This paper presents a framework for optimizing injection molding process parameters for minimum product cycle time subjected to constraints on the product defects. Two product defects, namely, volumetric shrinkage and warpage, as well as seven process parameters including injection speed, injection pressure, cooling time, packing pressure, mold temperature, packing time, and melt temperature, were considered. Injection molding experiments were conducted on specifically chosen test points and results were used to compute the volumetric shrinkage and warpage (at each test point). Thereafter, three relationships between the product cycle time (one relationship), the two product defects (two relationships), and the injection molding parameters were constructed using the kriging technique. An optimization problem to minimize the product cycle time (described by the first relationship) subject to constraints on the product defects (described by the latter two relationships) was then formulated. A combination set of points between the lower and upper extreme values of acceptable product defect was generated to serve as constraints for the two product defects. The optimization problem was then solved using the Fmincon function, available in the Matlab optimization toolbox. A plot of the optimization results revealed an appreciable tradeoff between the cycle time and the two product defects. To validate the optimization, an additional injection molding experiment was conducted for one of the optimization results. Results from the additional experiment showed reasonably close agreement with simulation optimization results differing in the cycle time, the warpage and volumetric shrinkage by 6.7%, 3.2%, and 8%, respectively.

中文翻译：

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基于实验的注塑成型工艺参数优化以缩短产品周期

本文提出了一种优化注塑工艺参数的框架，以在产品缺陷约束下实现最小产品周期时间。考虑了体积收缩和翘曲两种产品缺陷，以及注射速度、注射压力、冷却时间、保压压力、模具温度、保压时间和熔体温度等七个工艺参数。注塑实验在专门选择的测试点上进行，结果用于计算体积收缩率和翘曲（在每个测试点）。此后，使用克里金技术构建了产品周期时间（一种关系）、两种产品缺陷（两种关系）和注塑参数之间的三种关系。然后制定了一个优化问题，以最大限度地减少受产品缺陷约束（由后两个关系描述）的产品周期时间（由第一个关系描述）。生成可接受产品缺陷的下限值和上限值之间的组合点集作为两个产品缺陷的约束条件。然后使用 Fmincon 函数求解优化问题，该函数在 Matlab 优化工具箱中可用。优化结果图显示了周期时间和两个产品缺陷之间的明显权衡。为了验证优化，对优化结果之一进行了额外的注塑实验。