DESIGN, SIMULATION AND FABRICATION OF GRAVITY DIE CASTING MOULD TO ACHIEVE COMPLETE MOULD FILLING

摘要

A previously designed gravity die casting mould based on JIS H5202 standard has failed to achieve complete mould filling in most casting attempts. Therefore, this project attempts to design a new mould to overcome the problem of incomplete mould filling by computational simulation. The gating components like sprue, sprue-well, runners, feeders and ingates are analysed by basic principle of fluid flow to determine their dimensions. The calculated results are used to construct the new mould with solid modelling packages. It is important to seek a better way to design the gating components so that the mould cavities can be filled up homogenously to avoid short mould and cold shut resulting in structural defect in the casting. Improper design and dimensions of the gating components may also lead to the entrapment of aluminium oxide films and gas within the casting. With the aids of computer software like SolidWorks and ProCAST, the mould can be modelled easily and simulation of the casting process can be done to check the flow pattern of molten metal and predict possible defects. Two new designs were proposed and compared. The one with optimized mould filling result was chosen to fabricate the actual mould for experimentation. CNC milling was used to do the fabrication work. Lastly, casting experiments were carried out to confirm the simulation result based on the quality of cast samples.