熔接痕性能评价的WSt模型及其验证

提出采用熔体汇合角度、流动前沿温度、压力三个参数来表征熔接痕,构建了评价熔接痕性能优劣的WSt模型,基于此模型对比了相同工艺参数下快速变模温成型(Rapid Heat Cycle Molding,RHCM)与普通成型的熔接痕质量,并以导风板为对象进行了生产验证.结果表明:快速变模温成型熔接痕的整体性能由普通成型的0.681提高到0.819,提高了20.3％;RHCM成型导风板熔接痕处的拉伸强度由普通成型的45.3MPa提高到53.8 MPa,强度提高了18.8％,与WSt模型所预测的20.3％接近.     

复杂塑料包装箱熔接痕疵病分析及工艺改进

目的 解决熔接痕疵病问题,降低废品率,提高生产效率。方法 通过熔接痕疵病成型机理及原因分析,采取在注塑模具上增加排气装置、改进分流道分布、增加冷却水道组数等工艺改进措施,改进后进一步优化注塑工艺参数。结果 工艺改进后,熔接痕疵病问题得以解决,产品质量提高,经过自由跌落工艺试验验证,工艺改进后加工的产品满足GJB 4403—2003和产品图样的相关要求,废品率由3%降低到0.78%以下,生产效率提高23%。结论 改进效果明显,解决了熔接痕疵病问题,提高了产品的外观质量,降低了废品率,保证了产品的使用性能,缩短了生产周期,也为今后生产提供了技术保障。     

基于翘曲的注塑成型工艺参数优化组合

采用Taguchi方法设计注塑成型模拟实验,以注塑成型工艺参数混合优化模块方法确定工艺参数最优组合。先建立注塑成型工艺参数混合优化模块,按L9(34)正交表进行实验,得到熔体温度、保压压力、注射时间、成型周期时间等参数不同水平时的翘曲和收缩率数据,翘曲量和收缩率都属于望小特性,计算出S/N比,通过S/N比反应图分析得出较优工艺参数组合,再实验验证确定最优组合,最后说明注塑成型工艺参数混合优化模块方法可行。     

蒸气辅助快速热循环注塑技术及模温响应模拟

快速热循环注塑采用动态模温控制新策略,可以彻底解决常规注塑工艺存在的短射、喷射痕、缩痕、流动痕、熔接痕、浮纤等缺陷。文中通过对快速热循环注塑工艺与常规注塑工艺的比较,深入研究了蒸气辅助快速热循环注塑工艺的原理,制定了相应的工艺流程,提出了一套新的利用蒸气加热和冷凝水冷却的动态模温控制方案。利用ANSYS模拟了快速热循环注塑工艺和常规注塑工艺的模温响应过程,分别获得了两种注塑工艺的模具加热速率和冷却速率,讨论了快速热循环注塑对塑件成型周期的影响规律。     

基于CAE耦合分析的注塑件熔接痕性能优化

采用Moldflow对注塑件的熔接痕进行CAE模拟,将Moldflow模拟注射成形后的结果数据导入到Algor中对制件做特征值屈曲分析,并将屈曲载荷因子作为注塑件熔接痕性能的评价指标。通过正交试验,分析了熔体温度、模具温度、保压压力、保压时间对制件屈曲载荷因子的影响。结果表明：熔体温度对熔接痕力学性能的影响最为显著,保压时间和模具温度次之,保压压力的影响最小。     

热流道计算机辅助工程(CAE)在洗衣机面板成型中的应用

热流道由于其多方面的优势而越来越被用于塑料的注射成型。文中以某款洗衣机面板为例,利用Moldflow软件对普通热流道和针阀式顺序注塑过程进行了优化模拟。通过对两者成型结果的定性分析和比较,可以得出,后者成型过程中,需要的最大注射压力和最大锁模力均小于前者成型的值,而制件的气穴和熔接痕的位置和数量明显优于前者成型的效果,制件总体质量和力学性能得到明显提高。同时也提出了顺序注塑模拟中应注意的问题。     

顺序控制技术在复杂塑料制品注射成型中的应用

采用传统热流道注射技术成型大型复杂的塑料产品,由于熔接痕数目多,使产品在涂装过程中频繁出现色兰.针对这一问题,提出了顺序控制注射技术的新方法,通过在原有注塑机上加装可控制的液压回路,实现多浇口顺序控制,从而减少或消除熔接痕.建立了某轿车前保险杠顺序控制注射成型数值模拟模型,运用控制机理及数值模拟技术,对其成型过程进行了分析.通过比较,表明采用顺序控制注射方法可以较好地控制大型注射产品成型中的熔接痕,生产试验验证所提出模型和方法的有效性和可靠性.     

