【作者】 张果；

【导师】 李倩；

【作者基本信息】 郑州大学 ， 材料加工工程， 2013， 硕士

【摘要】 注射压缩成型是在普通注射成型技术的基础上发展起来的一种新型的塑料成型加工方法。该成型方法因压缩阶段的引入降低了注射压力和制品的残余应力,特别适用于加工光学性能要求较高的制品。聚碳酸酯(PC)作为一种常用的透明热塑性工程塑料,因其具有优异的抗冲击性以及良好的透光率而被广泛应用于航空航天以及汽车、家电等众多的领域中。采用普通注塑成型聚碳酸酯制品往往容易产生由于残余应力过大导致的制品开裂问题,利用注射压缩成型技术可以很好地解决这些问题。在注射压缩成型过程中,影响制品质量性能的因素很多,如产品结构设计、模具设计、材料的结构性能以及工艺参数的设置等。其中,工艺参数的设置对制品的质量性能的影响较为显著。如果仅仅通过实验不断调整成型工艺参数的设置则需要耗费大量的人力物力并且延迟开发周期,因此借助于数值模拟计术研究工艺参数对制品质量的影响规律具有重要的意义,可以为实际生产提供一定的指导。本文以聚碳酸酯角窗制品为研究对象,结合数值模拟与试验设计方法研究了注射压缩成型工艺参数对制品质量性能的影响,以期为实际的生产提供指导作用。主要工作内容与结论如下：(1)首先,利用CAD软件对聚碳酸酯角窗制品进行建模,并在moldflow软件中建立角窗制品的浇注系统和冷却系统的有限元模型并对所建模型进行初步分析。以模内残余应力、翘曲变形量、体积收缩率结果为评价指标对比了注射压缩成型和普通注射成型工艺,结果表明：采用注射压缩成型工艺可以获得翘曲变形量较小,收缩较均匀、残余应力较小的聚碳酸酯角窗制品。(2)以聚碳酸酯角窗制品脱模后残余应力和翘曲变形总量为质量指标,采用Taguchi正交试验设计方法研究了熔体温度、模具温度、压缩距离、延迟时间等7个工艺参数对两质量指标的影响规律。通过极差分析分别得到两质量指标的最佳工艺参数组合；通过变量分析得到各因素对质量指标的影响度排序。结果表明：工艺参数对两质量指标的影响度排序是相同的,但是各工艺参数对两质量指标的影响程度不同。在所考察的7个工艺参数中,熔体温度、延迟时间、压缩距离对两质量指标的影响较为显著。进一步采用单因素试验的方法研究这三个主要工艺参数对两质量指标的影响规律,结果表明：随着熔体温度的升高,延迟时间的减小以及压缩距离的减小,浇口位置单元处沿厚度方向上的各层残余应力均逐渐降低；翘曲变形随着熔体温度的增加,延迟时间的延长和压缩距离的减小而减少。(3)在正交试验的基础上,采用部分析因设计法研究了主要工艺参数间的一级交互作用对两质量指标的影响。结果表明：影响两质量指标的交互作用的排序不同,但是延迟时间和压缩距离的一级交互作用均对两质量指标的影响最大。(4)采用相同的试验设计方法和数据处理方法研究工艺参数对于体积相同同曲率不同的平板制品、角窗制品以及等曲率的1/4球壳三制品的残余应力和翘曲变形量的影响规律。结果表明：所考察的7个工艺参数对三个制品的残余应力以及翘曲变形的影响度不同；其中熔体温度均是影响三制品两质量指标的最主要的工艺参数,并且随着制品曲率的增加,熔体温度对两质量指标的影响度也随之增加；除熔体温度外,延迟时间和压缩距离对三制品两质量指标的影响也较为显著。更多还原

【Abstract】 Injection compression molding processes is a advanced type of plastic manufacturing technologies compared with injection molding process. Low residual stress and low injection press can be realized with this technologies. Due to this advantages of injection compression molding, it is increasingly possible to substitute the injection molding processes in case of optical product. Polycarbonate (PC),one of the commonly used transparent thermoplastic engineering plastics, has excellent impact resistance and good light transmittance. Due to this advantages, it is wildly used in aerospace and automotive, home appliance and so on. When it comes to producing the PC products, the traditional injection molding method usually induce many defects, such as large Warping deformation and large residual stress. However, injection compression molding can solve the above problems very well. During the injection compression molding process, there are many factors which can affect product quality performance, such as the product structure design, mold design, material performance and the combinations of process parameters. In these factors, the affect of combinations of process parameters is remarkable. In order to get excellent quality product, we have to adjust the combinations of process parameters. But it is difficult to adjust only by the experiment since it require numerous case studies as well as much time and cost. In order to reduce such efforts and expenses, computer simulations for injection compression is utilized in this paper. Computer aided engineering analysis has supported useful research in the molding processes with better efficiency.The effect of process parameters on PC product in injection compression processes is studied by using the design of experiment (Taguchi DOE) and numerical analysis. DOE is designed and applied progressively for process design. The results can provide certain reference for the industrial injection compression process of PC products. The main work and conclusions are as follows:(1) Firstly, the product mold is set up by CAD software and then the finite elim-ent model of the feed system and cooling system is built by moldflow software. Based on this, the injection compression simulation of PC product is done to confirm the correctness of the model. The injection compression molding simulation and traditional injection molding are done under the same conditions. Compared with the result s of the two methods, the results show that a better PC product with low warping deformation, low residual stress and uniform shrinkage can be got by injection compression.(2) The effect of processes parameters on the Z component warping deflection and the residual stress is investigated by using the Taguchi design of experiment and numerical analysis. The processes parameters include melt temperature, mold temperature and compression distance and compress delay time and so on. Then the analysis of means(ANOM) is performed for various process conditions in order to determine the optimum combination of process parameters. The analysis of variance (ANOVA)is applied to identify the influence degree order of the process parameters for the two test indexes. The results show that the influence degree order for the two test indexes is same, but the effects of various process parameters on the two test index are at different levels. Among the various process parameters, the influence of melt temperature, compress delay time and compression distance is the most significant. In order to further study the influence of the main three process parameters, the single factor analysis is utilized on the basis of the optimum combination of process parameters. The results show that the residual stress near the gate location is gradually reduced with the increase of melt temperature, the decrease of compression distance and delay time. When it comes to the Z component warping deflection of the PC product, it will reduce with the increase of melt temperature and compress delay time, but it will increase with the increase of compression distance.(3) On the basis of orthogonal experiment, the fractional factorial experiment is designed to investigate the two-way interactions of the main process parameters. The results show that the effect of the two-way interactions of the main process parameters on the two test index factors is different, but the interaction between the compress delay time and the compression distance is the most important factor.(4) With the same design of experiment method and data processing method, the effect of processes parameters on the Z component warping deflection and the residual stress of three kinds of injection compression molded products with the same volume and different curvature is investigated. The results show that the effect order of process parameters for each product is different and melt temperature is the most important factor. With the increase of curvature, the effect of melt temperature is also increase. In addition to the melt temperature, delay time and compression distance also have significant effect.更多还原