Apparatus for forming a pour hole and main sprue in an investment mold for lost wax casting

摘要

Apparatus for forming a pour hole and main sprue in an investment mold for lost wax casting. A sprue having a flared base, a base member adapted to receive the flared base of the sprue for vertically supporting the sprue, and a flask for containing investment material immersing the sprue, define the casting apparatus of the present invention. The present investment casting sprue apparatus forms a pour hole in the hardened investment material suitable for smoothly introducing liquid metals into the cavity formed by the sprue, thereby reducing the number of casting defects related to turbulent filling. This is accomplished as a result of the flared base of the sprue, which forms a gentle transition into the sprue. The current practice, by contrast, uses a sprue having a cylindrical base which is simply inserted into a hole in a finger or button formed in the supporting base member for the sprue without regard to this smooth transition. The design of the present base member permits ready removal thereof from the hardened investment material without damage to the sprue or to the investment material, thereby reducing the number of inclusion defects in the castings.