Campbellology for Runner System Design

摘要

The runner systems based on the Campbellology, the 10 casting rules of Professor John Campbell, were designed to achieve the bifilm-defect free casts during the filling process in gravity casting. In this study, three main methods were utilized to control the bottom-gating velocity under the critical velocity (the rule no. 2). In these methods, the kinetic energy form of liquid metal (with high velocity) was transformed to the static pressure form (under the critical velocity) in the bottom of the gating systems. The total head height with low energy loss was maintained in these runner designs. A continuous and positive static pressure of liquid metal against to the wall of mold cavity from the bottom to the top of cast was accomplished throughout the filling. Many design schemes to avoid the filling defects, such as oxide entrapment, confluence weld, bubble entrainment, and sand core blow defects, were also suggested in these casting processes.