Design Of Die Casting Die For Magnesium Alloys Telecommunication Parts Through Numerical Simulation

Magnesium alloy is so far the lightest metal, it's series of excellent properties, such as high specific strength, heat conductivity, elastic modular, liquidity, resisting shielding property and electromagnetic interference, make it widely used in automobile, aerospace, electron and communication. What's more, it will take on an extensive prospect.Runner and gating systems play a very important role in the die casting of high quality product. Poor gating system designs can lead to various defects such as gas porosity, shrinkage porosity, flow lines, cold shuts and poor finish. This is particularly so for magnesium alloys, as, due to their specific solidification behaviour, the die cavity is filled at very high gate speeds, which are normally double those commonly used in aluminium die casting. Indeed, the gate speed for a thin-walled magnesium part can be as high as 120 m/s. Optimization of the mold filling patterns through improvement of the runner and gating system design becomes very important. However, the opacity of the metal mould and the high metal pressure during casting make the mould filling process very hard to be directly and visually evaluated. Therefore, numerical simulation has obtained great attention and is considered as the most cost-effective way in optimization of the runner and gating design.In this paper, the property database of magnesium alloys is established firstly. At the same time, two types of gating systems are designed and analyzed by means of Pro/Engineer software. A preliminary design with a common gating system results in swirling filling and a high possibility of air entrapment in the casting. The design is improved by using a continuous double tangential tapered gating system and a bigger size runner. The gate area is increased and the gating speed is slightly reduced. Numerical simulation shows that the new design provides a homogenous mould filling pattern with the last filled areas being located in the places that overflows and vents are conveniently attached. What's more, on the whole, the quality of casting is very good. Based on this optimized runner and gating system, the mould ingredients, including the moving mold cleading, fixed mold cleading, moving mold bed plate, fixed mold bed plate, bolster plate, cushion blocks and the complementary units, are designed. Subsequently, an entire three-dimensional mold assembly diagram is completed in the actual manufacturing order, and all three-dimensional models are converted into two-dimensional engineering drawings. Finally, good quality thin-walled telecommunication prototype parts with a good finish are obtained by means of selective laser sintering technology. From the aspect of structures, the design frame of mould occurs and is justified.