Experiences of design of die casting die for Mg alloy gear box and its die casting method were summarized.The die casting die uses four slide blocks and drawing-core mechanism in three direction

adopting ring structure for main ingate

setting additional ingate inside and smoothly part-separated structure in connection of cavity.Complicated working machine was used to ensure IT6 grade precision for die manufacturing.Rational die casting technology was employed to manufacture Mg alloy gear box including injected pressure for 10～16 MPa

applied specific pressure for 40～70 MPa

filling velocity at 40～60 m/s

die temperature at 220～280 ℃

pouring temperature at 640～690 ℃

filling time for 0.01～0.25

sand holding pressure time for 3～6 s.The practical verification indicated that good die structure and rational die casting method can be helpful to ensure good formation and few defects in die castings

extending the service life of the die.