Adaptive Adjustment of Injection Molding Process for Mechanical Characteristics Using the Taguchi Method and Response Surface Methodology

This study is analyzed variations of mechanical characteristics that depend on the injection molding techniques during the blending of short glass fiber (SGF) and polytetrafluoroethylene (PTFE) reinforced polycarbonate (PC) composites. Planning of experiment is based on a Taguchi orthogonal array table, and applied signal-to-noise ratios to determine an optimal setting. Simultaneously, applying response surface methodology (RSM) analysis, a mathematical predictive model of the tensile strength and flexural strength properties of mechanical characteristics were developed in terms of the injection molding process parameters. In addition, analysis of variance (ANOVA) also was applied to identify the effect of process parameters of SGF and PTFE reinforced PC composites for the tensile strength and flexural strength. Additional runs were conducted in order to validate the optimal setting and compare the performance of Taguchi method and RSM approach.     

Optimization of Mechanical Characteristics of Short Glass Fiber and Polytetrafluoroethylene Reinforced Polycarbonate Composites via D-Optimal Mixture Design

This paper deals with the application D-optimal mixture design (DMD) integrating response surface methodology (RSM) to discuss variation of mechanical characteristics depending on injection molding during production of short glass fiber (SGF) and polytetrafluoroethylene (PTFE) reinforced polycarbonate (PC) composites. Planning of experiments was based on a D-optimal mixture design (DMD). By applying RSM analysis, a mathematical predictive model of the tensile strength and flexural strength properties was developed in terms of the mixture ratio of PC, SGF, and PTFE. In addition, analysis of variance (ANOVA) and response surface graphs were applied to identify the effect of mixture ratio of SGF and PTFE reinforced PC composites for the tensile strength and flexural strength.     

基于DOE、RSM及PSO的大尺寸板类塑件的翘曲优化

首先通过实验设计（DOE）分析得出对柜式空调面板翘曲变形影响较大的工艺参数为熔体温度、模具温度、保压压力和保压时间。其次,以这4个工艺参数为实验变量,以面板的翘曲量为目标,采用响应面法（RSM）构建出两者之间的二阶响应面模型,并优化出翘曲量最小的工艺参数,翘曲量预测误差率仅为2.486 %,模型精度较高。最后,运用粒子群算法（PSO）对二阶响应面模型进行迭代寻优,得出最优工艺参数。验证结果表明,PSO优化误差为4.882 %,相比于RSM优化,翘曲量实际值由5.217 mm降为3.459 mm,降低了38.367 %,优化效果较好。     

基于响应面模型和遗传算法的注塑工艺多目标优化

结合Taguchi试验设计,利用注塑成型计算机辅助工程（CAE）模拟软件Moldflow对不同工艺参数下的注射成型进行模拟分析,对成型塑件体积收缩率、翘曲变形及缩痕指数3个目标进行综合评判;建立综合评分与工艺参数关系的代理模型——响应面模型,然后结合遗传算法进行全局多目标优化寻优,获得最优工艺组合,并进行模拟验证。结果表明,建立的响应面模型是可靠的,利用响应面模型进行注塑工艺多目标优化是一种有效的方法。     

Integrated simulation to predict warpage of injection molded parts

Injection molding analysis programs were developed for CAE (Computer Aided Engineering) in injection molding of thermoplastics. The programs consist of mold cooling, polymer filling-packing-cooling, fiber orientation, material properties and stress analyses. These programs are integrated to predict warpage of molded parts by using a common geometric model of three dimensional thinwalled molded parts. The warpage is predicted from temperature difference between upper and lower surfaces, temperature distribution, flow induced shear stress, shrinkage, and anisotropic mechanical properties caused by fiber orientation in the integrated simulation. The integrated simulation was applied to predicting warpage of a 4-ribbed square plate of glass fiber reinforced polypropylene for examination of its validity. Predicted saddle-like warpage was in good agreement with experimental one.     

微孔发泡注射成型与传统注射成型的对比分析

通过微孔发泡注射成型和传统注射成型定量对比分析,系统分析了两种成型在翘曲变形、体积收缩、残余应力、温度场分布等方面的本质区别,并基于流变学理论,揭示了微孔发泡注射成型的成型机理。结果表明,微孔发泡注射成型的翘曲变形、残余应力、成型压力和成型时间明显小于传统注射成型的,且微孔发泡注射成型的翘曲变形和残余应力随着开始发泡的熔体预填充体积分数减小而减小,微孔发泡注射成型的熔体温度在浇口附近低于传统注射成型熔体温度,而在远离浇口处则要高。     

