5.2 Selective LASER sintering
The mechanical properties of the moulding blocks produced by SLSm are similar to standard toolmaterials. The processing conditions used with these blocks were identical to standard injection moulding, this being a result of the good mechanical properties and thermal behaviour of the SLSm material allowing for rapid cooling of the parts. The temperature and pressure variation throughout one injection cycle is shown in Fig. 11 and are qualitatively distinct from the observed with the Neukadur moulding blocks. Similar evidence was reported by Roobaert et al. [31]. In spite of the good thermal and mechanical behaviour of the SLSm insert mouldings, some problems were observed during the ejection phase. The high roughness due to a nonpost finishing operation made difficult the ejection of moulding parts. In this condition occurs an important deformation into the mouldings during the ejection, which limits the automation of the moulding process and its productivity. In order to avoid these problems, a post finishing operations is essential.
6 Conclusions
Epoxy tooling and selective laser sintering were used to produce moulding blocks for hybrid moulds of a geometrically complex shape. The results suggest that resin moulding blocks made by epoxy tooling are not adequate for parts with extensive ribs or deep bosses. Small details can be reproduced accurately, although being prone to fast degradation upon moulding. Thus, epoxy tooling is more suitable to fabricate inserts with open and simple geometries. The processing conditions of hybrid moulds with epoxybased moulding blocks differ from those in conventional injection moulding. Thus, a suitable setup of the injection process must be previously estimated to achieve mouldings with adequate properties. An important issue on using hybrid moulds is the ejection of the parts, as adhesion or high stresses may lead to the destruction of mould details, such as deep bosses. Selective laser sintering is a direct rapid tooling technique suitable for moulding inserts. The processing conditions of hybrid moulds with this type of moulding blocks are identical to conventional moulds, but the detail and the finishing of the moulding surfaces is limited by the accuracy of the rapid prototyping process.
实验评估混合模的性能
摘要：复合模具是一种新颖的方法对快速模具注塑模具来说，结合常规加工的模具结构和快速原型技术成型块(型心和型腔)。在这项研究中，两种途径被用于生产成型块。选择性激光烧结的粉末钢基不锈钢(硬工具)和环氧树脂真空铸造(软工具)。实验研究是基于一个复杂的立体的商业零部件。模具是由聚丙烯材料制成，处理的情况是在线监测压力和温度的印象。对成型块的性能进行了分析和周期方面的热性能和结构完整性。环氧工具条更详细的细比选择性激光烧结更合适，但不是足够适合那些零件有广泛的肋骨或深的老板。结构完整性的低成本的环氧复合在弹出期间可能会受到影响，这表明需要对应力场的模拟在设计模具阶段。
关键词：混合型模具；成型块；注射成型；快速制模； SLS；环氧浇注
1 介绍
现代工业的重要部门，如汽车、城市家具或电器。都需要在市场迅速地推出新产品。这是随着对产品性能和产品个性化的更高要求[1]。也是一种趋势。从大规模生产移动到定制生产的小型系列产品[2]。需求的高精度注塑件产生少量与日益缩短开发周期导致集成设计方案从概念和发展到实际生产[3,4]。另一种方法为设计和制造工具的原型和短的塑料组件运行在一个竞争成本考虑的功能所提供的快速原型和工具最近(RPT)技术(5 - 8)和使用新材料在成型块(6、8 - 11]。构建模具与成型块装配式诉诸RPT的基础是混合模的概念(例如。[12,13])。因行业的看到有可能开发模具,依靠这些备选方案的模块和保留传统的制造技术,生产的标准模具结构[3、14]。本文介绍了利用两个RPT技术、环氧浇铸和选择性激光烧结生产成型块(核心和腔)的混合模的一个消费产品。主要目标是探讨相关的问题,使用这些方法来生产成型块RPT并评估复合模在词汇方面表现的结构和热行为。 复合模具混合模英文文献和翻译(4):http://www.751com.cn/fanyi/lunwen_3309.html