Improvements in Zinc Die Casing Using Hot Sprue Technology

摘要

There are several inherent shortcomings in the sprues used in traditional zinc die casting dies. The first metal to pass the cold sprue post, at the slow shot speed, loses considerable process heat before reaching the cavity. This can result in cold flow and random surface defects on the casting. The unavoidable step-down, which occurs at the sprue-nozzle interface and the divergent metal flow around the sprue cone, restricts the flow of the metal and creates excessive turbulence, which can show up as porosity in the casting. A new hot sprue technology has been developed to eliminate these shortcomings and improve the quality and cost of hot chamber zinc die castings. With hot sprue technology, the metal in the sprue remains molten at all times and runs back into the gooseneck after each shot. Metal re-melt is greatly reduced, saving energy, manufacturing costs and greenhouse gas emissions.