塑料模现状及发展趋势

我国塑料模的发展,极其迅速,现已具相当规模。无论是设计水平、加工制造技术,还是 CAD 技术都有了明显提高。本文简明扼要地介绍了国内外塑料模的现状、发展趋势、市场预测,以及“九五”国家规划目标与对策。     

注射成形Fe-50%Ni软磁合金的研究

Fe-50 %Ni合金是一种典型的高磁导率和低矫顽力的软磁材料,有着广阔的应用前景.本次实验采用注射成形方法制取Fe-50 %Ni,研究了在注射成形工艺中烧结工艺对最终产品性能及微观组织的影响,并分析了影响产品磁性能的一些主要因素.实验表明,烧结温度的提高和烧结时间的延长能够较好改善产品的力学性能;密度是影响产品磁性能的主要因素,杂质(主要指(C、O、N)的含量和晶粒尺寸对剩磁、磁导率和矫顽力也有较大的影响;通过注射成形方法制取的Fe-50 %Ni,其性能要优于采用传统粉末冶金方法制造的Fe-50 %Ni.     

An Approach to Modelling the Forming Process of Sheet Metal-Polymer Composites

Polymer Injection Forming (PIF) and Polymer Injection-Compression Forming (PICF) are new manufacturing technologies for sheet metal-polymer macro-composites, which result from the combination of injection moulding and sheet metal forming. In these processes, a metal blank is formed inside an injection mould by using the pressure of the molten polymer that, after cooling, permanently bonds to the metal sheet creating a fully finished product in only one production step. This paper presents a calibrated multi-physics numerical model of the processes that proves to be suitable to investigate the mutual metal-polymer interactions and to provide a reliable tool in designing the process as well as its control.     

注射成形粘结NdFeB磁体:工艺·性能·应用

综合介绍了几种适于注射成形粘结NdFeB磁体的磁粉制备方法及特点；讨论了粘结剂、改性剂及磁场取向对注射成形NdFeB磁体最终磁性能的影响及其应用市场。在此基础上，指出了今后开展研究工作的方向。     

提高塑封双列直插式光耦合器绝缘耐压的设计和工艺要点

介绍了研制出其性能达国际先进公司同类产品水平的塑封双列直插式光耦合器的工作原理和提高绝缘耐压的技术难点，从引线框架设计、加工精度控制、内包封材料选型、理想内包封形状控制、塑封气密性的实现、环境条件的完善等方面讨论了提高绝缘耐压的设计和工艺要点。     

采用一次模压成形工艺生产高性能烧结NdFeB磁环

介绍了采用一次模压成形工艺批量生产高性能烧结钕铁硼磁环的新工艺 ,指出了目前该工艺仍存在的一些问题 ,同时概述了该工艺的应用前景     

Residual Stress Simulation of Injection Molding

In this study, distribution and history of residual stresses in plaque-like geometries are simulated based on linear thermoviscoelastic model, which helps to understand the mechanics and evolution of the residual stresses in the injection molding process. The numerical calculation of direction, combined with the specified boundary conditions. Results show that the stress variation across the thickness exhibits a high surface tensile value changing to a compressive peak value close to the surface, with the core region experiencing a parabolic tensile peak. Residual stress distribution throughout the thickness is almost same along the flowpath and the final residual stresses value near the gate is lower than the value near the end of flowpath.     

Optimal control of accelerator concentration for resin transfer molding process

Resin cure following mold filling is an essential element in resin transfer molding. To fabricate a composite part with high dimensional stability and minimize residual stress, uniform resin cure should be achieved. This study considers a three-part resin system composed of epoxy, hardener and accelerator. The cure kinetics can be controlled by the accelerator concentration at the injection gate. A numerical method that can predict degree of cure distribution based on accelerator concentration at the gate was proposed. The degree of cure distribution is obtained by solving the resin flow, heat transfer, accelerator concentration and cure problems sequentially. Utilizing this numerical method, an optimal variation of accelerator concentration during mold filling was sought by solving a constrained optimization problem. The effect of accelerator control on degree of cure distribution was investigated and its validity was examined for two different geometries.     

CHA无机凝胶体系的研究及应用

过去低渗油藏调剖，注入性和堵塞性很难统一，新研制的CHA无机凝胶体系是一种易注入、堵塞能力强的调剖剂，而且成胶时间在一定范围内可控。研究了配比、温度对CHA无机凝胶体系成胶时间的影响，成胶前的注入性，成胶后在高温高盐条件下的堵塞能力，得到了可应用于现场的CHA无机凝胶体系。该调剖剂在濮城油田沙三段和文卫结合部等高温、高盐低渗油藏应用后，取得了很好的效果。     

W-Ni-Cu高比重合金注射成形烧结收缩及性能的研究

研究了W-Ni-Cu高比重合金注射成形工艺过程收缩率和性能。比较了模具尺寸、注射坯尺寸、烧结坯尺寸，及烧结阶段各方向收缩率的关系，发现实际收缩与理论预测收缩率较为一致，但在厚度方向存在与其他方向收缩不一致的情形，这与由重力作用产生的塑料流动有关；还探讨了烧结坯密度与烧结条件的关系，测定了烧结坯的力学性能及断口形貌、金相组织，烧结坯在1400℃，90min烧结达到了99％的相对密度，断裂强度600MPa以上。