注塑机节能中变量泵与变频技术的应用现状

注塑机节能是目前研究的一大热点,在动力驱动系统节能方面,主要有两种节能方式:即采用比例变量泵进行节能与变频器驱动定量泵节能,对这两种主要节能方式的特点进行了详细介绍,并论述了注塑机节能技术的发展趋向.     

普传变频器在注塑机节能改造中的应用

目前，在我国的注塑生产厂家中，仍有相当数量的传统非节能型注塑机在运行着。这不仅不符合我国的节能降耗政策，而且大大增加了生产商的用电成本。而采用变频器对现有注塑机进行节能改造不失为解决这一问题的很好途径。     

普传变频器在注塑机上的应用

注塑机是对各种塑料进行加热、融熔、搅拌、增压后,将塑料流体注入模具控内,完成工件一次注塑成型的设备。它的工序过程基本是相同的,每一个工序都需要不同的压力和流量,也就是说被加工的工件不都是在最大压力或流量下工作的,传统方式其压力和流量是靠压力比例阀和流量比例阀来调节的。而油泵电机在恒速运转,造成能量的浪费。若用变频器来调节电机(油泵)的转速,实时满足压力和流量的需求,这样既经济又实用。有关单位已成功地使用我公司普传变频器控制柜改造了的注塑机,取得了显著的经济效益,因此用变频器改造注塑机节能是值得向广大用户推广的。根据实际经验,属中、小型注塑机用变频器改造后的节电率一般在20%～60%。     

电磁感应技术在注塑机节能改造中的应用

介绍了电磁感应加热系统的工作原理,以某注塑机为实例,采用电磁感应技术对其加热系统进行了改造.结果表明,对注塑机进行电磁感应加热改造的成本低,注塑机预热时间由改造前的30 min缩短为改造后的20 min,综合节电可达50％,节能效果显著.     

注塑机变频节能技术的应用

随着塑料加工行业的高速发展和竞争加剧，对注塑机进行节能改造以降低生产成本的呼声越来越高。本文阐述了采用变频调速技术对注塑机进行节能改造的原理特点及相关产品概况，分析了现场应用中可能出现的技术问题及相应对策，并通过实例介绍了节能空间和投资回收期。     

厦门启动千家万台注塑机节能改造

<正>近日,厦门市注塑工业协会表示厦门市千家万台注塑机伺服节能改造控制系统试点已启动,由此拉开福建省内注塑机节能改造的序幕。厦门是继广东东莞和湖北武汉之后,国内第三个启动千台注塑机节能改造工程的城市。厦门市注塑工业协会会长说,通过引入伺服节能改造技术,注塑机最高可实现40%~50%的节电效果,满负荷生产情况下一年左右就可收回改造成本,而且还具有提高设备生产精度,降低生产噪音,减少液压油的老化消耗等附加效益。     

变频技术和变量泵在注塑机节能方面的应用研究

介绍了变频液压技术和比例变量泵技术两种注塑机节能方式的特点和应用情况,并论述了注塑机节能技术的发展趋向.     

变频器技术在注塑机上的应用

利用变频器技术对注塑机进行改造，通过对液压系统输出流量和压力的控制，使液压泵的工作转数随着注塑机工作状况的变化而相应地改变，从而达到对液压系统的工作流量和工作压力进行实时控制的目的，避免了能量浪费,降低了生产成本。     

注塑机节能控制技术的最新发展与应用

介绍注塑机开发设计中应用较多的比例变量泵系统、变频液压控制系统和全电动注塑机等几种节能控制技术及它们的结构原理和应用,分析对比了相关节能控制技术的最新特点,并讨论了注塑机节能控制系统的最新发展方向。     

