[Flow of molten metal in denture base in horizontal centrifugal casting procedure. (Part 1) Flow, inflow volume and casting time of molten metal passing through single aprue into disk type mold (author's transl)].
A pyrex glass plate was fitted at the bottom of casting ring, and disk type wax pattern (thickness. 0.43 mm) was put on the plate. Five types of sprueing were applied. Pure tin was casted using holizontal centrifugal casting machine. Flow of molten metal was filmed by the motor drive camera with the method of stroboscope. The results were summarized as follows. 1) When the sprue was attached at the center of the disk type mold vertically, moten metal flowed like a concentric circle at the early stage of casting. It was affected gradually by the direction of gravity and revolution, and it filled the mold from the lower part to the upper part. 2) When the sprue gate was attached to the side edge of the mold, and the sprue gate was placed to the forward and backward direction against the revolution direction, molten metal filled from lower part to the upper part. 3) When the sprue gate was placed against upper edge, molten metal flow was affected by the direction of gravity and revolution. When the sprue gate was placed against lower edge, molten metal filled quietry from the lower part to the upper part. 4) Inflow volume per unit time (inflow rate) was small at the early stage of casting. Inflow rate increased and became constant at the next stage. At the latter stage it became small again. 5) Inflow rate increased with the increase of area of sprue. 6) The time which was necessary to fill the volume of 1 cm (about 80% of the mold volume) became short with the increase of area of sprue. It was also influenced by the type of sprueing.
D003735:Dental Casting Technique / Q000295:instrumentation; D003819:Denture Bases; D010781:Photography; D012212:Rheology; D013997:Time Factors