Low Pressure Die Casting

A metal mould, or die, is mounted on a above a sealed furnace containing molten metal.  A riser tube connects the bottom of the die to the molten metal bath.  The chamber containing the molten metal is pressureised (typically 20-100kPa), and the metal is forced up into the mould.  Once the casting has solidified, the pressure is released and the molten metal falls back into the bath, and the casting ejected in preparation for the next cycle.

At there is only one riser and no feeders, the casting yield is very high.  Clearly, long casting runs are important to justify the cost of the dies.