纤维增强塑料注射充模过程中纤维对模具的冲蚀磨损模拟

针对塑料模具在玻璃纤维冲蚀下造成的表面磨损问题,运用有限元软件ANSYS/LS-DYNA建立了模具材料多颗粒冲蚀有限元模型,进行三维显式冲击动力学计算,研究纤维在不同冲蚀速度和冲蚀角度下对模具的冲蚀规律,分析冲蚀机理。结果表明,玻璃纤维对模具的冲蚀过程以微切削为主;玻璃纤维对模具的冲蚀磨损率随着冲蚀速度的增加而增加,随着冲蚀角度的增加而呈现先增加后减小的趋势。     

纤维增强塑料注射充模过程中纤维对模具的冲蚀磨损模拟

针对塑料模具在玻璃纤维冲蚀下造成的表面磨损问题,运用有限元软件ANSYS/LS-DYNA建立了模具材料多颗粒冲蚀有限元模型,进行三维显式冲击动力学计算,研究纤维在不同冲蚀速度和冲蚀角度下对模具的冲蚀规律,分析冲蚀机理。结果表明,玻璃纤维对模具的冲蚀过程以微切削为主;玻璃纤维对模具的冲蚀磨损率随着冲蚀速度的增加而增加,随着冲蚀角度的增加而呈现先增加后减小的趋势。     

塑料模具的抛光处理

随着塑料制品日益广泛的应用，日化用品和饮料包装容器的外观往往需要塑料模具型腔的表面达到镜面抛光的程度。而生产光学镜片、镭射唱片等模具对表面粗糙度要求极高，因而对抛光性的要求也极高。抛光不仅增加工件的美观，而且能够改善材料表面的耐腐蚀性、耐磨性，还可以使模具拥有其它优点，如使塑料制品易于脱模，减少生产注塑周期等。因而抛光在塑料模具制作过程中是很重要的一道工序。     

我国轮胎模具制造和清洗技术概况

介绍我国轮胎模具的制造和清洗技术.轮胎模具在制造过程中的表面处理尤为重要,利用稀土复合渗表面处理技术可以以国产碳素塑料模具钢和低合金塑料模具钢替代昂贵的高合金精密塑料模具钢制造轮胎模具,大大降低生产成本.模具清洗方法中以干冰清洗法效果最佳,可在不损伤模具和无污染的前提下清洗细小的排气孔,并大大降低操作人员的劳动强度.     

塑料模具激光蚀纹机的关键技术研究

在塑料模具蚀纹加工中,传统的化学蚀刻方法存在污染大、加工周期长的缺点.基于最新的3D动态振镜扫描技术,对模具激光蚀刻原理进行了分析和探讨;对模具激光蚀刻工艺参数进行了优化;并设计了塑料产品常见的蚀纹图案.经过对模具激光蚀纹机的光学系统、机械系统、电气系统及软件系统等整体方案的设计及丁艺实验,证明模具激光蚀刻技术能满足了塑料模具加工企业的蚀纹和环保节能需求,同时为激光加工技术在塑料模具行业的广泛应用奠定基础.     

塑料模具的热处理和表面处理工艺

塑料模具主要包括低碳钢及低碳合金钢制模具,高合金渗碳钢制模具,调质钢制模具,碳素工具钢和合金工具钢制模具以及预硬钢制模具等几种。对于不同材质的塑料模具,由于其化学成分和力学性能各不相同,因此其所采用的热处理和表面处理工艺也大不一样。     

注塑模具表面改性技术的比较与选择

介绍几种主要的注塑模具表面改性技术，对表面处理、抗变形和精度、耐磨性、韧性、耐疲劳强度和表面粗糙度等方法进行了综合比较，最后提出了注塑模具表面改性技术的选择原则和方法。     

塑料模具光整加工技术及其合理选用

介绍了几种常见的塑料模腔表面抛光技术，针对塑料模的加工特点，结合模具光整加工的新进展，分析了如何合理选用塑料模具型腔光整加工技术。     

注塑模具表面改性技术的比较与选择

介绍了几种主要的注塑模具表面改性技术，从表面处理价格、抗变形和精度、耐磨性、韧性、耐疲劳强度和表面粗糙度等方面对各种方法进行了综合比较。最后提出了注塑模具表面改性技术的选择原则和方法。     