高光大平板塑件熔接痕改善方法研究

高光塑件外观要求高,表面不能出现明显的熔接痕,而大型塑件大都是多浇口注塑不可避免的会产生熔接痕,如何减轻或消除大型塑件表面熔接痕,常用的模具及注塑解决方案都存在一定的局限,如成本高,不够节能环保,效果不佳等。本文在对高光产品常见成型方法进行分析比较的基础上,提出了一种更经济、节能环保的高光大平板塑件成型方法,可有效控制熔接痕。     

基于CAE的大型LCD注塑面板变模温设计与分析

研究了一种利用蒸汽加热和冷却水冷却的变模温注塑工艺,制定了其工艺流程.以LCD面板为例,通过构建变模温注塑工艺分析模型,利用ANSYS对其加热、冷却过程进行了数值模拟,研究了加热、冷却过程中型腔表面和聚合物熔体的热响应规律,为优化变模温注塑工艺参数提供理论依据.最后,通过构建LCD面板变模温注塑实验生产线,并将分析结果应用于实验生产,验证了模拟分析的有效性和准确性.结果表明,利用本工作提出的变模温注塑工艺,可在不降低生产效率的同时,彻底消除塑件表面熔接痕和提高塑件表面光泽度.     

局部加热技术在共混材料注塑工艺中的应用研究

实验证明采用局部加热技术对提高制什表面质量和品质，解决ABS、闪光铝共混材料制作产品注塑工艺中的熔接痕问题，不论在理论上，还是在实践中都是可行的。     

Improvement of mechanical properties of recycled plastic blends via optimizing processing parameters using the Taguchi method and principal component analysis

In this paper, the Taguchi method and principal component analysis (PCA) are used to improve the mechanical properties of recycled polypropylene (PP) blends in injection moulding procedure, with detailed assessments performed on each method and comparison was made based on results of both the methods. The experimental design was carried out by adopting a L9-3⁴ Taguchi orthodoxy array (OA), which has four controllable factors (i.e., melt temperature, mould temperature, injection speed and packing pressure) at three levels. Injection moulded specimens made from different compositions of virgin-recycled PP were tested to determine the optimal conditions for the injection moulding procedure. The effects of the processing parameters and the proportion of recycled plastic in composites on the mechanical properties were investigated, the optimal conditions for desired properties were obtained and then verified. The appropriate blending ratio of virgin and recycled plastic was evaluated. The results reveal that deteriorations in the mechanical properties of products produced from recycled plastic can be improved by optimizing the processing parameters during the injection moulding procedure.     

RTM成型工艺对复合材料制品性能的影响

RTM(树脂传递模塑的简称)成型工艺是一种将树脂注入闭合模具中浸润增强材料的复合材料成型工艺。工艺参数对复合材料制品性能有很大的影响。本文对注射压力、注射温度、真空辅助、注胶口和排气口的位置、纤维含量和结构等工艺参数对复合材料制品性能的影响进行了概述。     

新型鼠标底座注射成形流动仿真及模具设计

目的设计并制造出新颖、使用方便以及功能齐备的鼠标。方法采用3D打印技术打印了新型鼠标模型。在设计浇注系统的基础上,对新型鼠标底座的注射成形工艺流动过程进行了有限元仿真。分析了充填成形过程中的充填时间和冷却固化时间、体积收缩率与缩痕、塑件的变形情况、表层与心部的取向、残余应力以及气孔和熔接线等相关参数。结果成功完成了鼠标底座的注射成形模具的设计。结论采用3D打印技术与有限元模拟相结合的方法,来开发新型塑料制品,能有效节省设计时间、保证设计质量。     

Experimental investigations on the polypropylene behavior during ultrasonic welding

The polypropylene material meets the needs and requirements in automotive industry due to its features such as wide range of physical properties, ease of processing, and low cost. This research has focused on the investigation of the behavior of polypropylene during ultrasonic welding process. The lap welded samples were examined by modern methods such as Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), and Fourier Transform Infrared Spectroscopy (FTIR). Also, the morphology of the non-welded and welded regions of the polypropylene samples was analyzed by Scanning Electronic Microscopy (SEM) method. TGA and DSC results showed a negligible difference between the mass loss of the molded and the welded propylene materials. Furthermore, the SEM images revealed the formation of voids in close correlation with vibration amplitude. The weld strength and bond integrity appears to be higher for higher vibrations, emphasizing that the lap joint interface strength is higher when the tendency of voids formation is decreasing. The stress-strain curve of the material, plotted for three ultrasonic welding variants, illustrated that increasing the main process parameters (pressure, time, and vibration amplitude) makes the weld strength higher, but a decrease in plasticity was noticed in the welded polypropylene samples.     

