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塑料异型材挤出模头稳定性设计的数值方法 总被引:1,自引:0,他引:1
根据挤出模头设计的最小横向流动理论,运用ANSYS有限元分析软件,模拟分析了两副模头分流段流道的三维非牛顿流场,讨论了分流段流道设计对模头稳定挤出的影响;指出分流段流道设计满足流动平衡条件时,流道横向流动最小,模头的稳定性能较好;并通过两副实际使用的挤出模具,验证了理论分析与实际的一致性,从而给出了塑料异型材挤出模头稳定性设计的数值方法。 相似文献
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本文详细分析了有关异型材挤出口模的设计,提出了成型段设计的理论依据,并认为在品模设计过程中,设定不同流道中霜一对应段的压降相等,其理论依据是熔体的平均剪就国相同或平均体积粘性耗散能相同,进一步完善了口模的设计方法。 相似文献
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利用Flow 2000软件,从3个方面对塑料异型材挤出模头中功能块成型结构的设计进行了分析,即进行部分功能块的结构改进、流道中功能块局部流速过慢的处理、流道中功能块局部流速过快的处理。从而确保成型区上功能块的流道截面图形设计及平直段长度的设计满足挤出模头流道设计的基本要求,提高了挤出模具的设计水平,缩小了与国外设计上的差距。 相似文献
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PVC profile extrusion compounds have a unique morphology. While other polymers gradually decrease in extrusion die swell with increasing length/thickness (L/D) ratio, PVC profile extrusion compounds have a low die swell, quite independent of the die's L/D ratio in the range of 5 to 20. The fact that the die land length can be changed without changing the extrudate swell is an important consideration, which makes die design and balancing dies simpler and easier for PVC profile extrusion compounds. While other polymers substantially increase extrudate swell with increased shear rate, the swell of the PVC profile compounds is not much affected by shear or extrusion rate. This unique behavior allows wider processing latitude in profile extrusion and faster extrusion rates than with other polymers. Another unique factor in the rheology of PVC profile extrusion compounds is that extrusion die swell increases with increasing melt temperature, while other polymers have decreasing die swell with increasing melt temperature. The unusual rheology of PVC profile extrusion compounds is attributed to its unique melt morphology, where the melt flow units are 1 um bundles and molecules that have low surface to surface interaction and entanglement at low processing temperatures but increased melting and increased entanglement at higher processing temperatures. Other polymers, unlike PVC, have melt flow at the molecular level. 相似文献
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塑料熔体在挤出模中的流动状态分析是挤出模设计的基础。尽管塑料异型材的成型模具种类繁多、形状各异,但都可视为圆环和孔隙的组合。分析了模头流道结构和熔体在圆环型材挤出模中的流量,为环类型材挤出模设计提供了依据。 相似文献
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This paper describes the results of a study of the effect of extrusion conditions on the gloss of rigid PVC profiles. Extrusion variables investigated are extrusion melt temperature, extruder temperature settings, extrusion rate, and the die/sizer metal surface condition. It is hoped that this information will help PVC profile manufacturers to optimize their process for achieving desirable gloss. 相似文献
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针对聚合物双腔微管直角挤出模具非对称流道结构,基于聚合物流动平衡原理,建立了直角挤出模具非对称流道结构参数关系。在直角挤出模具的挤出成型方向上,采用反向流道的方法计算流道长度,并对反向流道的终点进行拟合,基于拟合偏差构建了目标函数,对模具非对称流道结构进行了优化设计。根据优化结果设计制造了双腔微管直角挤出模具,并且进行了挤出成型实验。实验结果表明挤出模具非对称流道设计是合理的,证明了聚合物双腔微管直角挤出模具非对称流动平衡设计方法的正确性和有效性。 相似文献
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以典型的美式截面型材为例,从塑料异型材组装、使用及成型的角度,对挤出模具口模部分的各段流道进行了分析,对定型模中水气路排布、尺寸放量与口模的匹配程度、物料特别是对内筋在定型模中冷却定型规律进行了总结,对定型水箱中定型块等作用进行了分析,探讨了如何完善塑料异型材模具的设计问题。 相似文献
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PVC卷帘窗型材挤出机头的设计 总被引:2,自引:0,他引:2
对聚氯乙(烯PVC)卷帘窗型材结构进行了工艺分析,并介绍了该型材挤出机头的设计要点,重点阐述了机头的结构组、成及其设计思路。实践证明该,机头结构合理操、作简单能,生产出符合尺寸要求的PVC卷帘窗型材。 相似文献
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塑料异型材挤出口模的三维罚有限元设计 总被引:1,自引:2,他引:1
讨论了现有塑料异型材挤出口模研究中的流变学分析方法,指出了前人运用流变学方法设计挤出口模的不足。本文采用三维罚有限元方法,对幂律流体在塑料异型材口模中的流动进行了计算机模拟研究,阐述了采用三维罚有限元方法进行塑料异型材挤出口模设计的重要意义 相似文献
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R. S. Lenk 《应用聚合物科学杂志》1978,22(7):1775-1779
A simple method is presented for calculating the pressure drop for the flow of power law liquids in dies with a wide slit profile and with vertical and/or lateral tapers, as well as in dies with the shape of a circular truncated right cone. Tapered dies are known to give improved extrudate quality and/or higher output rates without encountering extrudate defects which occur in dies with parallel channels at similar extrusion pressures. A possible ultimate optimization of the extrusion process—as far as die design is concerned—is discussed. It is suggested that this be based upon an extension of the method from dies with a rectilinear convergent taper to dies with a curvilinearly converging channel aspect the generation of which latter is indicated. 相似文献