POM塑料典型制品注塑工艺探讨

介绍了POM塑料的注塑成型技术，结合典型产品的模具设计，成型工艺进行了分析讨论；并对POM塑料制品生产中的缺陷、原因及解决方法进行了论述。结果表明，POM作为工程塑料，在热水器配件中应用效果好，而且注塑成型中传统的模外脱螺纹方法，适用于特殊结构的制品加工，同时可以使模具结构大大简化。     

聚对苯二甲酸乙二醇酯(PET)注塑成型技术

pet因透明度高、阻隔性强、成本低等优点正被广泛用于各个领域，本文重点阐述了PET的特性、PET注塑模具设计、注塑成型工艺参数设置，以及注塑成型过程中常见注塑缺陷及解决办法，对PET注塑成型的具有理论和实践的指导作用。     

注塑工艺对ASA光泽的影响

采用双螺杆挤出机加入消光剂等助剂制备了不同光泽的高耐候丙烯腈–苯乙烯–丙烯酸酯塑料(ASA),并研究了注塑温度、注射速度、模具温度、保压压力以及保压时间等注塑工艺对ASA注塑制品表面光泽的影响。结果表明,消光剂在ASA中有很好的哑光效果,通过控制其添加量可以获得力学性能和低光泽综合性能优异的哑光ASA。注塑工艺对ASA光泽研究结果显示,模具温度和注塑温度是影响ASA表面光泽的最主要工艺参数。在合理的注塑加工范围内,适当地提高注塑温度、模具温度和保压压力,以及适当地延长保压时间可以获得低光泽效果优异的注塑件。     

注塑制品常见表观缺陷产生原因及其对策

注塑成型是最重要的塑料成型方法之一,它的最大优点是可以一次成型结构复杂的制品,应用很广。但注塑制品在成型过程中常会出现各种缺陷,从影响注塑制品质量的几个因素(材料、成型工艺、模具设计、制品设计)着手,分析了注塑制品常见的表观缺陷、产生的原因及其对策。     

聚砜注塑工艺及制品缺陷对策

介绍了聚砜(PSU)的结构、性能,并结合制品设计、模具设计等对PSU的注射成型要点进行了讨论。详细分析了PSU的注塑工艺参数,系统阐述了PSU在注射成型中常见的缺陷及解决方法。     

高流动性共聚聚丙烯的开发与应用现状

介绍了高流动性共聚聚丙烯在注塑制品中的应用优势以及国内外高流动性共聚聚丙烯开发生产及应用现状。高流动性共聚聚丙烯在流动性提高的同时，产品刚性和韧性达到了很好的平衡，综合性能优异，在注塑过程中可缩短加工周期，降低加工温度、注塑压力和能耗。成型相同的薄壁制品时，熔体流动速率为65g／10min的该类产品比传统熔体流动速率为35g／10min的产品注射温度可以降低20～50℃，成型周期减少27％，由于其优良的加工性，可满足大型薄壁注塑制品的生产及应用需要。     

Arkema推出高效MBS抗冲改性剂

法国Arkema（阿克玛）公司推出MBS（甲基丙烯酸甲酯／丁二烯／苯乙烯共聚物）抗冲改性剂Clearstrength 859．作为其Clearstrength系列产品的新增牌号，特点为低光泽、高效，应用目标为PVC注塑制品、低光泽板材和型材。与传统低光泽抗冲改性剂相比，用Clearstrength 859的最终制品冲击强度提高了20％。     

影响注塑制品设计的因素分析

文章从注塑制品应满足的使用功能和寿命要求出发,详细论述了材料性能,制品结构,模具设计与制造,注塑工艺等因素对制品设计的影响,并针对不同情况给出了相应的解决方法。     

热成型工艺的解决方案

成功的塑料热成型工艺解决方案,要求对加工工艺、模具设计、材料性能等因素进行全面综合分析。众多的热成型加工厂商往往只着眼于调整和改进工艺,以此来解决生产过程中所遇到的各种制品缺陷问题。其中采取的措施包括:试图延长加工循环周期、二次加工工序、或者通过改良设备装置     

聚丙烯制品外观缺陷及解决措施

介绍聚丙烯制品常见的外观缺陷，从理论上分析各种缺陷产生的原因，并结合实际讨论注塑工艺条件、模具结构、设备对聚丙烯制品外观质量影响。结果表明，通过调整注塑工艺条件、改变模具结构及设备状况即可避免聚丙烯制品表面缺陷的出现，改善制品外观质量。     