某轻量化稳定杆吊杆注射成型方案优化设计

针对采用玻璃纤维增强聚酰胺和注塑工艺制备的轻量化稳定杆吊杆,考虑了其承载特点对成型工艺的要求。在此基础上,通过设计浇口位置和数量,对其进行注射成型工艺方案设计。结合有限元分析结果,对比3个浇口方案的纤维取向、熔接痕、翘曲变形等方面的成型质量,选择满足成型性能要求的浇口方案。然后,以翘曲变形量为优化目标,对选定的浇口方案进行正交试验,得到良好的注射成型工艺优化参数,在此工艺参数下优化翘曲值为1.514 mm。最后,为保证稳定杆吊杆承载性能,需要对成型工艺条件及模具设计做出调整。     

微孔塑料注射成型制品体积收缩与翘曲变形数值分析

采用Moldflow软件，通过微孔注射成型过程的数值模拟，系统研究了熔体注射温度、模具温度对其体积收缩、翘曲变形和残余应力的影响规律，并基于流变学理论，揭示了其影响机理。研究结果表明，随着熔体注射温度和模具温度增加，微孔注射制品翘曲变形和残余应力均增加，成型制品的体积收缩随着熔体注射温度升高而增加，而随着模具温度升高而减小。本研究为微孔注射成型工艺和模具的设计提供理论指导。     

非对称温度场下微孔发泡模内表面装饰复合成型工艺的翘曲变形

以拉伸试验样条为研究对象,采用正交试验设计与流动仿真计算,对非对称温度场下微孔发泡模内表面装饰复合成型工艺（MIM/IMD）中制品翘曲的影响因素进行分析,获取翘曲变形最小的最佳工艺参数组合。并对4种注射成型工艺（MID/IMD、IMD、MID、CIM）分别在X、Y、Z方向的翘曲变形仿真结果进行对比,分析不同成型工艺的翘曲变形在不同方向上的变化、泡孔半径及密度,探究微孔结构及分布对翘曲变形的影响规律。结果表明,熔体温度210 °C、注射速率55 cm³/s、充填体积98 %、超临界N₂浓度0.2 %（质量分数）、冷却时间40 s时,翘曲最小,翘曲变形最大减少3.414 mm;采用发泡工艺对制品的翘曲有一定的抑制作用;非对称温度场导致覆膜侧的泡孔尺寸及密度大于非覆膜侧,且温度较非覆膜侧高,使样条覆膜侧收缩变形慢于非覆膜侧,从而导致样条两侧产生具有向非覆膜侧内凹卷曲趋势的不均衡翘曲变形。     

Residual thermal stresses in injection molded products

Nonisothermal flow of a polymer melt in a cold mold cavity introduces stresses that are partly frozen-in during solidification. Flow-induced stresses cause anisotropy of mechanical, thermal, and optical properties, while the residual thermal stresses induce warpage and stress-cracking. In this study, the influence of the holding stage on the residual thermal stress distribution is investigated. Calculations with a linear viscoelastic constitutive law are compared with experimental results obtained with the layer removal method for specimens of polystyrene (PS) and acrylonitrile butadiene-styrene (ABS). In contrast to slabs cooled at ambient pressures, which show the well-known tensile stresses in the core and compressive stresses at the surfaces, during the holding stage in injection molding, when extra molten polymer is added to the mold to compensate for the shrinkage, tensile stresses may develop at the surface, induced by the pressure during solidification.     

基于RBF神经网络和遗传算法的注塑成型质量控制与预测

针对注塑产品容易产生翘曲和缩痕的问题,以某检测仪外壳为研究对象,运用RBF神经网络模型和遗传算法,对注塑成型质量进行控制与预测。基于正交试验方案,运用Moldflow有限元分析软件获得试验结果;利用样本数据建立试验因素与响应值之间的RBF神经网络模型,并用最优拉丁超立方抽样技术,获得样本点对模型精度进行检验;运用带精英策略的非支配排序遗传算法(NSGA-Ⅱ)对注塑成型工艺参数进行多目标优化,达到有效控制和预测翘曲变形、体积收缩率和缩痕指数的目的,并经模拟和试模验证误差较小。结果表明,运用RBF神经网络模型和遗传算法对注塑成型质量进行控制与预测,生产出检测仪外壳最大翘曲变形量为0.394 mm,外观无缩痕。     

高光三色汽车尾灯灯罩注塑工艺参数优化

以高光三色汽车尾灯灯罩作为研究对象,使用Box-Behnken设计(BBD)方法并通过Design-Expert软件建立塑件总翘曲量及第一射收缩率与注塑参数的响应模型,并检验响应模型的精确度及可信度。运用此模型进行注塑工艺参数优化,得到最小总翘曲量和最小第一射收缩率,应用最佳参数进行注塑过程模拟;进行试生产得到了变形量小、质量较好的产品。     

