Advances in Fusible Core Technique

Abstract

This chapter provides an overview of the basic production sequence of fusible core technology. A metal core is produced from a low-melting metal alloy, usually a eutectic tin/bismuth alloy. It is then inserted into an injection mold where it is encapsulated by the polymer. Afterwards, the core is removed in a heating bath where the plastic part comes into contact with a heated liquid medium, which is removed in the subsequent cleaning. Melting out of the core usually takes place in a bath of modified polyglycolether as heat-transfer medium. Melt removal can be assisted by induction coils to make this process step faster. Using conventional production plants and methods, the product designer has to make sure that the polymer is compatible to the modified polyglycolether at a temperature of 160 °C. Fusible core technology is generally in competition with manufacturing processes in which parts injection molded without undercuts are subsequently joined by welding, snap connection, screwing, or overmolding. If parts can still meet specifications, production costs for parts produced by multicomponent technology are often expected to be lower.