Process Encyclopaedia
Die casting
Other names / variants: ferro-die castingOverview
- Developed in the early 1900s, this is the most common of the casting processes that use a permanent mould.
- It is used for high volume products, of which small zinc die-cast toys (e.g. "Matchbox" cars) are probably the most widely known.
- Very small components like zipper teeth can be made at over 20,000 an hour!
Variants:
Ferro-die is used for high melting point materials such as steels. It uses higher melting point ferrous alloys for the die materials and is more expensive.Materials and shapes
- Mostly used for low melting point alloys such as aluminium, zinc and copper.
In general only small parts are made, but it can be used for components up to 25kg.
- Complex parts can be made with good dimensional accuracy and surface detail.
- A draft (taper) angle has to be incorporated to alloy easy ejection of the part.
- Parts are left with good mechanical surface properties.
- Ejector pin marks are often visible.
Economics
- The machinery is expensive, and can cost well over £100,000.
- Dies cost many thousand pounds and need to be replaced after a few hundred thousand uses. They can take several weeks to manufacture, mean prototype testing is slow.
- The production rate depends on how long the part takes to cool before it can be ejected. This can give rates of 500+ parts per hour in normal conditions.
- Because of the high capital cost, the process is only economic for batches of 100,000+
Typical products
- Small toys e.g. cars/soldiers
- hand tools
- disc drive chassis
- motor casings
- carburettors