专利文摘

汽车玻璃钢化加热炉用的成型模 汽车玻璃钢化加热炉用的成型模，它包括一个成型模腔体，其特征在于：所述成型模腔体通过螺栓连接在成形模腔体安装板上，成形模腔体安装板通过螺栓连接在成形模框架上；所述成型模腔体与上部真空发生器连接口连通，所述成型模腔体在其工作表面上有均匀分布的多个吸气孔，     

陶瓷凝胶注模成型技术及其应用研究

凝胶注模成型技术是一种近净尺寸陶瓷成型技术，它为解决陶瓷材料的加工成型问题提供了一条十分有效的工艺途径。介绍了陶瓷凝胶注模成型技术的基本原理和工艺过程，着重介绍了目前凝胶注模成型技术的应用研究。     

陶瓷凝胶注模成型技术及其应用研究

凝胶注模成型技术是一种近净尺寸陶瓷成型技术,它为解决陶瓷材料的加工成型问题提供了一条十分有效的的工艺途径。介绍了陶瓷凝胶注模成型技术的基本原理和工艺过程,着重介绍了目前凝胶注模成型技术的应用研究。     

波纹管成型凸模半径优化设计

成型凸模半径对波纹管下井后的膨胀性能有重要影响。针对成型凸模不同半径尺寸对波纹管成型过程中力学特性的影响,基于金属弹塑性力学、板材成型理论及有限单元法,建立了波纹管成型过程及力学行为的有限元模型,并利用有限元软件ABAQUS对该模型进行了仿真计算,从而得到了成型后的波纹管形状,并获得了成型凸模半径对成型过程残余应力和残余应变的影响,进一步求取了成型凸模半径的最优值为25mm。     

凝胶注模成型工艺的研究进展

系统地介绍了凝胶注模成型工艺十余年来的研究进展 ,重点介绍了HMAM工艺和TRG(热可逆转变凝胶注模成型 )两种新型工艺 ,并列举了凝胶注模成型工艺在金属和无机非金属材料方面的应用。最后提出了凝胶注模成型工艺需注意和解决的问题 ,并展望了其未来发展前景。     

玻璃钢抽油杆挤拉成型设备研究

本文论述了玻璃钢抽油杆挤拉成型设备中送纱装置、分纱器、浸胶装置、预成型模、成型模、烘道、牵引装置的结构特点和设计要求,针对6.35mm、25.4mm玻璃钢抽油杆的生产,给出了玻璃钢抽油杆挤拉成型生产流程图和浸胶槽、分纱板、分纱器压板、预成型模、成型模的图示,讨论了各单元设备在玻璃钢抽油杆挤拉成型中的作用。试验结果表明分纱板、预成型模、成型模的设计在整个成型中比较重要。成型模的入口处必须车削成一个7～10°的喇叭口,这样可使纱线在模内被压紧,使产品密实性好,避免“飞纱”现象发生,使产品连续生产。     

圆环和锥形口模挤出吹塑的数值研究

用Polyflow软件的Carreau本构模型,数值模拟了用于管材挤出吹塑和型坯成型的圆环口模和锥形口模内熔体及其型坯的三维等温流场,考虑了挤出胀大和垂伸效应的综合影响,分析了两种口模的差异.数值计算结果表明,对于同一直径和口模间隙的环形口模和锥形口模,在相同入口流量下,环形口模内熔体的压力梯度大于锥形口模,环形口模成型型坯的厚度小于锥形口模,环形口模成型型坯的直径大于锥形口模;环形和锥形口模内熔体的压力梯度随着入口流量的增加而增加,在环形和锥形口模成型型坯的底端,型坯的厚度和外半径随着入口流量的增加而增加;锥形口模成型型坯厚度较环形口模对流量更敏感.     

