Why a Die Cast Die?
Die cast die making is the foundation of Model Die & Mold, Inc. More than 50 years ago, our first project was a die cast die.
Similar to plastic injection molding, in die casting, molten metal is forced, under pressure, into a hardened steel mold. This reusable hardened steel mold is called a "die." The word "Die" is actually a misnomer, a holdover from an earlier era before "molding" became more common.
Most die castings are made from non-ferrous metals, usually aluminum or zinc. However, sometimes copper, magnesium, lead, pewter and tin-based alloys are die cast.
Die Casting Today
Die casting can produce geometrically complex metal parts with tight tolerances and smooth surface finishes. Die casting produces more castings than any other casting process. Parts as large as 100 lbs. can be reliably and economically produced with die casting.
Typical die cast parts include:
- Pistons
- Appliance housings
- Pump components
- Engine parts
- Door handles
- Camera frames
- Tablet frames
- Air valves
- Razor handles
- Football cleats
- Hospital bed footboards
- Power tool housings
Depending on the type of metal being cast, a hot- or cold-chamber machine is used.
Cold-Chamber Die Casting
Cold-chamber die casting is used for metals with a high melting point and corrosive properties, like aluminum, brass and magnesium. In cold-chamber casting, the mold is separate from the metal melting pot.
The molten metal is forced into the die chamber under very high pressure with a hydraulic plunger. The pressure is held in the die chamber until the molten metal cools. Cold-chamber die casting has slower cycle times than hot-chamber die casting. The cold-chamber die casting method is best for materials like aluminum, where thicker walls are required for maximum strength.
Hot-Chamber Die Casting
Hot-chamber die casting is used for metal with a lower melting point, like zinc, lead and magnesium. In hot-chamber casting, the die chamber is in the same chamber as the molten metal, resulting in faster cycle times. The molten metal is fed into a chamber via a gooseneck feed. A hydraulic or pneumatic-driven piston then forces the molten metal into the die chamber.
Hot-chamber die casting features:
- Faster cycle times
- More intricate part designs
- Thin-wall applications
- Longer die life expectancy because of lower operating temperatures
Hot-chamber die casting is usually preferred over cold-chamber die casting. Magnesium can be used in both hot-chamber and cold-chamber applications.
Aluminum Die Casting
Aluminum is the most frequently used metal in die casting.
Aluminum features:
- Light weight
- Dimensional stability
- Good stiffness
- Good corrosion resistance
- Good electrical conductivity
- High strength-to-weight
- Excellent thermal conductivity
- Excellent RF and EMI shielding
Zinc Die Casting
Zinc is the second most widely used material in die casting.
Zinc features:
- Versatility
- Thin-wall applications
- Intricate geometries
- Excellent tensile strength
- Excellent RF and EMI shielding
- Wide range of finishing options
- Dimensional stability
- Low cost
- Excellent electrical conductivity
Magnesium Die Casting
Magnesium is the lightest-weight structural alloy.
Magnesium features:
- Ease of machinability
- Good thermal conductivity
- Good electrical conductivity
- Outstanding RF and EMI shielding
- Good finishing characteristics
- Excellent noise and vibration dampening
- High dimensional stability
- Exceptional thin-wall capability
- Excellent for complex geometries