基于UG和Moldflow的垃圾桶上盖注塑模设计

针对传统注塑模具设计方法存在设计周期长、成本高且质量难以保证的不足,采用计算机辅助设计软件UG和有限元分析软件Moldflow相结合的方法进行垃圾桶上盖的注塑模具设计,创建了垃圾桶上盖的三维实体模型和模流分析有限元模型,通过对注射过程中流动分析和冷却分析的仿真,调整了垃圾桶上盖注塑模具的冷却系统结构,最后采用UG/MoldWizard模块创建了经过优化和调整的注塑模具实体模型.     

NX7 CAD技术在轮胎模具三维造型中的应用

阐述了运用NX7软件的CAD功能进行轮胎模具三维造型的过程,介绍了NX7软件实体造型功能和自由曲面造型功能在轮胎三维造型建模过程中的应用。     

模糊控制算法在实时监控系统中的应用

在烧结炉控制系统中,采用B型热电偶配合AD1674实现对烧结炉多点温度的采集,通过查表法达到非线性补偿的目的;控制系统采用C语言模块化编程;在温度控制方案上引入模糊控制算法.由Simulink仿真分析和系统实际运行情况可知:与传统PID算法相比,该算法的控制精度高,可达±0.1℃,系统的动态性能得到改善,鲁棒性增强.     

数控冲床上的浮雕模具设计与制造

介绍了数控冲床结构特点,阐述了数控冲床模具结构设计与制造工艺特点。数控冲床模具具有结构简单、形式多样和可编程排样等特点,模具的结构设计与制造具有较高的特殊要求。针对典型的浮雕模具采用一种实用的高效率的模具结构设计及其制造工艺,降低了数控冲床模具制造成本。     

稀土Ce对Al-12Si合金微观组织影响

本文以Al、Al-Si、Al-Ce高纯组元配置一定质量百分比的Al-Si-Ce合金,采用多功能真空电弧熔炼炉YSU-ZZ进行熔炼,使用铜模吸铸法制备样品并对样品进行金相显微镜、扫描电镜(SEM)及能谱分析(EDS).重点研究了Ce的加入量及冷却速度等因素对共品硅的大小、形状和分布的影响.研究表明快速凝同可以很好的细化共...     

Numerical study of macrosegregation formation of ingot cast in normal sand mold and water-cooled sand mold

Formation of macrosegregation of 5 t steel ingots cast in sand molds with and without water-cooled copper tube is simulated by solving macroscopic mass,momentum,species and energy conservation equations with the consideration of shrinkage formation.Predicted macrosegregation pattern of the ingots shows a fair agreement with the experimental data.Both calculations and experiments reveal that some positive segregation patches are formed at the bottom of ingot.With the water-cooled copper tube inserted in the ...     

Accelerated Mold Test on Dried Pine Sapwood Boards: Impact of Contact Heat Treatment

Abstract

We test the hypothesis that the combination of kiln drying of double-stacked boards and contact heat treatment will reduce the susceptibility of treated boards to colonization by mold fungi. Winter-felled Scots pine (Pinus sylvestris L.) sapwood boards were double-stacked in an industrial kiln in ‘‘sapwood out’’ and ‘‘sapwood in’’ positions. Dried samples were then contact heat-treated using a hot press at three different temperatures (140°C, 170°C, and 200°C) for three different periods (1, 3, and 10 min). An accelerated mold test was performed in a climate chamber where naturally mold-infected samples were used as a source of mold inocula. Contact heat treatment degraded the saccharides that accumulated at dried surfaces, and reduced the mold growth. The threshold temperature and time for inhibiting mold growth were 170°C for 10 min. However, for industrial application, the most feasible combination of temperature and time would be 200°C for 3 min. We concluded that double stacking/contact heat treatment used is an environmentally friendly alternative to chemicals for reducing mold on Scots pine sapwood boards.     

The effects of gas counter pressure and mold temperature variation on the surface quality and morphology of the microcellular polystyrene foams

In this study, we developed a foaming control system using the Gas Counter Pressure (GCP) combined with mold temperature control during the microcellular injection molding (MuCell) process and investigated its influence on the parts' surface quality and foams structures. The results revealed that under GCP control alone when GCP is greater than 10 MPa, part surface roughness for transparent polystyrene (PS) improved by 90%. When GCP increased, the skin thickness also increased, the weight reduction decreased and the average cell size reduced to about 30 μm. For black PS parts, when GCP is greater than 10 MPa, the part gloss reaches the same value as that molded by conventional injection molding. By increasing gas holding time, the cell density decreased and the cell size distribution became more uniform. The increase in amount of supercritical fluid foaming agent also increased the cell density. Applying mold temperature control alone with temperature in the range of 90–120°C (near T_g), the surface roughness improved by 65%. Increasing mold temperature decreased the skin thickness; however, the cell size distribution became significantly nonuniform. It was found that thin skin, small and uniform cell size as well as good surface quality can be achieved efficiently by simultaneous combining of GCP and mold temperature control. The proposed innovative approach may lead to a significant improvement and a more broad application for MuCell process. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

基于炉内辐射模型的加热过程分析

根据加热炉内辐射平衡关系,建立炉内辐射模型,计算产品温度;在此基础上,分析热电偶温度和布料密度等因素对产品加热温度的影响。分析结果表明,当热电偶安装位置不同、布料密度发生改变时,加热工艺需要进行相应的调整,才能满足产品加热要求。