薄壁注塑成型中的变模温控制技术

介绍了薄壁注塑成型中存在的主要问题,阐述了变模温控制技术在薄壁注塑成型中的重要性,综述了当前各种变模温控制技术的原理及其在薄壁注塑成型中的研究与应用进展,并展望了未来薄壁注塑成型中变模温控制技术的发展趋势。     

自润滑液膜辅助模内微装配成型精密控形技术与机理研究

针对模内微装配成型过程中,预成型微型件的热流固耦合变形难以精确控制的技术难题,研究提出了高速自润滑功能液膜辅助模内微装配成型精密控形创新工艺。结果表明,高速自润滑功能液膜辅助模内微装配成型能使预成型微型件的黏弹性热流固耦合变形精密控制在几十微米的精度内,实现了聚合物微细机械系统的模内微装配成型高精度微装配加工;通过高速自润滑功能液膜辅助模内微装配成型与传统模内微装配成型对比分析研究,揭示了高速自润滑功能液膜辅助模内微装配成型创新工艺精密控形的机理。     

汽车功能键触摸盖IMD高压成型工艺与模具设计

针对汽车内饰功能件模内装饰(IMD)成型的需要,设计了该功能件的IMD成型工艺方案,完成了两副关键设备的结构设计.IMD成型工艺包含膜片文创图案丝印、膜片预成型、膜片冲裁、膜片模内注塑等环节.针对膜片预成型工序设计了一种膜片高压预成型模具;针对模内注射成型工序,设计了一种两板两腔单次分型侧浇口注塑模具.实践证明,该成型...     

聚合物熔体在不同挤出口模内流动的数值模拟研究

构建了3种构型的圆棒挤出口模，采用有限元分析软件POLYFLOW对聚合物熔体在挤出口模中的二维等温流动进行了数值模拟，分析了熔体在不同口模内的速度和压力分布。结果表明，直线形口模在入口处易产生局部环流，而喇叭形和流线形口模可有效消除局部二次流动。在相同条件下，喇叭形口模在出口处存在较大的挤出负压，为-172．9MPa，而流线形口模为-43．72MPa，两者相比，后者压力降低了75％。因此流线形口模在3种几何构型中结构最为合理。     

多腔精密医用导管机头结构及口模设计研究

介绍了较佳的多腔精密医用导管机头结构,并对两类典型多腔精密医用导管的机头定型段流场进行了数值模拟分析,获得了出口截面上的速度分布图。同时研究了截面上沿最大壁厚路径及最小壁厚路径上的速度分布,提出了整个截面速度均匀性的定义。此外,综合实际挤出过程中注气这一特征,给出了修正后的口模截面形状,同时进行了定型段流场的模拟。结果表明:修正后口模截面的速度均匀性和壁厚均匀性都有了很大的提高,这对同类机头的结构设计及口模截面的确定具有较强的参考价值。     

A parallel coextrusion technique for simultaneous measurements of radial die swell and velocity profiles of a polymer melt in a capillary rheometer

This article proposes a new experimental technique to simultaneously measure radial die swell and velocity profiles of polystyrene melt flowing in the capillary die of a constant shear rate rheometer. The proposed technique was based on parallel coextrusion of colored melt‐layers into uncolored melt‐stream from the barrel into and out of the capillary die. The size (thickness) ratio of the generated melt layers flowing in and out of the die was monitored to produce the extrudate swell ratio for any given radial position across the die diameter. The radial velocity profiles of the melt were measured by introducing relatively light and small particles into the melt layers, and the times taken for the particles to travel for a given distance were measured. The proposed experimental technique was found to be both very simple and useful for the simultaneous and accurate measurement of radial die swell and velocity profiles of highly viscous fluids in an extrusion process. The variations in radial die swell profiles were explained in terms of changes in melt velocity, shear rate, and residence time at radial positions across the die. The radial die swell and velocity profiles for PS melt determined experimentally in this work were accurate to 92.2% and 90.8%, respectively. The overall die swell ratio of the melt ranged from 1.25 to 1.38. The overall die swell ratio was found to increase with increasing piston speed (shear rate). The radial extrudate swell profiles could not be reasoned by the shear rate change, but were closely linked with the development of the velocity profiles of the melt in the die. The die swell ratio was high at the center (～1.9) and low (～0.9) near the die wall. The die swell ratio at the center of the die reduced slightly as the piston speed was increased. Polym. Eng. Sci. 44:1960–1969, 2004. © 2004 Society of Plastics Engineers.     

