A theoretical melting model for a reciprocating-screw injection molding machine

A theoretical model for the transient melting behavior in a reciprocating-screw injection molding machine is proposed. The model is based on a steady state extrusion model, Neumann's melting problem, and a heuristic postulate for the transient behavior. The model predictions are compared to experimental melting data for low density polyethylene, acrylonitrile-butadiene-styrene polymers and polyvinyl chloride for a variety of operating conditions and two screw designs. A useful degree of correlation is demonstrated for all experimental cases.     

一步法注射成型机

简述了注射成型法与模压成型法相比所具有的诸多优点，同时指出了传统注射成型方法所存在的问题。着重介绍了一步法注射成型技术及其设备的结构特点、工作原理及工作特性。     

橡胶注压成型机

介绍了宁波千普公司设计开发的橡胶注压成型机的合模机构、注压机构、液压传动系统、电控系统.对橡胶注压成型机所需要做的进一步发展和提高进行了简要的分析.     

动态注射成型机塑化过程中的分散效应

采用电磁动态注射成型机塑化聚丙烯(PP)与纳米CaCO_3的共混料。通过扫描电子显微镜观察以及差示扫描量热法分析,探讨了振动参数对注射机预塑过程中分散效应的影响。实验发现,随着振动频率和振幅的增加,纳米CaCO_3在PP熔体中分散得更均匀,平均粒径逐渐减小;混合料的熔点向高温移动,混合质量得以改善,有利于完善结晶。因而表明,引入振动力场有效地促进了CaCO_3的分散,提高了注塑机的塑化效果。     

新型注射成型机

该文重点介绍了一种新型注射成型机,其创新之处在于可控制温度,能除去注射筒内的滞留胶。     

全液压内循环二板式注塑机

结合二板式注塑机的现有技术状况,全面深入地分析了新型全液压内循环二板式注塑机的结构与性能特点。新型二板式注塑机采用内循环式的合模油缸,省去液压油外部循环过程并简化液压系统结构,节能、节材效果显著。移模和锁模动作分别采用不同油缸,解决了力与速度的关系,锁模特性优异,成型性能稳定性高。机器配备伺服电机驱动定量泵的动力系统,节能降耗,噪音低。新型二板式全液压内循环注塑机将成为下一代注塑机的发展方向。     

橡胶注射成型机注射装置结构分析研究

主要介绍了橡胶注射成型机及其注射装置的发展情况,阐述了橡胶注射成型的特点以及注射装置设计要求,并对三种常用的注射装置的结构特点及应用作系统的分析比较.     

注塑机节能改造技术

<正>1原装的节能型注塑机型1.1全电动注塑机由五个伺服电机作原动力,分别驱动锁模、启模,调模、顶出,注射,熔胶、注射装置等机构工作,完     

Comparison of injection molding machine performance

A comprehensive study into the performance of 4 injection molding machines is reported, using identical mold, polymer, and processing conditions. Start‐up dynamics and process repeatability were directly compared across machine technologies. One servohydraulic, one proportional hydraulic and two servoelectric machines were used in the study, ranging in age from 14 years to 1 year old at the time of the study. Experiments were carried out at identical set molding conditions for a run of 400 parts and part quality and process parameters monitored. Results showed a significant start up period in each case, correlating strongly to mold temperature. Age of machine proved to be the most significant factor in determining process repeatability; modern machines having significantly lower variation than older ones. Differences between the operating characteristics of hydraulic and electric machines were detected, control of screw position in hydraulic machines being less repeatable, although this had a minor effect on part repeatability. Electric machines were found to use up to 4 times less energy than their hydraulic counterparts and operate more efficiently. POLYM. ENG. SCI., 45:857–865, 2005. © 2005 Society of Plastics Engineers     

浅谈注塑机的各种电热圈

本文主要介绍注塑机常用的电阻式电热圈、电磁感应加热圈、纳米红外电热圈的结构及工作原理,并对三种电热圈的特性进行分析。     

注塑机的价格性能分析及趋势预测

针对国内日趋激烈的注塑机市场竞争，本文主要采用科学的统计方法，对目前市场上现有的注塑机产品进行分析，找出与机器价格密切相关的机器性能参数。通过提取相关技术、财务数据，运用绘图分析的方法，充分论述了注塑机的价格与机器的合模力、注射容积、容模面积等参数都是成线性关系的。这些结论为业内企业今后如何开发新注塑机来满足客户的需要，提供了新的思路。     

An experimental study of plasticating in a reciprocating-screw injection molding machine

Experimental studies were performed with low density polyethylene, acrylonitrile-butadiene-styrene polymers and on polyvinyl chloride to elucidate the nature of the plasticating process in a reciprocating-screw injection molding machine. Melting data, obtained by use of the “cooling experiment,” and plastic temperature data reveal that the screw recharge process is a transient plasticating extrusion process which gradually approaches the equilibrium extrusion behavior as the screw rotates. If the screw rotation time is a high percentage of the total cycle time, the plasticating behavior is very similar to steady-state extrusion behavior, but if the screw rotation time is a small percentage of the total cycle time, the plasticating behavior is significantly different. Furthermore, better plasticating is obtained by use of a low RPM and high percentage rotation time than by a high RPM and low percentage rotation time.     

