| 摘要 |
1. Process for making lost casting models, consisting of expanded foam beads, for the full-mould casting process, especially for the mass production of castings, wherein fine beads of an unfoamed intermediate containing blowing agent, especially polystyrene, are prefoamed and, in the case of the energy required for this purpose being introduced by steam, are then dried, and wherein the prefoamed foam beads are introduced into a foaming mould, which preferably corresponds to the contours of the casting to be made, and are heated and finally foamed therein by introducing a heat transfer medium, characterized in that the prefoaming is carried out at such a high degree of prefoaming, especially with consumption of all the available blowing agent, that the blowing agent content remaining in the foaming mould is no longer sufficient for final foaming, and in that, immediately after prefoaming has been completed, the atmosphere surrounding the prefoamed material is extracted and additional blowing agent for forming a blowing agent atmosphere is fed in. |
