蒸汽加热变模温注射成型数值模拟与结果分析

采用Moldflow软件对变模温注射成型过程进行数值模拟。利用蒸汽加热和冷却水冷却的变模温注塑工艺,研究不同蒸汽加热时间下注塑位置处压力以及制件冷凝层的变化规律,同时分析了制件表面和模具型腔表面的热响应规律。结果表明,相比于传统注射成型工艺过程,变模温注射成型通过提高注塑充填过程中模具温度,使得制件冷凝层出现在充填阶段之后;随着模具加热时间从10、15、25 s增加到40 s,注塑位置处最大注射压力从87.0608、84.6064、79.6863 MPa减小到74.4342 MPa,大大提高了熔体注塑充填过程中的充填能力;通过不同的蒸汽加热时间,制件表面和模具型腔表面可以获得不同的温度值,同时通过模拟获得了传热系数对制件表面温度的影响。     

高光注塑成型模具热响应研究

高光无痕注射成型技术是一种新兴的注射技术,能够消除塑件表面熔接痕等缺陷,表面可以达到镜面效果,免去二次喷涂。本文通过建立模具的二维几何模型,利用ANSYS模拟了加热、冷却过程,获得了模具表面及熔体中心层的热响应和温度分布情况。同时对比分析了常规注塑与高光注塑成型两种成型工艺,通过加热、冷却时间及温度分布等结果的对比,验证了高光注塑的优越性。     

高光无痕注塑成型模具热响应的研究

高光无痕注射成型技术是一种新开发的注射技术,能够消除塑件表面熔接痕等缺陷,表面可以达到镜面效果,免去二次喷涂。通过建立模具的二维几何模型,应用ANSYS模拟了加热、冷却过程,获得了模具表面及熔体中心层的热响应和温度分布情况;对比分析了常规注塑与高光无痕注塑两种成型工艺;通过加热、冷却时间及温度分布等对比,验证了高光无痕注塑的优越性。     

变模温注塑技术的研究与应用分析

变模温注塑料是一种基于动态模温控制策略的注射成型技术,可根据不同工艺阶段的特点,随时调整模具温度,可在不降低生产效率的同时有效提升塑件的品质.在深入回顾变模温注塑技术研究发展的基础上,分析比较各种技术的优缺点和应用范围.构建了蒸汽辅助加热变模温注塑系统,实现了平板电视机面板的高光无熔痕注塑生产.     

基于ANSYS的LED电视面壳高光模具方案设计

基于高光成型工艺原理,为实现LED电视面壳的高光效果,提出采用油加热、油冷却方式对其型腔表面进行变模温控制。构建基于多种不同模具材料和结构变模温注塑工艺分析模型,利用ANSYS对其加热响应、冷却过程进行数值模拟。最终采用以AMPCOLOY 972作为模具材料且带隔热方式的高光模具结构方案。     

蒸汽直接加热模腔的高光注塑技术研究

提出了蒸汽直接加热模具型腔表面的高光注塑新方法,研制了蒸汽直接加热模具型腔的高光注塑模具及模具温度控制机.该装置将高温蒸汽直接通入模腔,使模腔表面达到所需的温度,然后通入高温干空气,吹除模腔内残留的冷凝水,再注射、保压、冷却、开模,完成一个注塑周期.该方法使动定模模面得到均匀加热,熔融科前锋温度和速度高,且只加热模面以...     

高光注射成型及其关键技术

简述了高光塑料产品注射成型技术的原理和流程,介绍了高光塑料材料、高光模具材料与结构、模面加热方法与模具温度控制系统等关键技术及其应用,并分析了高光注射成型发展趋势.     

HIPS在模具型腔中流变缺陷的形成机理分析

基于高抗冲聚苯乙烯(HIPS)塑料熔体在模具型腔中的流变特性,以空调框罩的注塑工艺为研究对象,对注射成型的工艺系统及HIPS材料特性进行了深入分析。针对保压及冷却过程中的温度场变化对缩痕形成进行建模分析。结果表明:熔体凝固层温度与模具型腔壁温度的温差越大,缩痕缺陷越大。同时又对热残余应力导致的缩痕进行了建模分析,得出即时降温速度和瞬时温度梯度越大,较大的应变速率将会导致更大的缩痕缺陷产生。并通过注射试验验证了空调框罩的成型工艺。     

车载蓝牙外壳高光无痕注射CAE分析及参数优化

以车载蓝牙外壳为例,研究了局部密孔制件与普通制件高光注射成型的区别。利用Moldflow软件结合正交方法、数值模拟和数据处理技术,对高光无痕注射成型工艺进行了模拟分析。针对高光成型指标(翘曲变形、体积收缩率和熔接痕),研究了模具温度对高光制品品质的影响,得出高光制品品质随温度的升高而改善。并在此基础上模拟了熔体温度等多因素对高光制品体积收缩率和翘曲变形的影响,优化了工艺参数。     

