REMOVAL OF BAR-SHAPED WASTE BRIDGE OF CASTING

摘要

PURPOSE:To break a bar-shaped waste bridge simultaneously with sand stripping of a casting by the oscillation of an exciter by casting the casting provided with annular grooves having a V-shaped section on the outside periphery at both ends of said bridge. CONSTITUTION:Tensile or compressive stress arises in the bar-shaped waste bridge 1 according to the thermal stress arising from a difference in the solidifying rate in each part of the casting. The casting 3 taken out of a casting mold is therefore attached to the conventional type exciter for sand stripping having a relatively low oscillation frequency and the oscillation in the direction approximately perpendicular to the axial line of the bridge 1 is applied to the casting 3. The tensile or compressive stress and the stress generated by the oscillation of the bridge 1 are thereupon concentrated to the recesses on the V-shaped annular grooves 2 provided to the bridge 1. The bridge 1 is therefore broken from the casting 3 in the base of the grooves 2 by the fatigue of the casting metal.