Low Pressure Die Casting
GRAVITY DIE CASTING
LOW PRESSURE DIE CASTING
Low Pressure Die Casting is a sophisticated casting technique wherein low-pressure air is introduced into a sealed furnace containing a reservoir of molten metal. Under controlled pressure—typically between 20 to 100 kN/m²—the molten metal is gently and progressively forced upward through a riser tube into the die cavity. This upward fill ensures minimal turbulence and promotes uniform solidification.
Once the casting has fully solidified within the die, the air pressure is released, allowing any residual molten metal within the riser to return to the holding tank for recycling. Upon cooling, the casting is carefully ejected, ready for finishing or further processing.
Manufacturing Process and Advantages
In this method, metal displacement is achieved through either positive air pressure or vacuum-assisted mould evacuation. A refined variation, known as counter-pressure die casting, utilizes a minimal pressure differential—often less than 1 millibar—achieved through precision-controlled leakage from the mould. This controlled and gradual filling mechanism significantly reduces metal turbulence and establishes favorable thermal gradients, thereby enhancing feeding and producing dense, defect-free castings of exceptional quality.
The dies used in LPDC are typically cooled between cycles using air jets or water sprays, and are coated with specialised die coatings to ensure optimal surface finish and longevity. For components requiring internal geometries, sand or shell cores may be employed within the die. These cores are treated with refractory coatings to withstand the pressure and prevent metal penetration during casting.
A key benefit of low pressure die casting is the absence of traditional runners and feeders, resulting in exceptionally high material yields—often between 80–90%—and minimal remelt requirements. This, coupled with reduced trimming and fettling, translates into significant energy savings and cost efficiency.
M/s. Dhwani Engineering leverages the precision and consistency of Low Pressure Die Casting to manufacture high-integrity components for critical applications. Our commitment to technological excellence ensures that every casting meets the highest standards of quality, efficiency, and sustainability.