注射成型模具设计英文文献和中文翻译(7)
As mentioned earlier, geometry such as battery cover is normally known to have dissimilar shrinkage rate with respect to width and height. In order to evaluate the effect of selected variables quantitatively, the ratio of the averaged deformation rate with regard to height and width defined as Eq. (18) has been compared for battery cover
Figure 7 shows the relative magnitude of main and interaction effects of the selected variables on yb in Eq. (18) based on design matrix in DOE. Here, ci stands for the main effect of each variable shown in Table 2. The other ones represent the interaction effect of two or more variables associated with each index, i.e., c12 is for the interaction between mold temperature and Young’s modulus. As shown in Fig. 7, the inpidual effect of Poisson’s ratio is biggest, while Young’s modulus has the smallest effect in case of battery cover.
Fig. 7 Relative magnitude of main and interaction effects for
battery cover
The inpidual effect of each variable can be expressed visually as shown in Fig. 8. The slope of yb as a function of Poisson’s ratio is steepest while slope of yb as a function of Young’s modulus is most gradual. The interaction effect of mold temperature and Poisson’s ratio or one of Poisson’s ratio and thermal expansion coefficient cannot be negligible, since their value is quite bigger than the inpidual effect of Young’s modulus and similar to the main effect of cooling time. It is concluded that Poisson’s ratio could be one of the key variables to deal with if there exists a problem related with dissimilar shrinkage rate regarding width and height.
Fig. 8 Inpidual effect of (a) mold temperature, (b) Young’s modulus, (c) Poisson’s ratio, (d) thermal expansion coefficient, and (e) cooling time
For front cover, the relative magnitude of inpidual and interaction effects of variables on yf (see Eq. (19)), which represents the deviation between deformation rate at upper and lower position along the height, is plotted in Fig. 9.
Figure 9 shows that Poisson’s ratio has the largest inpidual effect again and the main effect of cooling time is the second largest. Especially, Poisson’s ratio affects significantly than others, while mold temperature shows the almost negligible effect. We also noticed that Poisson’s ratio could be one of the key variables to deal with the problem related with dissimilar shrinkage along the height. In order to solve the existing problem, choosing material with the appropriate range of Poisson’s ratio could be one of the solutions. From this, DOE results could provide the useful guide to handle problems when final deformation by injection molding has an issue.
注射模成型广泛应用于大批量生产多种尺寸和复杂形状的移动装置零件的制造业。然而，最终质量，尤其是尺寸或形状，指原始设计规范不总是令人满意源于耕种各样的原因。本研究旨在开发数值模型的最终质量预测和随后确定存在问题的关键原因。模流分析软件和有限元分析软件同时被用来模拟塑料从模具里喷射后注塑成型过程和热变形产生过程。为了验证该模型，变形预测的模型与实验结果进行比较，两者的结果显示出良好的一致性。我们还进行了实验设计（DOE）研究不同工艺参数对注塑成型制品的最终变形的影响。源于实验设计的开发的模型和信息将有望为移动设备设计的初始阶段提供有用的资源。
关键词：注塑，实验，数值分析，热变形设计，残余应力,论文网
1 介绍
由高分子材料生产零部件的注塑成型过程是关键制造技术之一。材料被送入加热的桶，混合，并被迫进入模腔内，在那里它冷却下来并固化到所述腔体的具体结构。由于有可能产生在短时间内大量复杂的零件，它被广泛用于生产制造部件被组装于各种工程设备，包括移动电话。一般零件从注塑过程经历了大范围的温度变化，异质材料部件造成翘曲的异种收缩率可能是由热变形引起的。这些现象可以导致如组件，最终实现拆卸零部件的尺寸差的缺陷。为了减少在注射成型过程中的有缺陷的产品，其他的最终热变形关键因素的区分是一个非常重要的问题。控制它们的最佳处理条件应提高生产率并降低了制造成本。
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