C形口模共挤出胀大的三维黏弹数值研究

运用有限元方法,采用PTT本构方程和Arrhenius黏度对温度依赖方程,对C形共挤口模中的聚丙烯(PP)和聚苯乙烯(PS)两熔体进行了三维非等温黏弹数值研究,主要研究了口模入口端熔体层间界面位置（r）对挤出胀大率和界面位置稳定性的影响,研究表明,随着r的增大,口模出口处熔体的二次流动程度减弱,挤出胀大率减小;在两熔体入口流率相等的情况下,取使得两熔体入口面面积近似相等的r值,能保证口模内及口模出口端熔体层间界面位置稳定性较好。     

Effect of die design on die drool phenomenon for metallocene based LLDPE: Theoretical and experimental investigation

The effect of die design on the die drool phenomenon was investigated for metallocene based LLDPE. It has been found that die exit opening and the flared die design can significantly reduce the die drool phenomenon. Moreover, theoretical research has revealed that die drool onset can be explained by the negative/nonmonotonic pressure profile generated inside the die and/or at the die exit region. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Die geometrical effect on annular die swelling

Die geometrical effect on Newtonian annular jet swelling was studied using a finite element method. Numerical result shows what we expected in the limiting cases of die swelling with annular die geometries, i.e., variation of the die gap for straight dies follows the limiting behavior of capillary and planar die swellings. Also the effect of upstream die geometry was investigated. The result shows that final extrudate dimensions are generally influenced by its previous history in the die, i.e., not only by shearing action but also by elongational effect caused by narrowing die gap.     

硬质聚氯乙烯低发泡管材的单螺杆挤出成型

采用单螺杆挤出机进行了硬质聚氯乙烯低发泡管材挤出成型，研究了树脂牌号、预塑化对管材性能和泡孔结构的影响，探讨了口模与定型模的匹配问题，对比了普通口模与专用口模的差异及其对管材外观及性能的影响。结果表明，采用经预塑化的PVCS－1000树脂生产的管材具有优良的外观和理想的泡孔结构。专用发泡口模与普通口模相比，在压缩比相同的前提下，平行段长度由110mm缩短为50mm。     

轮胎胎面翼胶挤出破边问题改善方法的研究

分析轮胎胎面翼胶在挤出过程中的破边问题,发现口型开型比设计、口型进胶口倒角设计和口型温度均为影响因素。通过减小口型开型比、增大口型进胶口倒角高度和深度及口型设定温度,胎面翼胶挤出破边问题得到有效改善。     

Rheological properties,flow visualization and extrudate swell of NR compound by rotating‐die rheometer

An experimental apparatus coupled with a rotating die system was especially designed and manufactured to study the rheological properties, flow patterns and swelling behavior of natural rubber (NR) compound for different shear rates and die rotating speeds at a test temperature of 110°C, the results being compared with those by the static capillary die. It was found that NR compound used exhibited psuedoplastic non‐Newtonian behavior. The rotation of the capillary die could reduce the extrusion load. The wall shear stress for any given shear rates increased with increasing die rotating speed. The fluctuation of the entrance pressure drop increased with increasing die rotating speed. The flow pattern development in the rotating‐die rheometer was different from that observed in the static die. The flow patterns in the rotating die were clearly unstable and contained two flow components which included axial flow along the barrel and circumferential flow at the die entrance. The size and shape of the axial and circumferential flows were more dependent on the piston displacement. It was found that the swelling ratio of the NR compound decreased with increasing die rotating speed. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers.     

Structure evolution and orientation mechanism of isotactic polypropylene during the two‐stage solid die drawing process

High oriented isotactic polypropylene prepared by self‐designed two‐stage die drawing apparatus was explored through kinds of methods, including differential scanning calorimetry, two‐dimensional wide‐angle X‐ray diffraction, polarized light microscope, and tensile test. The results showed that there was a great difference between the orientation mechanism and structure evolution of two‐stage solid die drawing process and single‐stage solid die drawing process. All samples would undergo free drawing process after die drawing process. Die drawing and free drawing process were of equal importance to single‐stage die drawing process while die drawing process showed an prominent contribution to the two‐stage die drawing process. Drawing speed showed beneficial influence on die drawing process for both single‐ and two‐stage die drawing process routes. Under the same processing condition, tensile strength and modulus of samples prepared by two‐stage die drawing process were higher than those prepared by single‐stage die drawing process and the maximum value could reach 241.93 MPa and 3.57 GPa, respectively. Moreover, two‐stage die drawing samples showed better dimensional stability than single‐stage die drawing samples especially under low draw rate. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46581.