计时器盒盖注射成型模具的设计

从制件和所用原材料分析入手，探讨了计时器盒盖的注射成型工艺，进行了型腔和型芯的尺寸计算与强度计算，以及注射模具浇注系统的设计。通过模具设计、制造和调试，成功地实现了计时器盒盖的成型，     

成型温度对PP和ABS试样表面颜色和光泽度的影响

以K31皮纹为例,研究了成型温度对聚丙烯(PP)和丙烯腈-丁二烯-苯乙烯塑料(ABS)试样表面颜色和光泽度的影响。结果表明,随着模具温度和熔体温度的升高,无论是PP还是ABS,其试样颜色的L值均呈增加趋势而光泽度均呈降低趋势,且ABS试样的光泽度降低程度比PP试样高。注塑温度和模具温度升高,材料的流动性提高,冷却时间延长,试样复制模具皮纹的能力提高,使得PP和ABS试样表面皮纹深度均有所增加,从而使试样的光泽度降低、同时L值升高。与PP结晶型材料不同,ABS作为非结晶型材料,其流动性受温度影响更为显著,随着成型温度的升高,使得ABS试样的光泽度降低的程度更大。     

基于Moldflow的汽车盒体件注塑模具设计

分析了汽车盒体塑件的成型工艺,通过Moldflow软件对熔体的填充时间、注射压力、熔体前沿温度、气穴及熔接痕位置等进行了分析,根据模拟分析结果设计了一副三板式潜伏式浇口注塑模具,并对模具进行了合理的选材和热处理。结果表明,模具设计合理,运动平稳,成型的塑件尺寸精度高,表面无飞边、熔接痕、气穴等质量缺陷。     

Effects of injection‐molding conditions on the gloss and color of pigmented polypropylene

The effects of processing conditions on appearance characteristics of injection‐molded mineral‐filled polypropylene (compounded with pigments giving differing intensities of a beige color) have been studied; characteristics studied included gloss, color, and texture. A mold cavity embossed with smooth, fine, and coarse surface patterns was used. In‐mold rheology and gate‐seal analysis were used to select the filling and postfilling processing parameters. Interest was focused on the effects of filling rate, holding pressure, and mold temperature on the appearance characteristics, and a significant influence of these processing conditions on the gloss and color was found. For all the surface patterns examined, a better replication of the mold texture was obtained with a low melt viscosity at a high shear rate (high injection speed or short injection time) and a high mold temperature. This gave a higher gloss in the smooth surface regions and a lower gloss in the textured regions. An increase in the holding pressure had an effect similar to but smaller than increasing the filling rate or mold temperature. The gloss (or surface topography) had a significant effect on the color; an increase in gloss was associated with an increase in the color coordinate b* and a decrease in the lightness L*. POLYM. ENG. SCI. 45:1557–1567, 2005. © 2005 Society of Plastics Engineers     

Multiobjective optimization design of heating system in electric heating rapid thermal cycling mold for yielding high gloss parts

An optimization design method is developed for the electric heating system in rapid thermal cycling molding (RTCM) mold. First, a multiobjective optimization model is established, in which the distance between the mold cavity surface and the center of heating elements and the number and power density of heating elements are the design variables, the required heating time t_h and the highest cavity surface temperature T_max at time t_h are the objective functions. Then, an optimization strategy consisting of design of experiment, finite element analysis, artificial neural network (ANN) and response surface methodology (RSM) models, and Pareto‐based genetic algorithm is proposed to solve the multiobjective optimization model. Finally, the optimization strategy is applied for the design of the heating system for an automotive spoiler blow mold. The results show that the temperature distribution uniformity on the blow mold cavity surface is obviously improved and high heating efficiency is also ensured with the optimized design parameters. Moreover, the ANN model exhibits its superiority over the RSM model in terms of modeling and predictive abilities. A RTCM blow mold with the optimized electric heating system is constructed and successfully utilized to mold high gloss automotive spoiler. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131, 39976.     

注塑模具设计过程中浇口尺寸对塑料制品力学性能的影响

以高密度聚乙烯（PE-HD）为原料,采用自行设计加工的一套1模4腔注射标准试样模具进行注塑,通过调整熔体温度、模具温度和注射压力等工艺参数,考察了不同浇口截面尺寸的模具对注塑样品拉伸、冲击和弯曲性能的影响。结果表明,模具浇口截面尺寸修改后,注射试样的力学性能明显提升,其中,拉伸强度、冲击强度、弯曲强度和弯曲模量最高分别提升了3.40 %、79.86 %、18.11 %和113.36 %;模具浇口修改后注塑所的样品充填饱满,无塌陷等缺陷;修改浇口后的模具设计整体结构布局合理,可为同类标准测试样的成型模具设计提供有益借鉴。     

Thermal response of an electric heating rapid heat cycle molding mold and its effect on surface appearance and tensile strength of the molded part