A physical model for a quality control concept in injection molding

In this work, a model is presented, which is the basis of a quality control concept for the injection molding process. Contrary to statistical methods, this model uses physical dependencies of two quality parameters on four influencing parameters. The influences of holding pressure, holding time, melt temperature, and mold temperature on part mass and dimensions are described based on the fundamental material behavior such as pvT‐data or energy equation. Furthermore, the influence of viscosity changes is indirectly taken into account using the injection work. Assuming only small deviations of the influencing parameters around an optimized operating point, the four parameters are treated as being independent from each other. With this assumption, a product ansatz was chosen with different functions for each influencing factor. Applying basic algebra, the starting equation was transformed into a form that describes either the change in part mass or characteristic part dimensions as a function of the influencing factors. The final equation for the part mass contains six model parameters, whereas nine model parameters are necessary for the equation for the part length. To obtain those model parameters some systematic experiments are required. Once the parameters are known, the model is able to calculate the change of the target values when the influencing factors vary around the operating point. The model was tested experimentally with focus on dimensions using a plastic cover made of an acrylonitrile butadiene styrene (ABS) grade. For the investigated part geometry and material grade, the process behavior was described well by the model. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

橡胶螺杆旋转注射成型技术及成型机的研究

对橡胶螺杆旋转注射成型技术及成型机进行了研究。通过对影响旋转注射压力、旋转注射能力和旋转注射温度有关因素的探讨,初步得出了橡胶螺杆注射成型技术及成型机旋转注射成型的基本规律。与传统橡胶注射成型技术和成型机相比,橡胶螺杆旋转注射成型技术和成型机具有塑化和注射同步进行、注射能力大、设备结构简单、生产效率高和产品质量好的特点。IIR密封套、轮胎胶囊和油田用螺旋泵定子氟橡胶泵衬的生产实践表明,本研制橡胶螺杆旋转注射成型技术和成型机的工艺是可行的,完全可以在橡胶制品,尤其是大型橡胶制品生产中应用。     

Adaptive model following control of the mold filling process in an injection molding machine

This paper is concerned with the practical application of the adaptive model following control (AMFC) theory on the cavity pressure control of the mold filling process in an injection molding machine. The experimental results indicate that the AMFC technique based on the modified Popov-Landau method is very useful for the cavity pressure control. Two kinds of control algorithms are implemented on a 16 bit microcomputer to control the cavity pressure. The results also show that the AMFC algorithm is superior to the classical PI control in this system when the acrylonitrile-butadiene-stryrene (ABS) is injected into a test specimen mold which is designed according to the ASTM code.     

注塑机电气控制系统的改造

介绍了注塑机电气控制系统的结构,具体说明了使用可编程控制器和触摸屏对注塑机传统电气控制系统进行改造的方法,分析了入机界面在该设备中的应用.     

洗衣机面板注射成型CAE分析

应用Moldfolw Plastics Insight(MPI)软件的流动、冷却、翘曲变形模块对洗衣机用聚丙烯面板进行注射成型数值模拟,并对注射成型工艺条件进行了优化.优化后的聚丙烯注射成型工艺参数:熔体温度为240℃,模具温度为70℃,注射压力为32 MPa,保压压力为26 MPa,注射时间为5s,保压时间为30 s...     

注塑机注射速度的模型预测控制及其仿真

注塑过程具有随机性、非线性以及时变性等特点,常规比例积分微分控制方法很难使注射速度控制达到理想的效果,为此提出了一种基于模型预测的注射速度控制方法。首先介绍了注塑机注塑工作原理,分析了注射速度控制系统,并通过模型预测算法得到当前采样时刻控制量以及下一时刻的控制量。仿真结果表明,基于模型预测的注射速度控制能够很好地跟踪快速变化的速度设定曲线,拥有较好的稳定性和抗干扰性。     

A comparison of short glass fiber reinforced polypropylene plates made by conventional injection molding and using shear controlled injection molding

This paper describes a comparison of the fiber orientation structures and resulting elastic properties of samples of short glass fiber filled polypropylene made by conventional injection molding and by the SCORIM (Shear Controlled Orientation in Injection Molding) process developed at The University of Brunel. The 3D fiber orientation distributions of the composites were measured using a unique transputer based image analysis system developed at The University of Leeds. The mechanical properties of the samples were characterized using an ultrasonic velocity technique, which allows a full set of elastic constants to be determined for each material. The link between fiber orientation distributions and measured elastic properties was then investigated using theoretical models developed in this laboratory.     

Effect of vibration parameters of electromagnetic dynamic plastics injection molding machine on mechanical properties of polypropylene samples

Dynamic injection processing experiments have been carried out on polypropylene using the self‐made electromagnetic dynamic plastics injection molding machine, and the effects of the vibration force field on mechanical properties of molding samples are studied, namely, the influence of vibration frequency and vibration amplitude on the mechanical properties of samples are researched by using tensile testing, impact testing, differential scanning calorimeter (DSC) and scanning electronic micrograph (SEM) techniques. The results show that the tensile strength and impact strength are both enhanced and the melting point shifts toward the higher temperature, which facilitates the perfection of crystal. The best vibration parameters for processing polypropylene using electromagnetic dynamic plastics injection molding machine are that frequency is from 3 to 9 Hz and amplitude is from 0.1 to 0.4 mm. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 972–976, 2006