Gravity casting is also called permanent mold casting. The mold is made from iron, steel, resin sand. The mold is installed on a sealed furnace containing molten metal. Its pouring system consists of a riser tube connects the bottom of the mold to the molten metal bath. 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. The pressure can be controlled and adjusted against the structure, weight and material of the casting.
How does the gravity casting process work?
Gravity casting was one of the very earliest processes to be invented for metal and light alloy die casting. In this process which can be fully automated, the molten metal is poured directly from a ladle into a semi-permanent or permanent die.
The goal is to fill the die with minimum turbulence through one or more channels to reduce oxidation and foaming. This minimises porosity and inclusions, giving optimum metal characteristics in the final casting.
Gravity casting equipment can have a vertical or horizontal mould opening, or tilting technology with 0/90 ° or 0/120 ° tilting provides an alternative. With tilting die-casting, the metal flow at the die inlet is controlled by the tilting angle and speed of the die.
Gravity casting technology’s main advantages include:
1. Suitability for high-volume, automated production 2. Minimum investment required for small and medium volume production 3. Produces parts with excellent mechanical properties that are also suitable for heat treatment 4. As sand cores can be placed within the mould, gravity die casting can also produce parts with complex shapes.
Gravity die casting technology is ideal for diverse complex aluminium casting production of automotive parts such as: turbos, brake calipers, knuckles, engine cylinder heads, engine blocks and pistons. It suits many other industries too, from lighting components to kitchen tools.