Low pressure casting is to place the mold on the closed holding furnace, and the mold cavity is connected with the liquid metal in the furnace through the liquid riser. When working, add pressurized air to the furnace, and the liquid metal will flow into the cavity from the liquid riser. After the liquid metal solidifies, the compressed air in the furnace is released, and the non solidified metal flows back to the furnace from the liquid riser.
In the process of low-pressure casting, the coating should be cleaned before use. After a production cycle, the coating has failed or the surface is uneven, so the coating needs to be polished off with a grinding wheel. Then clean the aluminum chips of the ejector rod and clean the vent plug. Bake the mold at the working temperature of (360 ± 10) ℃, so bake the mold to the working temperature before working.
When the mold is heated to 300 ℃, the coating must be uniform without sagging. The process parameters of low pressure casting are mainly the temperature of molten aluminum, the pressurization rate and pressure setting of equipment. These three factors will affect the quality of castings, resulting in defects such as sand sticking, insufficient pouring and fire choking. Therefore, parameter setting is very important for castings.
Compared with traditional gravity casting, low pressure casting can greatly improve the yield of castings and has high work efficiency. As it crystallizes under pressure, the structure of the casting is dense, and the tensile strength can reach more than 200MPa. However, low-pressure casting has high requirements for equipment, mold and process, and batch waste products will appear if it is careless. Therefore, the above problems need to be paid attention to, and the temperature, exhaust and mold filling parameters need to be well controlled.
Editing: WMM