Variations in surface gloss on parts made by gas assisted injection moulding

Abstract

Gas assisted injection moulding has proved to be a breakthrough in moulding technology for thermoplastic materials. However, there are still unsolved problems that limit the overall success of this technique. The aim of this work was to study the phenomenon of gloss variations occurring across the surfaces of gas assisted injection moulded parts. Experiments were carried out on an 80 t injection moulding machine equipped with a high pressure, nitrogen gas injection unit. The materials used were pigmented acrylonitrile/butadiene/ styrene and polypropylene. A plate cavity with a gas channel across its centre was used to mould the parts. Various processing parameters were varied: melt temperature; mould temperature; melt filling speed; short shot size; gas pressure; and gas injection delay time. After moulding, a glossmeter was used to determine the effects of these processing parameters on the surface gloss profiles of the parts. A roughness meter and scanning electronic microscope were also employed to characterise the surface quality of moulded parts. In addition, a numerical analysis of the filling process was carried out to help better understand the mechanisms responsible for the phenomenon of surface gloss variations. It was found that the surface gloss difference occurs mainly in the transition area between channel and plate in the moulded parts, which might be the result of the shear stress gradient in the polymer melt during the filling process. Surface roughness of moulded parts might also be another factor resulting in the gloss difference problem. PRC/1720     

透明聚丙烯的注射成型技术

本文介绍了透明聚丙烯的注射成型特性。从制品与模具的设计、成型设备、成型工艺条件三个方面对影响制品透明性的因素进行探讨,并提出了建议     

Micromoulding: process characteristics and product properties

Abstract

Key aspects of the technology and challenges associated with the micromoulding process are discussed. The apparent shear and extensional viscosity behaviour of a polyacetal at high wall shear rates have been measured using inline capillary rheometry on a commercial micromoulding machine and a larger servoelectric injection moulding machine; the polymer behaved predictably at shear rates in excess of 10⁶ s^-1. Initial moulding trials indicated that a stepped plaque and 0·25 mm thick rectangular plaque mouldings filled in a satisfactory manner, but a thicker plaque cavity exhibited a jetting flow into the cavity.

A data capture system capable of measuring multiple process dynamics at high sampling rates (up to 50 kHz per channel) allowed detailed process measurements taken during moulding of the stepped plaque moulding. Atomic force microscopy of the moulded products showed different surface finishes on each step of the stepped plaque moulding. Topography scans of the 0·25 mm thick rectangular plaque moulding showed that mould surface features with length scales of the order of a few micrometres were well replicated on the moulded product and the quality of the surface finish is dependent on the melt pressure during moulding.     

热塑性聚氨脂过滤器壳制品常见的缺陷及解决方法

介绍了利用热塑性聚氨酯弹性体(TPU)原料制造过滤器壳体注射成型的工艺流程。对生产过滤器壳体制品的缺陷及解决方法进行了深入的分析、总结。列举了过滤器壳体注射成型过程中常见的欠注、流痕、银纹、溢料、制品应力和缩凹变形等缺陷,从影响制品质量的各个因素,如注射成型工艺、模具及产品设计等方面入手,分析其成因并提出了相应的解决方法。     

气体辅助注射成型技术及其制品设计

介绍了气体辅助注射成型技术和气体辅助注射成型的制品设计。     

混合注射成型技术应用日广

介绍多组分注射成型工艺技术等混合注射技术,目前已被越来越多的塑料制品生产厂家采用,可生产出多种符合时代要求的塑料制品,如汽车零部件以及电子通汛产品部件等。混合注射成型技术将成为最重要的塑料制品加工工艺之一。     

脉动压力诱导注射成型加工技术

介绍脉动压力诱导塑料制品注射成型技术以及实现该技术的塑化注射装置。模块化设计的液压激振装置结构简单,输出功率高,方便对传统塑料注射机进行改造。新技术具有加工能耗低,制品品质高等特点,通过控制脉动频率与振幅可以对制品的品质进行调控。     

利用CAE技术解决注塑件的翘曲问题

翘曲是注塑件生产中常见的问题,利用CAE技术解决注塑件生产中出现的翘曲问题已经越来越被业界所认同。本文通过实例的分析,说明如何运用MPI(MoldflowPlasticInsight4.1)分析软件解决实际生产中所遇翘曲问题。     

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     

Evaluation of the moulding process for production of short-fibre-reinforced C/C-SiC composites

For the production of C/C-SiC brake discs via the liquid silicon infiltration method (LSI), the hot pressing process is the state of art technique for the moulding of the CFRP composites. This technique consists of several manual steps which increase production cost. The overall cost can be reduced by implementing injection moulding process.In this paper the influence of the moulding process (hot pressing, injection moulding) on the properties of semi-finished and final products during the production of short-fibre-reinforced C/C-SiC composites by means of the LSI process are examined. The starting polymer is chemically characterised. Carbon-fibre-reinforced plastic (CFRP) composites are fabricated by hot pressing, as well as injection moulding process. The CFRP composites are converted into porous C/C composites by pyrolysis. Liquid silicon is infiltrated to form dense C/C-SiC composites, which are further investigated during the course of this paper. Significant differences in properties of the composites are discussed.