Method for the production of lost casting patterns for full mould casting out of expanded foam beads, preferably for the manufacture of mass-produced parts, and apparatus therefor

摘要

1. Process for producing consumable casting models comprising expanded foam-material beads, for full mould casting, preferably for making mass-produced castings, in which a finebeaded unfoamed propellant-containing initial product, in particular polystyrene, is prefoamed, and in which the prefoamed foam-material beads are introduced into a foaming mould preferably corresponding to the contour of the casting to be produced and are there warmed by introducing a heat transfer medium, in particular steam, and postfoamed, characterized in that in each mould foaming procedure an underpressure is produced when the heat transfer medium is introduced at a draw-off side of the mould cavity of the foaming mould which is opposite the introduction side and the heat transfer medium is drawn off thereby, the introduction side and draw-off side are changed repeatedly and after the change drawing off is continued until substantially clean fresh heat transfer medium comes to the draw-off side.