基于正交试验和MPI二次开发技术多目标优化注射工艺参数

工艺条件是影响注射成型制品质量的重要因素,采用CAF模拟软件进行注射成型的工艺优化不但能降低成本,提高效率,而且能提高注射制品的质量。本文通过MPI二次开发技术开发出注射成型工艺方案优选分析器,采用正交试验方法为用户提供多目标值下的最优工艺参数组合,进一步提高了工艺优化的效率,也为用户提供了实用方便的工艺优化工具。     

基于MPI的电脑机箱面板注射成型分析

以电脑机箱面板为实例,使用MPI软件对塑料件注射过程中的填充、冷却、翘曲情况进行模拟。分析了浇口位置、熔接痕分布、翘曲变形等情况,得到合理的浇注系统和注射工艺参数,减少了注射缺陷和塑料件变形。     

基于Moldflow/MPI的UPS电源壳体注塑成型分析

运用Moldflow/MPI模块对UPS电源壳体注塑成型过程进行了数值模拟分析,预测了熔体充模过程中的型腔压力分布、温度分布、锁模力大小、体积收缩率及翘曲变形;根据分析结果,提出了工艺优化方案,从而缩短模具设计制造周期。     

注射成型中保压曲线对制品表面质量的影响

在分析前人研究结果的基础上,总结出要获得较高表面质量的注塑制品需要两个条件:一是模腔压力值要大;二是模腔压力分布要均匀。利用Moldflow软件对矩形制品的注射成型过程进行了模拟。结果表明,采用先恒压后线性降压的保压曲线可以获得较大且分布均匀的模腔压力,故其成型的制品有较高的表面质量。     

反应注射成型及其制品性能和应用

介绍反应注射成型特点与原理,以及反应注射成型制品的性能与应用。     

冰箱零件的注射成型模拟

利用UGⅡ建立了冰箱盛物托盘零件的数学模型,并用Moldflow软件对其进行流动、保压、冷却过程模拟及翘曲分析,在有限元分析的基础上得到该零件注射成型的最佳工艺条件。研究表明:通过模拟计算,可最大限度消除产品设计、模具设计及制品成型过程中可能出现的不足,取代了传统的反复试模、修模等过程,从而降低产品制造成本,缩短产品开发周期。     

基于Moldflow的汽车安全气囊盖注射成型分析

以某汽车安全气囊盖的注射成型为例,介绍应用Moldflow软件进行CAE分析的步骤,通过填充、流动、冷却和翘曲等模拟分析,以期为模具开发过程中最佳浇口位置设置、流道系统布置、注塑参数优化和模具一次试模成功提供参考依据。     

基于Moldflow的汽车外饰件注射成型模拟与成型缺陷分析

以汽车外饰件前风挡下装饰板为研究对象,利用Moldflow软件,对其注射成型过程进行模拟,针对分析结果中预测可能出现的成型缺陷,提出相应的优化措施。最后将结果应用于该装饰板的模具型腔设计。结果表明,Moldflow在设计阶段可以找出产品可能出现的缺陷,提高一次试模成功率,从而降低生产成本,提高生产效率。     

基于Moldflow的汽车保险杠注射成型分析

利用Moldflow软件,采用扬子石化的汽车保险杠专用料高抗冲聚丙烯K9015,对威姿轿车前保险杠比例缩小模型进行了填充、保压、冷却以及翘曲模拟分析,讨论了2种浇注系统方案及产品产生翘曲变形的原因。结果表明,2种进胶方案的注射时间基本相同;采用3个浇口在一侧的进胶方案得到的制品外观质量更好,装配尺寸更合适;但2种进胶方案都会产生较大的翘曲变形,通过优化保压曲线可以减少制品的翘曲变形量。     

Moldflow在注射压缩成型中的应用

以厚壁圆盘为例,详细论述了Moldflow在注射压缩成型中的应用过程。通过模拟分析确定了浇注系统,得到了注射压缩成型厚壁塑料制品的最大注塑压力、缩痕分布情况、冷却时间和引起翘曲变形的主要因素,从而为注射压缩成型模具结构设计及工艺参数设置提供一定的指导。     

薄壁塑件注射成型翘曲变形的工艺优化

本文以注射成型照相机前壳为研究对象,以注塑成型中的翘曲量为优化目标,利用正交试验结合CAE模拟技术,研究模具温度、熔体温度、注射时间、保压时间、保压压力和冷却时间对制品翘曲的影响规律。用均值分析法得到最小翘曲变形的一组优化工艺参数组合,并进行CAE模拟验证。再运用方差分析确定各个工艺参数对翘曲变形的影响程度。     

薄壁塑件注射成型翘曲变形的工艺优化

本文以注射成型照相机前壳为研究对象,以注塑成型中的翘曲量为优化目标,利用正交试验结合CAE模拟技术,研究模具温度、熔体温度、注射时间、保压时间、保压压力和冷却时间对制品翘曲的影响规律。用均值分析法得到最小翘曲变形的一组优化工艺参数组合,并进行CAE模拟验证。再运用方差分析确定各个工艺参数对翘曲变形的影响程度。     

