Effect of Process Parameters on Damage during the Warm Drawing of Magnesium Alloy Shell for Notebook PC

The warm drawing process from magnesium alloy sheet to notebook PC shell reveals specialities due to the low plasticity under low temperature of magnesium alloy. As Cockroft-Lathem ductile damage criteria has been introduced, the damage factors and their distribution were calculated by a series of simulations for the warm drawing process. Then the effect of a series of forming parameters on the maximum damage factor was analyzed and the crack regions were identified as the piece corners. Based on the objective of minimizing the damage factor a set of optimal parameters were achieved: temperature 250 °C, press speed 4mm/s, friction factor 0.09, concave die fillet radius 5.1mm, blank holder force 0.7 MPa, clearance between punch and die 1.15 mm.