| 摘要 |
In a method of preparing a casting mould for precision casting, comprising the steps of preparing a pattern of destructible material on the basis of a master pattern (4), merging the pattern into fine sand of given density, drying the fine sand cover, repeating the merging and drying steps up to reaching a predetermined thickness of the cover, curing and firing the cover and destroying thereby the structure of the pattern, the novelty lies in the steps of preparing the pattern of destructible material as a wax pattern (11) of thin wall, making in the wall of the wax pattern (11) more holes (12) conncecting to each hole (12) a funnel type raising block (5) for determining an inlet passageway (16), merging the wax pattern (11) bearing the fine sand before drying into a fluidised bed containing a mixture comprising grains of corundum of first graininess, repeating the merging step up to reaching the predetermined thickness, arranging in the holes (12) respective locks (15) for connecting layers covering the inner and outer surfaces of the wax pattern, merging at least once the wax pattern (11) into fine sand of higher than given density, and spraying it with a mixture comprising grains of corundum of second, exceeding the first graininess, then melting wax (28) or wax mixture of the wax pattern (11) and firing the body consisted of an outer pattern (17) and inner core (18) maintained together by the locks (15). |
