| 摘要 |
<p>The invention aims at providing a process for drying a plaster mold containing a large resin pattern buried therein efficiently without cracking. The invention relates to a drying/pattern melting/burning process for the plaster molds for precision casting which comprises the plaster mold manufacturing step (A) of placing a resin pattern (a) provided with a gate model in a molding flask, pouring a plaster for precision casting into the resulting cavity, and then hardening the plaster, the drying step (B) of separating the molding flask from the hardened plaster mold (P) containing a resin pattern (a) buried therein and then drying the plaster mold (P) under a reduced pressure (I), the pattern-melting step (C) of subjecting the plaster mold (P) to stepwise heating (II) with the sprue (O) down and discharging a liquid component formed by the melting and decomposition of the resin pattern (a) through the sprue (O), and the burning step (D) of burning out the resin pattern (a) and removing excessive water from the plaster. It is preferable that the stepwise heating in the step (C) be conducted at a temperature range of 250˚C or below, while in the step (D), the resin pattern (a) be burned out at 300 to 750˚C.</p> |
