2012 NADCA Die Casting Design Competition - Magnesium Die Casting over 0.5 lbs.

Alloy: AZ91

Industry: Homeland Security/Defense

Main Enclosure Casting: The customer desired that internal pins be as cast, rather than a separate piece.

Using an internal lift, TCDC was able to cast internal heat sink pins as part of the casting. The alternate method was to cast a separate piece and fasten it to the casting - which would have added cost and would not have had as good of heat sink properties. The large center opening allowed both a lift and a center gated casting to aid fill on fins and pins. Minimum draft on all features help to keep the weight under design limits.

• Cast a one piece housing with external ribs as heat sinks.
• Center gating allows optimal fill.
• Minimal draft on ribs (1 deg / side), and thin wall design reduces weight.

• Alloy: AZ91D
• Dimensions: 14.9” x 14.6” x 5” H  (396 mm x 370.8 mm x 126.5 mm)
• Weight: 3.05 lbs (1.3 kg)
• Finish: Xylan Coated

Top Plate Casting: Deep internal bosses on the cover with Minimum draft made casting almost equal in surface area between the inside and out. The solution was to apply a double ejector system to both the Ejector half and cover half cavities.

• Alloy: AZ91D
• Dimensions: 14.6” x 14.8” x 2.8” H (370.8 mm x 376 mm x 71.4 mm )
• Weight: 2.92 lbs (1.33 kg)
• Finish: Xylan Coated

Design Properties: The Top Plate required additional ribs to help meet heat sink properties needed. Both the Main Enclosure and Top Plate have limited draft of 1 degree per side on fins as well as thin wall design to minimize weight.

Magnesium Showcase 2012