Influence of casting process parameters on surface roughness in hot-chamber die casting of AZ91D

摘要

Cast magnesium AZ91D, used for cases, covers and housings, for consumer electronics faces increased requirements on aesthetically pleasing surfaces. The casting conditions have strong effect on as-cast surface roughness for thin-walled castings. This is currently not well understood. In the current study surface roughness was measured parallel and perpendicular to the filling direction and on both sides on straight flat thin specimen. The parameters studied were First and Second phase injection speed, Cooling time, and Melt temperature. The Fix and Moving side die temperatures were varied, with the fix side was kept hotter. A D-Optimal experimental design was used resulting in 31 different settings. The results showed that roughness was decreased by minimizing the temperature difference between the two die halves, increasing cooling time and first phase injection speed. Increasing the second phase injection speed increased roughness.