 南昌大学 ， 材料加工工程， 2010， 博士

【摘要】 高光无痕注射成型(Rapid Heat Cycle Molding, RHCM)技术的提出源于客户对高精端产品品质的追求,又以其精密、高效、节能、绿色环保等技术优势而得以迅速发展。目前该技术已经在实际生产中得到很好的应用,相对于生产经验,其成型理论的研究则较为匮乏和滞后,本研究正是针对这一现状,采用成型实验与数值模拟并重之方法,对高光无痕注射成型工艺技术方面作一些开拓性的应用基础研究工作,以期为高光产品、高光模具的设计与开发,以及高光成型工艺的制定与优化等提供理论上的指导。研究了高光无痕注射成型数值模拟技术。根据高光无痕注射成型“高温、快速”的工艺特点,提出合理的简化与假设；将熔体填充和保压阶段看作统一的可压缩填充过程,由流体力学基本定律推导出与广义Hele—haw平面流动模型相一致的连续性方程、动量方程和能量方程,给出与之相适应的边界条件；以Rabino-Witsch模型为基础,推导了熔体粘度随成型压力变化关系式,得出因压力增大而引起熔体粘度相应增加的粘度修正因子,据此对Cross_WLF模型进行修正以更客观描述熔体粘弹行为；采用双域Tait方程描述熔体填充状态,实现了高光无痕注射成型过程数值模拟。研究了确保高光制品与模具型腔高精确复合的结构设计技术,以及确保能够对介质温度做出快速且均衡响应的高光模具结构设计技术；对模具结构尤其是型腔设计做以大胆创新,自主开发了以随行介质通道和直通式水路接入口为主要结构特征的车载高光蓝牙模具；简要介绍了以J11-W-160型模温机为核心的模具温度控制辅助系统的工作原理。研究了温度因素对高光无痕注射成型制品残余应力的影响。从连续性方程、动量方程和能量方程出发,以线性、小变形、热弹模型Duhamel-Neumann方程为基础,推导了高光无痕注射成型冷却过程制品残余应力(应变)与降温速度和降温梯度的关系式,从理论上分析了温度因素对制品残余应力的影响。研究了模具温度在快速升温和降温交变温差条件下的对制品品质的影响。以制品对型腔复原性能、成型收缩、成型翘曲和表面沉降等为品质考核指标,采用成型实验与数值模拟并重的方法,通过人为引入干扰因子的方法保证模拟结果具有更高的客观性,研究并得出了模具温度在快速升温和降温交替变化条件下对制品品质的影响效应与影响规律,相同及不同模具温度条件下其他成型参数,诸如熔体温度、注射压力、保压压力、保压时间和冷却时间等,对制品品质影响效应及影响规律,以及在保证相同成型品质条件下,各成型参数随模具温度的变化规律,且实验结果与理论分析得到较好的吻合。研究了高光无痕注射成型工艺优化技术。以车载高光蓝牙产品为例,以中心复合实验法(center composite design, CCD)进行实验规划,引入信噪比(signal-to-noise, S/N)理论、熵值权重法(Entropy-Based Weight, EBW)与顺序偏好法(Technique for Order Preference by Similarity Ideal Solution, TOPSIS)等数据处理技术,从数理角度处理实验数据使之能客观反应制品品质状况；利用响应曲面法(Response Surface Methodology. RSM),并结合方差分析(analysis of variance, ANOVA)和误差分析建立了成型工艺预测模型；针对传统遗传算法的不足之处提出改进算法(Improved Genetic Algorithm, IGA)实现了工艺预测模型的寻优过程,并经生产实验验证该工艺优化技术具有很好的适用性,给出了一种可用于指导生产实践的可行高光无痕注射成型工艺优化方法。更多还原

【Abstract】 Rapid Heat Cycle Molding (RHCM) technology, developed from the high-precision product quality pursuit of customers, and for its precision, high efficiency, energy saving, environmental protection and other technical advantages to flourish. RHCM technology has already been in actual production well applied currently, and considerable success. Relative to production experience, the theoretical research is more scarce and hysteresis. In response to current research situation, this study has made a pioneering fundamental research work in process using experiment and numerical simulation methods. And the purpose is to give some theoretical guidance on high-gloss products, high-gloss mold design and development, and process determination and optimization etc.The numerical simulation technology of RHCM is studied. Based on the process characters of RHCM technology, suitable hypothesis and reduction are introduced. Considering melt filling and packing stages as uniform compressible process, the mathematical models of continuity, momentum and energy equation, have been derived based on the theory of polymer rheology theory, which is similar to Hele-Shaw model. And the corresponding boundary conditions are defined. The relation of melt viscosity with pressure changed is derived based on Rabino-Witsch equation, a viscosity correction factor is obtained. Thus a modified CrossWLF model is obtained, which can more objective description viscoelastic behaviors of polymer melt in filling process. Coupling with the Tait model to describe melt filling status, the numerical simulation of RHCM is realized ultimately.The high-gloss part, as well as the high-gloss mold, structure design technology is investigated, which can ensure products reaching to a high-precision replication with the cavity, and the temperature of mold cavity varied with the medium in timely and evenly. Then a vehicle-used high-gloss bluetooth mold, with following media path and straight through type media inlet, is independent innovated. And then a mold temperature control auxiliary system is introduced, especially the core devise of J11-W-160 type mold temperature control machine. The influence of temperature factor in Rapid Heat Cycle Molding on thermal stress maintained in part is researched. Based on continuity, momentum and energy equation, coupling with linear, infinitesimal, thermoelasticity Duhamel-Neumann equation, the relation between the thermal stress and temperature factor in cooling stage of RHCM is reached. Thus the influence tendency of temperature factor on residual thermal stress is analysis in theory.The influence of mold temperature on part quality is investigated, which is heated or cooled in the fast alternating conditions. The replication of part to cavity, shrinkage, wrapage and sink of part are considered as quality evaluation indexes. By integrating the experimental and numerical simulation method, as well as interference factors technology, this thesis investigates and come to the influence effect and impact law of mold temperature on product quality. It also studies and come to the influence effect and impact law of other parameters on product quality under fixed or changed mold temperature conditions, as well as the changing law of others with mold temperature under the same product quality presumed conditions. And the experimental results and the theoretical analysis are in good agreement.The RHCM process optimization technology is investigated. In this paper, the center composite design (CCD) method is employed in arranging the experimental points. And the samples qualitative data is processed to more objective response the products quality by integrating signal-to-noise (S/N) method, Entropy-Based Weight (EBW) method, Technique for Order Preference by Similarity Ideal Solution (TOPSIS), etc. Then a predictive response surface model (RS) for comprehensive quality index is created using Response Surface Methodology (RSM) based on analysis of variance (ANOVA) method. The RS model is interfaced with an effective improved Genetic Algorithm (IGA) to find the optimum process parameters values. And the actual production achieves good result, which shows that the process control technology is feasible and effective on processing quality optimization of high-gloss plastic part.更多还原