Low Pressure Casting
process video
1. Preparation of metal smelting and mold or cast
2. Preparation before pouring
Slagging in riser/Measuring level
Crucible sealing/sealing test
Tighten molds or molds, etc
3. Pouring
Lift/Fill/Pressurize
Solidification/Decompression/Cooling
4. Demould
Mold release
Remove casting
Low pressure casting refers to the casting method that the mold is generally placed above a sealed crucible, and compressed air is passed into the crucible to cause a low pressure (0.06~0.15MPa) on the surface of the molten metal, so that the metal liquid rises from the riser to fill the mold and control solidification.
1. This casting method has good feeding capacity and compact casting structure;
2. Easy to cast out large thin wall complex casting;
3. No pollution, no riser;
4. Easy to realize automation;
Step
Low pressure air is introduced into a sealed furnace holding a tank of molten metal.
The metal feeds up slowly through a riser tube and into the die cavity.
Once the casting has solidified in the die, air pressure is released, allowing any residue molten metal still in the riser to fall back into the tank for recycling.
When cooled, the casting is removed.
Features
Low pressure casting equipment
Comparison
| Comparison | Low pressure | High pressure |
| Pressure | Lower, ＜0.08Mpa,Special circumstances can be achieved0.15Mpa | higher, Reach several hundrands Mpa |
| Velocity of metal liquid flow | lesser 150mm/s; The impact on the cavity is small; | Fast,60m/s – 120 m/s; The impact on the cavity is big; |
| Liquid metal flow | Relatively stable | Relative instability |
| Cavity material | Metal type, sand type, can also be other materials cavity | Metal type |
| Mould cavity structure | Suit for more complex cavity castings | Suit for more symply cavity casting |
| Casting size | Small and medium-sized larger-size | Small and medium-sized |
| Air hole | NO | Yes |
| Heat-treatment | Yes | No |
| Material utilization | 85-95% | 50-60% |
