What Is Low Pressure Die Casting?
Low-pressure die casting is a method of production that uses pressure – rather than gravity – to fill molds with molten aluminum. Aluminum ingots are added via side chute. The holding furnace (A), located below the wheel cast, is heated until the ingots are liquid. The liquid metal (B) is forced upwards through a riser tube and into the wheel mold cavity (D). The pressure is applied constantly, sometimes in increasing increments (C), to fill the mold and hold the metal in place within the die until it solidifies. Once the cast has solidified, the pressure is released and any residual liquid in the tube or cavity flows back into the holding furnace for “recycling.” When cooled, the cast is simply removed.
Advantages of Low-Pressure Die Casting
Low pressure casting allows precise control during the filling process (B). Injecting the molten metal in this way reduces oxide formation (air pockets) and reduces porosity, ensuring consistency throughout the casting. Low pressure casting results in exceptional density in comparison to other techniques (gravity/high pressure), as well as excellent strength and dimensional accuracy.
The Auto Industry and Beyond
The automotive industry has relied upon low-pressure die casting for decades to create strong, high-quality aluminum casts.
Although low-pressure casting is an exceptional choice for automotive components such as engine blocks, wheels, and suspension parts. Non-automotive industries such as electronics, machine-building, and pipe assemblies also benefit from its lower machining costs, high volume yield, and exceptional metallurgic quality. Cast aluminum’s superior electrical and thermal conductivity make it a very desirable choice for all of these industries.