Rapid heat cycle molding (RHCM) is a newly developed injection molding technology in recent years. In this article, a new electric heating RHCM mold is developed for rapid heating and cooling of the cavity surface. A data acquisition system is constructed to evaluate thermal response of the cavity surfaces of the electric heating RHCM mold. Thermal cycling experiments are implemented to investigate cavity surface temperature responses with different heating time and cooling time. According to the experimental results, a mathematical model is developed by regression analysis to predict the highest temperature and the lowest temperature of the cavity surface during thermal cycling of the electric heating RHCM mold. The verification experiments show that the proposed model is very effective for accurate control of the cavity surface temperature. For a more comprehensive analysis of the thermal response and temperature distribution of the cavity surfaces, the numerical‐method‐based finite element analysis (FEA) is used to simulate thermal response of the electric heating RHCM mold during thermal cycling process. The simulated cavity surface temperature response shows a good agreement with the experimental results. Based on simulations, the influence of the power density of the cartridge heaters and the temperature of the cooling water on thermal response of the cavity surface is obtained. Finally, the effect of RHCM process on surface appearance and tensile strength of the part is studied. The results show that the high‐cavity surface temperature during filling stage in RHCM can significantly improve the surface appearance by greatly improving the surface gloss and completely eliminating the weld line and jetting mark. RHCM process can also eliminate the exposing fibers on the part surface for the fiber‐reinforced plastics. For the high‐gloss acrylonitrile butadiene styrene/polymethyl methacrylate (ABS/PMMA) alloy, RHCM process reduces the tensile strength of the part either with or without weld mark. For the fiber‐reinforced plastics of polypropylene (PP) + 20% glass fiber, RHCM process reduces the tensile strength of the part without weld mark but slightly increases the tensile strength of the part with weld mark. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

基于Moldflow的高光无痕电视前壳注射模具设计

以液晶电视机前壳为例,结合制品的精度要求和模具结构特点,详尽分析高光无痕注塑模具流道系统、温度控制系统和复杂抽芯机构的设计方法,给出整套模具其它结构的设计要点。利用Moldflow软件,采用变模温工艺技术,对高光无痕注射成型工艺进行模拟分析,验证了流道系统和温度控制系统的控制效果。     

Mold replication in injection molding of high density polyethylene

In order to deepen the mechanisms at the basis of mold surface replication onto the molded plastic surface, a novel experimental approach is proposed. Up to 20 different mold surface textures were made by machining with repetitive patterns of peaks and valleys. Mold replication tests were performed by over-molding of high density polyethylene (HDPE) on steel inserts. The surface morphology of inserts and injection molded parts was acquired by surface analyzer, and all the main roughness parameters were extracted and compared as well as the geometrical profiles. Surface morphology was also measured on molded samples after thermal relaxation at 100°C. As expected, a strong correlation was found between the roughness of mold insert and molded part over the full experimented range. Profiles on the molded surface have the same repetitive pattern of the corresponding insert surface but with lower peaks, higher valleys, and a horizontal shrinkage. Comparing molded HDPE surface profiles before and after thermal relaxation, it was observed a similar change to the one highlighted between mold insert and molded part. This occurrence suggests that the final surface appearance of the molded part is also a function of the relaxation mechanism during or immediately after injection molding.     

汽车保险杠注塑模的开发

以注塑模开发流程为主线,简要介绍了汽车保险杠注塑模的设计(包括浇口、分型面、导向定位、冷却水道、材料、热处理及标准件)、模具加工、注射成型及制品检验的要点。对注塑模的开发,特别是汽车保险杠注塑模的开发具有重要的参考价值。     

Research on a New Variotherm Injection Molding Technology and its Application on the Molding of a Large LCD Panel

The polymer injection products produced by using the current injection molding method usually have many defects, such as short shot, jetting, sink mark, flow mark, weld mark, and floating fibers. These defects have to be eliminated by using post-processing processes such as spraying and coating, which will cause environment pollution and waste in time, materials, energy and labor. These problems can be solved effectively by using a new injection method, named as variotherm injection molding or rapid heat cycle molding (RHCM). In this paper, a new type of dynamic mold temperature control system using steam as heating medium and cooling water as coolant was developed for variotherm injection molding. The injection mold is heated to a temperature higher than the glass transition temperature of the resin, and keeps this temperature in the polymer melt filling stage. To evaluate the efficiency of steam heating and coolant cooling, the mold surface temperature response during the heating stage and the polymer melt temperature response during the cooling stage were investigated by numerical thermal analysis. During heating, the mold surface temperature can be raised up rapidly with an average heating speed of 5.4°C/s and finally reaches an equilibrium temperature after an effective heating time of 40 s. It takes about 34.5 s to cool down the shaped polymer melt to the ejection temperature for demolding. The effect of main parameters such as mold structure, material of mold insert on heating/cooling efficiency and surface temperature uniformity were also discussed based on simulation results. Finally, a variotherm injection production line for 46-inch LCD panel was constructed. The test production results demonstrate that the mold temperature control system developed in this study can dynamically and efficiently control mold surface temperature without increasing molding cycle time. With this new variotherm injection molding technology, the defects on LCD panel surface occurring in conventional injection molding process, such as short shot, jetting, sink mark, flow mark, weld mark, and floating fibers were eliminated effectively. The surface gloss of the panel was improved and the secondary operations, such as sanding and coating, are not needed anymore.