基于AMESim的注塑机合模机构的能耗分析

节能是注塑机发展的一个重要方向。文章对3种注塑机的液压系统:定量泵+比例压力流量阀系统、比例变量泵系统、定量泵+伺服电机系统各自的特点进行了介绍,并以合模力为1 000 k N的二板直压式注塑机为研究对象,基于液压仿真软件AMESim搭建了3种液压系统的仿真模型,分析了3种不同液压系统在注塑机开、合模及顶出阶段的功率和能耗。仿真结果表明,完成同样的开合模动作,定量泵+比例压力流量阀系统能耗最高;与定量泵+比例压力流量阀系统相比,比例变量泵系统节能47. 3%,定量泵+伺服电机系统节能56. 4%,且这2种系统的节能效果根据所生产制品的不同而有所差异。     

节能型高效伺服注塑机设计

根据传统注塑机的特点，开发了节能型高效伺服注塑机，该机采用以交流永磁伺服同步电机为动力源的电液混合式驱动系统，采用交流同步伺服控制器和永磁式同步伺服马达作为控制主核心的控制系统。通过能耗对比实验表明，电机完全根据实际工况进行自动调速，大大降低了辅助工段的能量损耗，节能效果高达50％-60％。空载和满载（14MPa）响应时间小于180ms，生产效率提高20％以上。     

基于PID控制器对轮胎制造用氮气的循环利用

轮胎的氮气硫化中,为了降低氮气的成本,设计了氮气循环回收利用系统。在氮气循环回收系统中,首先描述氮气循环回收利用的结构、控制参数的确定、静态特性以及以含氧量为控制对象的智能PID控制器的设置办法。然后介绍回收氮气压力的控制过程及PID控制器与变频器的联接方式。氮气得到有效回收。     

Relaxation patterns in powder injection mouldings made with repeated flow Reversals

Injection moulding suspensions based on both high and low molecular weight organic vehicles and incorporating both spherical and anisotropically shaped particles were prepared. A double end-gated rectangular bar cavity was used for injection moulding. Conventional mouldings were made by injection from one gate followed by static hold pressure. Modulated pressure mouldings were made in the same way but reciprocating flow was induced between the gates during solidification. The mouldings were sectioned, polished and heat treated whereupon a pattern of rings emerged in relief preserving the history of flow reversals as the solid-liquid interface advanced from the mould walls.     

Experimental study of weldline caused by flow lead effect in gas assisted injection moulded parts

Abstract

Gas assisted injection moulding has become one of the most important methods for the manufacture of plastic products. However, there are several unsolved problems that confound the overall success of this technique. The weldline caused by the flow lead effect in the polymer melt is one of them. In this report, an L′18 orthogonal array design based on the Taguchi method has been conducted to investigate the flow lead induced weldlines in gas assisted injection moulded parts. A plate cavity with a gas channel on the side was used for moulding. Experiments were carried out on an 80 t reciprocating screw injection moulding machine equipped with a high pressure gas injection unit. After moulding, the depth of the weldline was measured. For the factors selected in the main experiments, melt injection temperature and mould temperature were found to be the principal factors affecting the weldline depth of gas assisted injection moulded parts. Experimental investigation of a gas assisted injection moulding problem can help in better understanding the weldlines caused by flow lead effects, so that steps can be taken to optimise the surface quality of moulded parts. PRC/1755     

汽车档位杆注塑模具冷却系统设计及优化

由于汽车档位杆属于薄壁中空零件,且采用的是收缩率较大的POM材料进行注塑成型,上、下模具和4个侧面抽芯方向的形状差异较大,因此,各个模具组件之间的温度梯度较大,在注塑成型过程中,经常会发生充填不足和缩水变形等工艺缺陷问题。针对塑件的结构特点设计了多层次的模具冷却系统,使复杂侧抽芯部件得到充分均衡的冷却,在细长抽芯内部设置螺旋隔片使细长抽芯零件也能够得到同步冷却,减少凝固结晶产生的应力,避免零件的翘曲变形和关键部位尺寸精度产生缺陷。应用模流分析技术对注塑过程中各层次的冷却回路工作情况进行数值分析,改进冷却系统结构,提高产品质量并缩短生产周期。     