新型水溶性模具材料的性能及其应用研究

本文研究了一种新型水溶性材料AquacoreTM的性能,包括密度、线膨胀系数、压缩强度和压缩蠕变率。试验结果表明,该材料的密度ρ≈0.47g/cm3,线膨胀系数α=1.17×10-6/℃,190℃下的压缩强度为2.40MPa,压缩蠕变率ε<1.5%。同时开展了工程应用研究,使用这种材料的模具制造了碳纤维复合材料双峰波纹结构件,研究了模具表面粗糙度对产品表面粗糙度的影响以及脱模方式对产品的影响。测试结果显示,经表面处理后的水溶性模具的表面粗糙度Ra=1.2,产品接触面的表面粗糙度Ra=3.4。脱模过程中温度和水对产品影响不大,产品的吸湿量为0.98%。研究证实,这种水溶性模具特别适于制造结构复杂、脱模困难的复合材料制件。     

Mechanism and Simulation of Removal Rate and Surface Roughness During Optical Polishing of Glasses

Glass optics with ultra‐low roughness surfaces (<2 Å rms) are strongly desired for high‐end optical applications (e.g., lasers, spectroscopy, etc.). The complex microscopic interactions that occur between slurry particles and the glass workpiece during optical polishing ultimately determine the removal rate and resulting surface roughness of the workpiece. In this study, a comprehensive set of 100 mm diameter glass samples (fused silica, phosphate, and borosilicate) were polished using various slurry particle size distributions (PSD), slurry concentrations, and pad treatments. The removal rate and surface roughness of the glasses were characterized using white light interferometry and atomic force microscopy. The material removal mechanism for a given slurry particle is proposed to occur via nano‐plastic deformation (plastic removal) or via chemical reaction (molecular removal) depending on the slurry particle load on the glass surface. Using an expanded Hertzian contact model, called the Ensemble Hertzian Multi‐gap (EHMG) model, a platform has been developed to understand the microscopic interface interactions and to predict trends of the removal rate and surface roughness for a variety of polishing parameters. The EHMG model is based on multiple Hertzian contacts of slurry particles at the workpiece–pad interface in which the pad deflection and the effective interface gap at each pad asperity height are determined. Using this, the interface contact area and each particle's penetration, load, and contact zone are determined which are used to calculate the material removal rate and simulate the surface roughness. Each of the key polishing variables investigated is shown to affect the material removal rate, whose changes are dominated by very different microscopic interactions. Slurry PSD impacts the load per particle distribution and the fraction of particles removing material by plastic removal. The slurry concentration impacts the areal number density of particles and fraction of load on particles versus pad. The pad topography impacts the fraction of pad area making contact with the workpiece. The glass composition predominantly impacts the depth of plastic removal. Also, the results show that the dominant factor controlling surface roughness is the slurry PSD followed by the glass material's removal function and the pad topography. The model compares well with the experimental data over a variety of polishing conditions for both removal rate and roughness and can be extended to provide insights and strategies to develop practical, economic processes for obtaining ultra‐low roughness surfaces while simultaneously maintaining high material removal rates.     

Solid particle erosion behaviour of high purity alumina ceramics

The solid particle erosion behaviour of a high purity, cold isostatically pressed ceramics, CIP-Al₂O₃, is studied in this paper. The influence of particle properties, such as hardness and shape, on erosion is examined, as well as the effect of varying the impingement angle of the erodent stream on the weight loss of alumina ceramics samples. Therefore, the erosive wear behaviour was studied at five different impact angles (30°, 45°, 60°, 75° and 90°), using SiC and SiO₂ particles as erodents.The material loss during solid particle erosion is measured by changes in surface roughness, surface morphology and mass loss.The surface roughness and topography of the eroded Al₂O₃ ceramics were recorded using a profilometer.Scanning electron microscopy (SEM) was used to examine the features of eroded surfaces and to ascertain erosion mechanisms of the tested alumina samples.The results indicate that hard, angular SiC particles cause more damage than softer, more rounded SiO₂ particles. It was found that maximum erosion by both types of particles occurs at an impact angle of 90°.     