动态注射成型聚丙烯制品的湿热老化性能研究

通过对动态注射成型聚丙烯制品进行人工加速老化,对其老化性能进行测试研究,探讨了聚丙烯制品的抗湿热老化机制.利用动态注射成型机注射成型聚丙烯制品,采用DSC等测试手段分析了稳态注射和动态注射成型的聚丙烯制品的性能特征,通过湿热老化试验(90℃,湿度为95%),对比分析了稳态注射和动态注射成型的聚丙烯制品老化期间力学性能的...     

The effects of moulding geometry on the structure and mechanical properties of fibre-reinforced polypropylene structural foam mouldings

The influence of weld lines and changes in moulding section thickness on structure and mechnanical properties has been determined for short glass-fibre reinforced polypropylene structural foam prepared using a short-shot moulding procedure at two different melt injection times. Results are discussed in terms of the variability in skin to core thickness ratio, moulding density and fibre orientation obtained in these mouldings and subsequent effects on flexural stiffness and impact energy to failure.     

粉末浸渍长玻璃纤维增强聚丙烯的压缩模塑

采用粉末浸渍的方法制备连续玻璃纤维增强聚丙烯预浸料,经切割获得长纤维增强聚丙烯粒子,采用单螺杆挤出机挤出形成模塑料,探索了模塑料的压缩模塑成型工艺,研究了成型后材料的力学性能及其影响因素。结果表明:粉末浸渍的长纤维增强聚丙烯经压缩模塑后可获得力学性能优良的制品;随着预浸料切割长度的增大、纤维含量的增加,材料的力学性能提高;在基体聚丙烯中添加接枝极性基团的功能化聚丙烯,可改善体系的界面结合,提高材料的力学性能,但功能化聚丙烯的含量超过一定值后,材料的冲击强度有所下降;适当提高模具温度、模塑料温度及成型压力,可以提高材料的力学性能。     

Study of the adhesion strength on overmoulded plastic materials using the essential work of interfacial fracture (EWIF) concept

The influence of the overmoulding processing conditions (melt and mould temperatures, holding pressure and injection rate) on the adhesion strength between two polymers in a hard–soft part was studied. The used materials were thermoplastic vulcanized elastomer (TPV) and polypropylene (PP). The study of the adhesion strength was made by measuring the essential work of interfacial fracture (EWIF) concept using a single edge-notched tension (SENT) geometry. It was observed that, the data distribution was good since an adequate correlation between the total work of interfacial fracture and the ligament length was obtained. It was verified that, when the melt temperature, and in some cases, the mould temperature are increased, a higher adhesion strength is obtained. These parameters affect in higher degree the adhesion strength, since they may improve the interdiffusion and the wetting process of the PP substrate by the molten material (TPV), causing as a result a good contact between them. A little influence was observed in the case of the holding pressure and injection rate.     

热塑性复合材料自动铺放工艺参数分析与优化

热塑性复合材料自动铺放原位成型（AFP）技术是高效低成本制造大型复合材料构件的关键,而自动铺放过程中工艺参数的选取及控制精度对成型构件的性能有较大影响,因此为保证原位成型后成型构件的性能,需分析自动铺放工艺参数对成型构件性能的影响并对其进行优化。本文基于热塑性复合材料自动铺放平台,以连续玻璃纤维增强聚丙烯（GF/PP）预浸纱为原料制备复合材料层合板,以层合板的力学性能为优化目标,根据响应曲面法原理设计试验,分析热气温度、热压辊压力及冷压辊压力各工艺参数及其耦合作用对层合板力学性能的影响,建立各工艺参数与层合板力学性能的二次多项式回归方程预测模型,通过预测值与实际值对比等检验分析,验证回归模型的有效性和可靠性,进而获得热塑性复合材料AFP最优工艺参数组合为热气温度为385℃、热压辊压力为0.3 MPa、冷压辊压力为1.1 MPa。     

工艺参数对短玻璃纤维增强PP复合材料注射压力和翘曲变形的影响

采用Moldflow对聚丙烯及其短玻璃纤维增强复合材料的注塑成型过程进行3D模拟分析,基于Taguchi试验设计方法(DOE),采用L16(45)正交矩阵进行试验设计,研究工艺参数对注射压力和翘曲变形的影响。结果表明,纤维含量对注射压力和翘曲变形影响作用较为显著,且存在最佳值;模具温度、熔体温度、保压时间和保压压力对注射压力的影响为单调的线性关系,但其对翘曲变形的影响较复杂。