Flow behaviour of rubber in capillary and injection moulding dies

This study is concerned with the flow behaviour of a rubber compound in capillary and injection moulding dies in the temperature range of 80–120°C. The injection moulding die designs had a tapered angle ranging from 40° up to 150°. The rheological characterisation of the rubber compound in the capillary dies showed that rubber slips at the wall, and this was modelled with an appropriate slip law. The pressure drops in the system were measured for all tapered dies. Numerical simulations were then carried out with a purely viscous (Carreau) model and a multimode viscoelastic (K-BKZ) model. The results showed a good agreement with the experiments for both the capillary and the injection moulding dies, provided that slip is included in the simulations as determined experimentally.     

甘蔗收割机切割系统耙齿注塑成型翘曲变形分析

针对传统甘蔗收获机切割系统甘蔗喂入困难问题,设计了新型的甘蔗耙齿,将其安装在切割器上,以甘蔗收割机切割系统耙齿制品为研究对象,为了避免注塑成型方案加工使新型耙齿易出现翘曲的现象,文章利用Moldflow模流分析软件和正交试验方法,研究了保压压力、保压时间、熔体温度和模具温度对制品翘曲的影响。结果表明,保压压力对翘曲缺陷影响最大,保压时间的影响最小。根据正交试验结果,选择了最优工艺对翘曲进行了优化,结果显示,当保压压力为120 MPa,保压时间为12 s,熔体温度为220℃,模具温度为55℃时,耙齿的翘曲量最小。     

聚碳酸酯厚壁制品的注射成型

通过分析聚碳酸酯的工艺特性,针对特定的厚壁注塑制品,在材料的选择上要考虑熔体流动速率、含水量等;在设备的选择上要考虑螺杆形式、压缩比、长径比等方面;在模具的设计上要考虑采用的浇口形式、大小、脱模斜度、排气、模具预热及冷却等;在注塑工艺上可通过调整料筒温度、注射压力、速度、模温等来设置合理的工艺参数。通过以上一些措施,可以使特定的厚壁制品达到要求。     

陶瓷胶态注射成型中压力的影响

陶瓷胶态注射成型是一种结合了凝胶注模成型和注射成型优点的新成型工艺。不同于凝胶注模成型中通过温度诱发反应,在胶态注射成型中是利用温度与压力共同作用引发陶瓷浆料固化。采用自行研制的凝胶点测试装置,研究了不同温度条件下压力对氧化铝浆料固化过程的影响,发现提高压力能促进浆料固化,不仅能缩短其聚合诱导期,而且能加速固化过程。此外,探讨了胶态成型的作用机制,为胶态注射成型的自动化设计提供了相关工艺参数。     

Characteristics of mould separation and its effects on qualities of thin wall injection moulded parts

Abstract

Precision injection moulding of thin walled parts has become an important concern in the computer, communication, and consumer electronics plastics industry. Previous studies in precision injection moulding control focus on the injection screw and the associated operations. In the present study, the influence of relevant parameters including injection speed, melt temperature, mould temperature, filling-packing switchover, and packing pressure on the mould plate separation under different clamping pressure were investigated as part of precision moulding control. A two cavity tensile test specimen mould equipped with four linear variable displacement transducers across the parting surfaces of the mould was used. A computer based monitoring system was built to detect the mould separation signals. Mould separation can also be identified from part weight and thickness variation and exhibits relevant correspondence with them. It was found that owing to the high injection speed required for thin wall moulding, mould separation is not negligible. In all situations, mould separation decreases with increasing clamping pressure. As melttemperature andmouldtemperatureincrease,mouldseparationincreases, resulting in an increase in part weight and thickness. Similarly, when packing pressure and injection speed increase, mould separation also increases. Earlier switchover from filling to packing can decrease mould separation as well as part weight and thickness. Among all the parameters studied, packing pressure exhibits the greatest influence on mould separation and on the associated weight and thickness change. This influence also becomes larger when the moulded part becomes thinner, owing to the larger injection moulding pressure. PRC/1746