聚砜医疗干粉吸入器底座成型与注塑模设计

使用聚砜(PSU)塑料注射成型医疗干粉吸入器底座塑件。成型前,对PSU材料进行干燥处理的工艺参数为温度125~135℃,时间4~6 h,平铺,铺料厚度18~22 mm,含水量控制在0.1%以下。针对塑件的注射成型设计了1副一模一腔热流道两板注塑模具,使用单点热浇口进行浇注;模具分2次分型打开,1次用于塑件定模侧斜孔的抽芯脱模,1次用于塑件模腔的打开;型腔的表面粗糙度为0.4以上,排气孔的深度应控制在0.08 mm;针对塑件14个斜孔内壁的脱模,设计了定模斜杆复合顶出机构,针对14个斜孔外壁的脱模,设计了动模“万能斜顶”复合机构。运用CAE分析获得了模具中所需的成型时间为1.542 s,注塑压力为58 MPa。塑件成型后须退火处理,控制参数为空气浴,温度150℃,时间2~4 h。     

注塑模具模外脱模技术

以一副容器塑料件注塑模为例,对注塑机移模行程不足的塑料件注塑模,通过运用特殊的模外脱模技术,减小塑料件的加工机型.并叙述了该技术的结构特点和工作原理,介绍了模具材料、热处理及标准件.     

Erosion and Damage by Hard Spherical Particles on Glass

Solid particle impact of hard spherical particles on glass is of fundamental interest because of the presence of a number of different impact regimes. Understanding the impact of spherical particles is also a step toward modeling the behavior of rounded particles. This paper verifies theoretical models for the transitions between the different impact regimes and process parameters like erosion rate and surface roughness. The work also includes rounded particles. The transitions plotted in a so-called erosion map are validated with single-impact experiments. Data from erosion experiments are used to test the relations for the erosion rate and resulting surface roughness following from the models. Although the theoretical transitions compare reasonably with experiments, the models for erosion rate and surface roughness do not describe the experimentally found behavior. The models not incorporating the interaction between an impact and the damage remaining from earlier impacts might cause this deviation.     

Replication of plastic thin film by microfeature mould in large area hot embossing

Abstract

This study determines the replication property and surface roughness of microfeatures of a Ni mould that combines electroforming and large area hot embossing. The metal mould first uses a 4 in. silicon wafer to fabricate a master using the UV-LIGA method, and then applies the sputtering method to sputter the copper element as the seed layer on the surface of the master. The electroforming method is used to manufacture the Ni mould insert from the master with the seed layer. Finally, this study uses thin film of polymethyl methacrylate (PMMA) material to replicate the microfeatures of Ni mould insert by large area hot embossing. This study shows the replication properties and surface roughness of different microfeature shapes and sizes for the Ni mould insert and moulded PMMA on large area hot embossing. Experimental results show the average error in height of the microfeature is 0·61 μm for the Ni mould insert and moulded PMMA. The average error in surface roughness of the microfeature is 1·63 nm for the Ni mould insert and moulded PMMA. Experimental results show the good replication and surface roughness of moulded PMMA are replicated from the Ni mould insert by large area hot embossing.     

薄壁塑料件注塑模具设计

分析薄壁塑料件的设计过程,重点阐述根据模具结构、塑料件成型工艺、塑料件表面质量等来选择进胶方式和位置.通过优化塑料件壁厚和模具结构,实现生产可靠、尺寸稳定,质量满足要求,并总结此类塑料件的模具设计要点.     

线轴注塑模具设计

针对线轴的工艺特点及在生产中存在的平面翘曲、壁厚不均等问题，给出了实用模具结构。详细介绍了模具各系统及成型零件的设计，论述了模具的工作过程。模具结构紧凑，操作方便，可实现塑件的全自动生产，生产效率高，且成型塑件质量好。