汽车储物盒导轨的翘曲变形分析及改进

汽车储物盒导轨注塑时易发生翘曲变形,通过对导轨局部翘曲变形的原因分析,结合注塑的特点,提出了改进方案;考虑材料的分子排列聚集态及功能特性对翘曲变形的影响,选择聚甲醛（POM）材料;采用正交试验设计方法,以导轨的成型工艺参数：模具温度、注射时间、保压压力和冷却时间为实验因子,翘曲变形量为实验目标,运用Moldflow软件对试验方案进行模拟分析,得到导轨的最优成型工艺参数,注塑结果表明,导轨在x向和z向翘曲变形量均已控制在0.5 mm以内,满足生产要求。     

Modeling and simulation of thermally induced stress and warpage in injection molded thermoplastics

Thermally induced stress and the relevant warpage caused by inappropriate mold design and processing conditions are problems that confound the overall success of injection molding. A visco-elastic phase transformation model, using a standard linear solid for the solidified polymer and a viscous fluid model for the polymer melt, of 2-D finite element scheme with 8 noded overlay isoparametric elements was used to simulate and predict the residual stress and warpage within injection molded articles as induced during the cooling stage of the injection molding cycle. Computed results are in good agreement with published experimental data. The approach proposed here is to examine and simulate the injection molding solidification process with the intent of understanding and resolving more inclusive and realistic problems.     

注塑工艺参数对聚碳酸酯车灯面罩翘曲变形的影响

采用正交实验方法,利用Moldflow软件对汽车的车灯面罩进行注塑模拟,系统地分析了注塑中熔体温度、模具温度、注射时间、保压压力和保压时间等工艺参数对聚碳酸酯（PC）车灯面罩翘曲变形的影响规律和机理,并确定了车灯面罩的最佳工艺参数值。将所确定的最佳工艺参数导入Moldflow软件进行分析,发现车灯面罩的翘曲变形量明显下降。     

基于计算机仿真的注塑成型工艺优化研究

为了优化注塑成型工艺,研究了注塑成型的数学模型,以及产生翘曲形变的原因,在此基础上利用Moldflow软件对薄壁件塑料注塑成型过程中的宽浇口平板进行了仿真实验,并采用了无定型塑料丙烯腈-丁二烯-苯乙烯共聚物+聚碳酸酯(ABS+PC)对其进行注射、保压、冷却等流程模拟,选定了保压压力、熔体温度、冷却时间、模具温度、注射时间、保压时间等主要工艺参数,并通过方差比较的方法对这些工艺参数进行了评价,最终确定了注塑成型的优化方案。通过实验得出了ABS+PC的最优工艺参数组合,有效降低薄壳制件的翘曲量并优化了其制品性能。     

采用RFR-GA算法的薄壁注塑件质量多目标优化

汽车内饰件可由注塑加工获得,但成型过程中塑件产生的翘曲、体积收缩较大,针对该问题,以某汽车薄壁注塑件为例,研究了其注塑工艺参数的优化方法.通过以注塑过程中的最小翘曲和最小体积收缩率为目标函数,以注塑温度、模具温度、注射压力、保压压力、保压时间以及冷却时间等参数作为设计变量,构建了多目标全局优化模型.利用Moldflow...     

薄壁塑件注射成型工艺参数优化

在注射成型过程中将计算机模拟技术和实验优化设计相结合,以相机外壳为例利用MoldFlow对各工艺参数进行注射成型过程的模拟.通过分析塑件体收缩变形和翘曲变形的原因,得出熔体温度是影响塑件体收缩变形的主要因素,而保压压力对翘曲变形起主导作用力.并在正交试验的指导下优化工艺参数,使收缩率和翘曲变形分别降为原来的75.9%和87.0%.     

薄壳多孔塑料件高光注射成型工艺研究

对手机壳体塑料件进行了常规注射成型CAE研究,分析存在较为严重的表观质量问题。通过采用高光成型技术,以沉降指数、体积收缩率和翘曲变形为质量指标,利用正交试验和多目标综合平衡法分析研究得出该产品的最佳成型工艺参数组合。分析结果表明,高光注射成型技术在改善薄壳多孔塑料件缺陷方面比常规注射成型有着更大的优越性。     

Review on the Effects of Process Parameters on Strength,Shrinkage, and Warpage of Injection Molding Plastic Component

Injection molding process causes differences between designed shape and real parts, all of them associated to shrinkage and warpage phenomena. Temperature, pressure distribution, and other injection parameters during molding process originate local shrinkage and the internal stresses depending on the relative stiffness of each part area. The aim of this work is to review and report the influence of injection molding process parameters on the postmolded strength, shrinkage, and warpage of injection molded parts. It is also to investigate the influence of injection molding process parameters on the postmolding shrinkage and warping of parts made of polypropylenes.