Amplitude–frequency characteristics of polymer electro‐magnetic dynamic tri‐screw extrusion

The mechanism of plastic forming and processing in electromagnetic dynamic tri‐screw extruder is very sophisticated and the investigation of amplitude–frequency characteristic acts as the foundation of equipment design and the optimization of polymer processing parameters. A mathematical and analytical model of plastic forming in such extruder was developed and the results were nondimensional‐normalized. To validate the mathematical solutions experiments based on LDPE were carried out and the experimental vibration amplitude and vibration frequency curve was obtained. Three conclusions can be drawn herein: (1) the experimental results hold a good agreement with the calculations, and thus the feasibility of the proposed model is validated; (2) the possibility of resonance closely relates to polymer melt viscosity, rotating speed, and geometry parameters of the screw; (3) resonance of the tri‐screw extruder is seldom observed under normal conditions and there exists an inverse correlationship between vibration frequency and amplitude. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci 122:1778–1784, 2011     

Evolution of Chemistry,Morphology and Rheology of Various Polymer Systems along a Twin‐Screw Extruder

Intermeshing twin‐screw extruders have been recently identified as useful in special application niches such as the extrusion of PVC dry blends (counter‐rotating machines) and compounding operations (co‐rotating machines). Thus, it is of interest to study the mechanical and/or chemical effects that occur along the screw axis of the extruders, since they will dictate the characteristics and performance of the final material. This work aims at illustrating the usefulness of a simple experimental tool recently developed for the study of the physical, chemical and morphological evolution along the extruder of polymer based systems, data being presented and discussed for a number of composites and blends.     

实验室RIM机的开发

介绍本所试制的一台实验室用反应注射成型机（RIM0）的主要结构、性能。     

啮合同向双螺杆挤出过程新型混合元件—六棱柱元件实验研究

前文^[1]对啮合同向双螺杆挤出过程中的新型混合元件－六棱柱元件的流场了三维等温牛顿模拟，并将其结果与捏合块元件作了对比，得到了在相同压差下六棱柱元件比捏合块元件产率高，剪切速率场和剪切应力场分布更均匀，且两种元件分散混合能力相近的结论。本文对六棱柱元件的流场模拟结果进行了实验验证，证明流场模拟计算的方法可行，得到的结果可靠。进而利用多种有效方法，对六棱柱元件的挤出，混合特性进行了实验研究、实验结果表明，六棱柱元件比捏合块元件比能耗小，出料温度低，分布混合能力强，且六棱柱元件适于玻璃纤维增强改性加工过程。     

啮合同向双螺杆挤出过程非啮合开槽螺纹元件组合流道三维流场分析

应用ANSYS有限元分析软件对啮合同向双螺杆挤出过程包括非啮合多过程螺纹元件（NI-MPE）组合流道进行了等温非牛顿三维流场模拟分析，得到了包括NI-MPE元件的组合流道的压力场、速度场、剪切速率场和剪切应力场，并与包括非啮合常规螺纹元件的组合流道的模拟结果进行了对比。     

螺杆挤压机混合能力的分析

分析螺槽中熔体的流动状态 ,运用加权平均总应变来评价螺杆挤压机的混合能力 ,进而提出提高混合能力的途径。对于单螺纹螺杆 ,稍长的计量段 ,稍浅的计量段螺槽及较高的螺杆转速 ,有利于混合作用 ;开发新型螺杆 ,如犁钉分流混合螺杆 ;研制高效混合型螺杆挤压机 ,如球窝型高效混合型螺杆挤压机     

螺杆空压机增卸载状态下故障的分析及处理

文章以两级压缩螺杆空压机为例,叙述和分析了机组分别在增卸载不同运行工况下,因内部工艺运行和部件工作状态发生改变,导致润滑油循环系统、空气系统出现变化所引起排气高温报警故障的现象和原因,并对此提出了故障消除的方法。     

旋风铣削圆锥螺纹的误差分析

旋风铣削圆锥螺纹具有工装简单，效率高的特点，但只能用于粗加工，就此从理论上分析误差产生的原因，并探讨了误差螺纹精度的影响，从结构提出了一些改进措施。     

系列变螺距螺杆的设计计算

为了使罐头包装机具有柔性加工的功能并提高设备利用率,根据圆柱形罐的螺杆供送机构的原理,设计开发了可调变螺距螺杆供送机构和对应不同罐径的系列变螺距螺杆。根据对罐的运动规律要求,给出了变螺距螺杆结构参数的设计计算方法以及罐的运动规律的计算分析方法。阐明了罐运动规律与螺杆长度、罐直径、螺距、螺距数之间的关系。研究的变螺距螺杆的设计计算及运动规律分析方法适合常用的罐径系列。     

高速分件供送变螺距螺杆螺旋线组合形式的研究

本文分析瓶罐高速供送变螺距螺杆设计与应用存在的问题，在螺杆螺旋线三段式基础上，提出了四段式的组合形式，即等速段、正弦变加速段、等加速段和正弦变减速段。