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新型注塑螺杆性能研究 总被引:2,自引:0,他引:2
随着注塑技术的不断发展以及注塑物料种类的不断丰富,注塑螺杆的性能越来越引起人们的重视.通过自行开发的可视化实验装置和在线数据测控系统,研究了各种新型注塑螺杆的熔融、温度均匀性、塑化能力等性能,并和三段式通用螺杆进行比较.结果表明新型注塑螺杆的性能比普通三段式螺杆有较大的提高. 相似文献
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MADDOCK注塑螺杆性能研究 总被引:5,自引:1,他引:5
随着注塑技术的不断发展,注塑螺杆的性能越来越引起人们的重视。通过可视化实验和在线数据测控系统,研究了Maddock注塑螺杆的熔融、温度均匀性、塑化能力等性能,并和三段式通用螺杆进行比较。结果表明Maddock注塑螺杆的性能比普通三段式螺杆有较大的提高。 相似文献
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奥地利恩格尔公司(Engel Austria GmbH)近日推出一种新型双螺棱螺杆,可显著提高物料产量。该新型双螺棱螺杆具有如下特点:在加料段有高剪切力,确保被加工的物料在压缩之前就已经达到较高的熔融温度,从而防止"固体塞"的形成(这种"固体塞"会导致螺杆变形和磨损);副螺棱降低了入口区域中心的偏差,确保物料塑化时压力对称分布;物料在最初时是 相似文献
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动态成型注塑螺杆熔体输送能力的研究 总被引:1,自引:0,他引:1
根据动态注射成型时螺杆的工作特点,采用自行修正的Tanner本构方程研究了聚合物熔体在螺槽中的等温流动。同时,近似地给出了振动力场下注塑螺杆熔体输送能力的表达式,理论分析了振动参数对沿程压力降及动态成型熔体输送能力的影响。结果表明,振动力场使塑化过程中聚合物的粘度降低,流动阻力减小。沿螺槽方向的平均压力降减小,在保持成型条件不变的情况下,施加振动可以提高熔体输送能力。 相似文献
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首先建立注塑螺杆的模拟及优化平台,该平台以Injection Molding Plastification(IMP)软件为基础,结合DOE(实验设计)方法,将不同螺杆的模拟结果进行DOE分析和优化。重点对常规三段式螺杆的计量段结构进行了研究,分别采用模拟优化和实验优化的方法对计量段槽深和导程进行了优化。并将两种优化方法的优化结果进行对比,结果分析表明:模拟与实验优化结果比较接近,初步形成模拟与实验相结合的优化思路。在螺杆的模拟优化之前,对IMP软件的可靠性和准确性进行初步验证,通过比较模拟和实验获得的螺杆沿程压力、螺杆扭矩,结果表明该软件基本上能够较准确地反映实际加工过程。 相似文献
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从取向应力产生机理、熔体充模流动过程、流动与取向的关系着手,分析取向对注塑制品物理机械性能的影响。同时,指出各工艺参数对取向的影响程度。改善工艺条件或优化模具设计减小取向应力,使制品截面上的取向应力均匀化,对提高注塑制品质量有着重要意义。 相似文献
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北京化工大学和吉林石化公司研究院采用螺杆挤压脱水膨胀干燥一步法干燥稀土异戊橡胶,考察了机头温度、机筒温度、机头压力和螺杆转速对产品质量和生产能力的影响。确定了最佳工艺参数:螺杆转速为80~90r·min-1,机头温度为150℃,机筒温度为160℃,机头压力为14~16MPa。在最佳工艺条件下,装置运行和工艺参数控制平稳,干燥后稀土异戊橡胶挥发分含量小于1.0%,门尼黏度降幅小于10%,能够满足产品应用的要求。 相似文献
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Effect of screw design on hopper drawdown of spherical particles in a horizontal screw feeder 总被引:4,自引:0,他引:4
Screw feeders are used to remove material from hoppers and bins at a controlled rate. The evenness of the flow in the bin depends on the drawdown pattern, which in turn depends on the screw and hopper design, shape of the particles and wall friction effects. A key design requirement is to ensure that a progressive increase in the screws volumetric capacity is achieved along the entire length of the hopper's opening so as to produce even drawdown. If this is not achieved then compositional variations in the outgoing stream and other operational problems (such as caking) can be created. Screw designs to date have been generally based on analytical models and at times the predicted flow pattern is not achieved. In this study, the Discrete Element Method (DEM) is used to predict particle transport in a horizontal screw feeder system for a range of conventional screw designs including a variable screw pitch, variable screw flight outside diameters and variable core diameters. The influence of screw choice on the particle mass flow rate, the evenness of particle drawdown from the hopper, power consumption, screw wear and wall friction variations are all investigated. Important features captured by DEM that are not accounted for by the analytic model and which vary strongly between competing screw designs, include the particle circulation in the hopper, shearing of the particle bed in the trough just outside the screw and the spatially varying particle force along the hopper which leads to non-uniform drawdown and to the existence of large stagnant or slow moving zones. The screw design and consequent flow patterns also strongly affect the power draw with variations up to a factor of three and screw wear with large changes in their distribution and magnitude. Finally, the surface frictional properties of the screw are shown to strongly influence the rate of bed compaction within and along the screw leading to strong variation in mass flow rate, uniformity of drawdown and power draw. 相似文献
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结合制冷系统的特点,将制冷机的检修泄压管道引至-35℃制冷系统的吸气总管中,通过运行的-35℃制冷机回收检修泄压制冷机内的氨,不但解决了制冷机的泄压问题,而且具有泄压速度快、节约、安全、环保等优点。 相似文献
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在生产过程中,二效蒸发器换热管曾发生大面积堵塞的情况,经高压水清洗疏通后,才能维持生产。经检查发现,有一部分换热管发生了向下滑移的情况,有脱出管板的趋势,严重威胁生产的正常运行。分析了管子向下滑移的原因,并提出了处理的办法。 相似文献
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Until now, the pin-jointed net model has been a widely used method for the prediction of preforming shape for woven fabrics. However, it deals only with pure trellising (or shear) and neglects other possible deformation modes. In some cases, there is evidence showing that other deformation modes have relevance to, and effectiveness in forming the final shape. A model considering only the shear mode will not result in an adequate prediction. In this study, a slippage model is developed to modify the pin-jointed net model. Macrostructure of the fabrics is included in the slippage model in order to capture more deformation modes. Comparisons of experimental and simulation results are presented. It is shown that the numerical prediction using the slippage model has better agreement with experimental measurements. 相似文献
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