How die-cast toy cars are made

Even a vintage hand-lever machine at New Zealand's Fun Ho! could fire over 3000 shots of zinc alloy a day.

stations: 8
things upstream: 71
raw sources: 24
steps from the ground: 10

The short version

Zinc alloy is pumped under pressure into a water-cooled steel die, freezes almost instantly and drops out as a tiny car body. Ejector pins leave small round marks you can still find on the casting. Excess metal is trimmed, the body is polished and spray-painted, and plastic windows, interiors and wheels are fitted around it.

Cut the steel die

A special steel die is cut by CNC machining or spark erosion, with cavities shaped like the product. Separate tubes inside circulate cold water, which controls the die's temperature.
Melt the zinc alloy

Zamak, sold in Britain as Mazac, is melted in a furnace. A slight drop in temperature is enough to freeze it. Its zinc is refined to 99.99 percent purity to avoid zinc pest, a decay caused by impurities.

Goes in
Zinc Aluminum Magnesium Copper
Pump it into the die

The die halves close hydraulically, and molten alloy is pumped into the cavity under pressure. Older machines needed one lever to close the die and another to shoot.
Eject the casting

Circulating water sets the metal almost at once. The die clicks open and ejector pins push the body down a chute, each leaving a small circle where it pressed.
Trim and polish

Excess metal is trimmed off, and the body is sanded and polished until it is smooth and free of defects.
Spray the paint

Base coats, colors and clear finishes go on by airbrush, followed by decals and other small details.

Goes in
Paint
Mold the plastic parts

Windows and tires are usually thermoplastic or rubber rather than metal. They and the interior are made separately from the body.

Goes in
Plastic
Fit wheels and interior

Interior details, windows and wheels on axles are joined to the die-cast body. A final quality check follows.

Goes in
Steel

End of the lineDie-cast toy car

Worth repeating

Hot Wheels went on sale in 1968, to give Mattel a toy line for boys to go with Barbie.
Matchbox cars took their name from small boxes that resembled the ones matches came in.
One small factory in Inglewood, New Zealand, made over 8 million zinc Midget toys between 1965 and 1982.