塑料制品注塑成型缺陷的成因分析

通过列举几种注塑成型过程中最为典型的几种缺陷,结合生产实际,从影响注塑成型制品质量的因素(产生的物理原因、注塑模具和制品结构、注塑工艺参数有关的原因、塑料材料)着手,分析了归纳注塑成型制品典型质量缺陷产生的原因,并提出了克服缺陷的具体改良措施。     

Modeling and experimental study of birefringence in injection molding of semicrystalline polymers

The prediction of birefringence developed in injection moldings is very important in order to satisfy required specification of molded products. A novel approach for the numerical simulation of the flow-induced crystallization and frozen-in birefringence in moldings of semicrystalline polymers was proposed. The approach was based on the calculation of elastic recovery that becomes frozen when the flow-induced crystallization occurred. The flow effect on the equilibrium melting temperature elevation due to the entropy reduction between the oriented and unoriented melts was incorporated to model crystallization. To find the entropy reduction and the frozen-in elastic recovery during crystallization, a non-linear viscoelastic constitutive equation was used. From the ultimate elastic recovery the crystalline orientation function was calculated. The crystalline and amorphous contributions to the overall birefringence were obtained from the crystalline orientation function and the flow birefringence, respectively. The birefringence profiles were measured and predicted in moldings of polypropylenes of different molecular weights obtained at various melt temperatures, injection speeds, holding times and mold temperatures. The resulting predictions were in fair agreement with corresponding experimental data.     

Rheological and thermal debinding behaviors of silicon nitride in powder injection molding

In powder injection molding process, it is important to analyze the rheological and thermal debinding behaviors of feedstock, because they can directly affect the final quality of products. Therefore, for the silicon nitride based feedstocks, the rheological and thermal debinding behaviors were investigated and compared between feedstocks prepared with the combination of two types of powders and sintering aid ratios. At first, the optimal solids loading for each feedstock was determined based on the results of the torque rheometer experiment. The viscosity of the feedstocks was measured using the capillary rheometer, and rheological properties were evaluated with the Power Law-Arrhenius model. Silicon nitride (JPN) feedstock with 5 wt% yttria and 2 wt% alumina (JPN+5Y2A) had the highest moldability index among all feedstocks. The powders with sintering aid ratio of 5 wt% yttria and 2 wt% alumina made the feedstocks have a high moldability index. Thermogravimetric experiment was also performed to analyze the pyrolysis behavior of the feedstocks, and the apparent activation energies for each feedstock were obtained using Kissinger method with the thermogravimetric analysis results. Based on the results, the master decomposition curve (MDC) was developed, and the utility of MDC for optimizing the thermal debinding process was verified.     

注塑成型异常分析及处理(二)

本文全面系统地针对注塑成型制件不满、收缩凹陷（缩水）和飞边（溢边、披锋、毛刺）、银纹、熔接痕等多种缺陷问题进行分析和阐述。主要从检查方法、原因分析、参数设定、制品设计与模具制造以及材料选择等方面。从现象到本质地分析制品产生缺陷的根本原因，进而提出有针对性地解决方案，将理论应用于生产变践中。     

Mechanical and morphological anisotropy in injection molding of thermotropic liquid crystalline copolyesters

Relationships among mechanical properties, degree of molecular orientation and molding conditions are investigated in injection molded plaques fabricated from a 4,4′-dihydroxy-α-methylstilbene (DHαMS)-based thermotropic liquid crystalline copolyester. Wide-angle X-ray scattering (WAXS) patterns reveal bimodal orientation states at most locations in the plaques. One population aligns roughly along the anticipated flow direction while a separate population is generated as a result of transverse stretching associated with diverging streamlines during mold filling. Micro-tensile bars are cut from the plaques both parallel and perpendicular to the filling direction to assess anisotropy in properties. Enhanced molecular orientation and properties ‘in-shear’ are observed for thinner plaques fabricated at relatively low mold temperatures and melt temperatures slightly above the nominal melting point of the polymer. Injection fill speed is not found to have a significant effect on anisotropy in tensile strength/stiffness. Mechanical properties such as tensile modulus and fracture stress are found to obey a ‘universal’ correlation with X-ray measurements of molecular orientation projected onto the axis of the testing specimens. These results suggest that even in the presence of complex, spatially heterogeneous orientation states, simple average measures of orientation can provide a robust means of anticipating macroscopic properties.     

Influence of feedstock preparation on ceramic injection molding and microstructural features of zirconia toughened alumina

Feedstocks for ceramic injection molding of ZTA containing 90 vol.% of sub-μm alumina and 10 vol.% of zirconia nanopowder were prepared by different processing techniques. Feedstocks were prepared by mixing in a sigma-blade kneader and subsequent homogenizing by twin-screw extrusion or shear roll compaction. Two other feedstocks were previously bead milled and subsequently processed by the same procedure. Compounding technology strongly influences the injection molding behavior and microstructures of the final product. Despite higher energy input of the shear roll compactor, powder agglomerates cannot be completely avoided. Pre-milling is effective to disperse and deagglomerate ceramic powders. Injection pressures of feedstocks from pre-milled powders were about 200 bar lower compared to pressures needed for non-milled feedstocks. Present feedstock preparation methods are feasible to produce homogeneous feedstocks, which strongly influence microstructures. In order to produce high solid loaded sub-μm/nm feedstocks, processing methods, pre-treatment and solid content have to be carefully chosen.