Design of the bottom gating system for the grinding machine body based on large Orifice Discharge Theory

The casting is the body of Y7163-10-102 grinding machine. The material is HT200 and weighs 1300 kg. Its size is 1275 mm in length, 680 mm in width and 620 mm in height. The main thickness is 20 mm with a maximum of 55 mm. The molding is made of resin-hardening sand. In order to produce such a kind of casting, a bottom gating system is employed according to the Large Orifice Discharge Theory. The system is made up of a φ55 mm-diameter sprue, 2 runners and 14 ingates, whose sections are 38 mm x 40 mm and 29 mm x 8 mm respectively. The gating ratio, expressed as Asprue: summation Arunner: summation Aingate, is 1 : 1.2 : 1.4. During the casting process, two φ80 mm-diameter side-risers are set on the top of the casting; the pouring time is 80 s; the rising speed of liquid iron is 8 mm/s in mould cavify. The production result yields an intact casting's shape and a legible contour. No casting defects, such as shrinkages, blowholes, and slag inclusions, are found, and all quality parameters are satisfied.