共查询到18条相似文献,搜索用时 187 毫秒
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组合型腔浇注系统的模拟分析及优化设计 总被引:1,自引:0,他引:1
对于组合型腔的浇注系统,如果熔体不能同时到达各浇口并充满各个型腔,将导致压力分布不均匀,使制品的质量下降,浇口可能会出现凝固现象而导致后续过程的不能顺利进料,以至于出现充不满等问题。本文将注塑系统平衡的理论和数值模拟技术紧密结合起来,对浇注系统进行优化,得出了一组最佳的浇注系统方案,从而保证熔体能够基本上在同一时间充满型腔,实现熔体的平衡流动。从分析结果可知,要平衡熔体在组合型腔内的流动,分流道的截面形状和尺寸起到非常大的作用。 相似文献
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针对香皂盒套件注塑模组合型腔熔体流动不平衡的问题,利用Moldflow软件进行注塑数值模拟。从充填时间,速度/压力(V/P)切换点压力,注射位置处压力三方面对初始方案进行分析,确定浇注系统优化指标,采用流道平衡分析自动优化方案的流道尺寸进行优化设计。结果表明,优化后的浇注系统,型腔间的充填时间的不平衡率低于5 %,压力不平衡值小于5 MPa,注射位置处压力曲线能够平稳上升,有效改善了熔体流动不平衡。 相似文献
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组合型腔模具浇注系统的平衡优化设计 总被引:1,自引:0,他引:1
根据制品使用要求及原料的流动性能,采用了潜伏式浇口和侧浇口的组合浇注系统。利用Moldflow Plastics Insight软件,在填充分析的基础上,对浇注系统进行了优化设计,优化后的分流道及浇口尺寸可保证组合型腔的平衡填充及型腔压力的均匀分布。 相似文献
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高汉华 《现代塑料加工应用》2012,24(6)
借助Moldflow 6.1软件的填充分析模块和流道平衡模块,分析组合型腔模具的不平衡流动.结果表明:同时调整型腔布局和优化流道截面尺寸,流动不平衡率可从4.19%下降到0.47%;当熔体流动不平衡率较大时,应首先考虑调整型腔布局,再结合调整流道截面尺寸、浇口等因素使之达到流动平衡;型腔布局对熔体的平衡流动起着重要作用. 相似文献
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注塑模充填过程动态模拟 总被引:7,自引:0,他引:7
本文基于注塑模型腔内充填机理和流体力学基本方程,视聚合物熔体在型腔中的流动为平行板中的流动,在浇注系统中的流动为等效圆柱管内的流动,在此假定的基础上进行合理简化,建立了三维薄壁型腔的基于非弹性、非牛顿流体在非等温下的Hele-Shaw流动的数学模型及浇注系统的数学模型,并采用混合有限元/有限差分数值方法耦合求解压力方程和能量方程,采用控制体积法自动跟踪熔体前峰面,从而实现充填过程的动态模拟。模拟结 相似文献
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将模具计算机辅助工程(CAE)技术引入汽车内饰件组合型腔注塑模的设计。根据流动过程的模拟分析,改善模具浇注系统的结构尺寸,流动不平衡率从7 %降为1.4 %,利用气穴分析和冷却分析优化了排气系统和冷却系统的设计,提高了模具的设计质量,为组合型腔模具的优化设计提供了参考依据。 相似文献
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水辅助熔体充模流动的熔体流痕 总被引:1,自引:1,他引:0
构建了用于研究水辅助熔体充模的仿真模具,采用红色和绿色着色剂作为示踪剂,通过水辅助着色的聚丙烯(PP)熔体在柱状模腔里充模,获得了能够反映熔体流动痕迹的样品。通过观察流痕,对水作用下熔体的充模流动进行了研究。实验结果表明:在一次穿透中,与注水喷嘴接触的高黏度熔体造成水从喷嘴射入熔体的不稳定,水的穿透导致模壁附近熔体可能产生回流现象,回流沿水的穿透方向呈减弱趋势。在二次穿透中,水前缘熔体黏度和黏度分布对水的穿透影响较大,熔体体积的收缩是近似线性的减小过程,熔体的剪切流动弱于一次穿透。实验中还发现,水前缘的熔体也会产生"喷泉流"。 相似文献
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Numerical and experimental investigations on polymer melt flow phenomenon in a vario‐thermal mold cavity 下载免费PDF全文
Mold temperature is one of the key factors affecting the morphology and quality of plastic parts. This article explores the melt flow phenomena in a vario‐thermal mold cavity. A coupled numerical method, considering the conjugate heat transfer between the mold and melt, is developed for the melt flow simulation. Mold temperature variations and melt flow phenomena for short shot injection in an electrical heated mold cavity are numerically studied and verified by experiments. The results indicate that the melt flow length and cavity filling ratio increase significantly with the elongation of the preheating time before injection. Melt filling ratio increased nearly linearly with the increasing of electric heating time. The smaller the injection pressure is, the bigger the relative filling ratio increment is. Therefore, polymer melt can flow much longer or the mold cavity can be filled up with a smaller injection pressure when the cavity is preheated. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45193. 相似文献
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以手机前盖及前饰板两个非等体件共模结构为分析实例,阐述在不同体积型腔的模具流道设计中,利用MPI软件对不同流道的设计进行对比分析。主要对比分析了三种典型的浇注方式对浇注时间、转换压力及锁模力三个要素的影响,再根据产品的需求选择合适的流道设计,最后利用分析出的两腔填充时间比值确定产品流道截面的尺寸。优化了分流道,使塑件的填充达到了流动平衡,尽可能减小了塑件的缺陷。 相似文献
