VERFAHREN ZUR ENTFERNUNG EINES WACHSAEHNLICHEN MODELLWERKSTOFFES AUS MASKENFORMEN

摘要

The method consists in short-time treatment of a block of patterns of wax-like pattern material covered by a refractory shell by blowing onto the block, steam having a temperature of 110-140 DEG C during 5 to 90 seconds. The surface layer of the pattern material melts very quickly and a gap is formed between the pattern and shell. After that this block is treated with hot air. By this all pattern material is heated, melted, and removed from the shell. The steam treatment for a short time permits the use of water soluble binding materials for making the shell, and the initial melting of the pattern surface layer avoids expansion of the unmelted core, exerting stress upon the refractory shell which would cause it to crack.