Low Pressure Die Casting

A tool or die is designed and manufactured to the required shape of the component to be made. Molten metal is pushed into the die under low pressure and good surface finish and thin wall thickness are achievable. Once solidified the casting is removed from the die which can be used many times to produce identical parts.

A mould or die, having a horizontal parting line, is mounted on a holding furnace and is connected to the molten metal by a feed tube or stalk. The furnace is pressurised by the introduction of air above the surface of the molten metal causing it to rise steadily in the stalk and quietly fill the mould. The air in the mould cavity is expelled through suitably positioned vents in the die and when the cavity is filled, solidification commences.
Directional solidification, commencing at the extremities and terminating at the sprue, is effected by correct die design and eliminates the need for conventional feeding systems. When the metal has solidified as far back into the sprue as is required, pressure is released in the furnace and the molten metal left in the stalk returns to the holding furnace.

A further short cooling period is allowed to ensure that all sections of the casting are solid, the mould is opened and the casting removed.

Typical applications

• Aluminium automotive parts: wheels, cylinder heads, blocks, manifolds and housings.
• Critical aerospace castings
• Electric motor housings
• Domestic kitchen ware such as pressure cookers