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Cavity pressure has been recognized as a critical process parameter for the injection molding of high quality thermoplastic parts. This Interest has led to the achievement of closed loop cavity pressure control, but only at one point in the mold cavity. A system has been recently described that extends this capability to provide simultaneous control of cavity pressure at multiple locations in the mold through the addition of dynamic valves in the melt delivery system, each of which can be independently controlled to meter flow and pressure to its portion of the mold. This paper describes the ability of the multi-cavity pressure control system to improve process capability and molded part quality. Experimental investigation has shown that the technology enables significant process flexibility to arbitrarily balance flow, move knit-lines, and control multiple part dimensions. In the presence of typical production process disturbances, moreover, closed loop multi-cavity pressure control was shown to increase the process capability index, Cp, from 0.52 for the conventional injection molding process to 1.5. After these capabilities have been discussed, several limitations of the process are described that lead to promising areas of future research. 相似文献
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For microinjection molding, it is envisaged that cavity surface roughness plays an important role in the cavity filling of polymer melt. This article presents an experimental investigation into the surface roughness effects on the flow area of a microthickness disk through injection molding. Three core inserts, each of which has different surface roughness on its two semicircular halves but with the same roughness mean lines, were machined and formed the mold cavity. The difference in flow area (or volume) between these two semicircular halves of the molded part was investigated by varying the mold and melt temperatures. Regressive analysis of the significance of mold and melt temperatures and cavity thickness on the surface roughness effects was carried out. Experimental results obtained indicated that the flow area on the smoother half is larger than that on the rougher half during cavity filling. For the same surface roughness, its effect on cavity filling is a function of mold temperature, melt temperature, and cavity thickness. An increase in mold temperature or melt temperature will result in smaller surface roughness effect on the flow area. When cavity thickness is reduced, the surface roughness effect will become more significant. Moreover, a larger difference in the surface roughness between the two semicircular halves of the insert will result in a larger difference in the flow area between the two halves of the molded part. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers. 相似文献
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采用Level Set两相流方法模拟了熔体充模过程,避免了处理复杂的边界以及用Ghost方法将熔体内的速度值外推到熔体外的情况。分别对型腔水平中面与垂直中面的充模过程进行了模拟。讨论了不同注射速度、不同注射口数量以及不同Reynolds数对充模过程的影响,得出了不同时刻各种情况下熔体界面的位置与充模过程刚结束时型腔内的压力分布,分析了熔体在型腔内运动的不同阶段的特点及形成不同阶段的原因。结果表明,在注射口宽度与型腔宽度相差不大的情况下,如果采用中低速充模,则整个充模运动过程以比较平稳的扩展性运动为主,充模较完全,熔体不发生破裂,制件效果较好。充模速度越大,熔体达到平稳流动的时间越短,充模过程越短。数值模拟结果与实验结果一致,同时表明Level Set两相流方法在求解拓扑性质发生较大变化问题时具有很大的优势。 相似文献