Gravity die casting is called permanent mold casting or cold casting. Gravity casting molds are called permanent molds in the United States and cold casting or gravity casting in Europe.
This process is suitable for small quantity and high quality aluminum castings, the surface is better than sand casting. The material of the permanent mold is steel, and before pouring the aluminum alloy into the cavity, the mold is preheated to 200 degrees Celsius.
Gravity casting means that the molten aluminum is filled into the mold cavity by the gravity of the aluminum alloy itself, but the gravity casting here is the aluminum gravity casting of the metal mold.
The gravity casting mold is steel, and the common mold material is 45amp; H13. The aluminum liquid is directly poured into the CNC machined cavity to obtain the blank. The mold can be used multiple times, and the efficiency is higher. Compared with sand casting, no need to use sand to make the cavity .
The process is as follows
1. Drawing
We have to design the drawings we want to make or get drawings from customers, Dongrun Casting is equipped with UG\/SOLIDWORKS\/PROC E\/CAD to design drawings for our customers.
2. Make the mold
After the drawing is completed, design the mold according to the drawing, determine the pouring system, analyze the mold process, and then process the mold according to the design, the mold material is usually 45amp; H13 steel
3. Heat the mold and prepare to melt the aluminum alloy
After finishing the mold, we have to assemble the gravity casting mold on the gravity die casting machine to print the part, if the mold is not hot enough, the aluminum liquid will solidify quickly and cannot fill the cavity well, so we have to heat the mold to the specified temperature before pouring, It is generally around 300 degrees Celsius; at the same time, we must melt the aluminum alloy after casting and degas it with nitrogen to control the porosity, and the temperature of the aluminum should also be controlled
4. Spray paint into cavity
The coating can make the surface of the cavity smoother, so as to make the surface of the casting better, enhance the fire resistance of the mold, and improve the service life of the mold.
5. Pour in the molten aluminum
After the mold is ready, put the core into the cavity if necessary, and blow the cavity with an air sprayer to keep the cavity clean, put the filter screen on the gate, and pour the molten aluminum into the cavity.
6. Get the parts
When the aluminum is cooled, open the mold and eject the part, we can repeat the casting action and continue production.