Page 29

Issue 1/June 2017



LOST CORES FOR THE PRESSURE DIE-CASTING OF LIGHT METALS PRODUCTION OF HIGH QUALITY SALT CORES THROUGH HOT CHAMBER PRESSURE DIE-CASTING 轻金属压铸的型芯 通过热室压铸生产高品质的盐芯 压铸是非常有效的,并能提供高品质的铸件。 诸如泵、歧管、发动机元件等复杂内部空腔的 型芯是个老问题。常用的砂芯会被高压和高融 化速度会破坏。

Pressure die-casting is extremely productive and delivers high quality cast parts. However, an unresolved problem to date has been the use of lost cores for complex inner hollow cavities, e.g. with pumps, manifolds or engine components. High pressures and melt speeds destroy the sand cores conventionally used with other casting methods. Until now, only salt cores have proven themselves among the alternative technologies tested, and even then only in niches. Their advantages are dimensional accuracy, high strength, good de-moulding characteristics and very smooth surfaces. To date, production has predominantly taken place through pressure diecasting in cold chamber machines. However, the results have not always been satisfactory. An important obstacle is the high volumetric shrinkage of the salt when solidifying, which causes numerous cavities to form in the core. This can therefore break during pressure diecasting, resulting in faults.

替代技术的研究迄今只有盐芯得到证实,但也 处于起始阶段。其优点是尺寸精度高、强度 高、脱模性能好,且表面非常光滑。一直以来 大多通过冷室压铸机来制造。然而,结果并不 总是令人满意。一个重要的障碍是:在凝固过 程中盐的体积收缩高,由此在芯内形成许多缩 孔。因此,铸造过程中会有断裂,造成缺陷。 “We have utilised the advantages of the hot chamber pressure die-casting process for salt core production!” Dipl. Ing. Helmar Dannenmann (photo: Klaus Vollrath) “对于盐芯的制造我们信赖于热室 压铸工艺的优点!”硕士工程师 (FH)Helmar Dannenmann 如 是说(摄影:Klaus Vollrath)

因此,Oskar Frech 有限公司使用热室压铸 工艺而非冷室压铸来生产盐芯。其显著优点 是:模具中空气更少,浇注系统中的边缘外壳 形成可忽略,无需使用活塞润滑剂,铸造压力 更小,循环时间短。实验室试验和测试铸件表 明,这些盐芯牢固度高达五倍,且让铸造过程 安全可控。

The hot chamber pressure die-casting machine used in the Frech technique for the production of salt cores (photo: Klaus Vollrath)

Example: Complex sand core with sophisticated three-dimensional varied geometry for a sand mould (photo: Klaus Vollrath)

Frech 技术中心为制造盐芯而使用的热室压铸机(摄影:Klaus Vollrath)

模板:用于沙模的、带精密的三维几何结构变化的复杂砂芯(摄 影:Klaus Vollrath)

Foundry Planet Magazine

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Foundry-planet e-Magazine Diecasting-Dialogue ISSUE 1 | JUNE 2017  
Foundry-planet e-Magazine Diecasting-Dialogue ISSUE 1 | JUNE 2017