E-mail: dongrun@dongruncasting.com

Gravity Die Casting

The History of Gravity Die Casting in Dongrun

In 2000 year, we built our gravity die casting shop in our factory. There was only one gravity casting machine that time. Now we have four lines for gravity casting and can make 3000kg aluminum gravity casting per day. Our production is including auto components, subway components, gas station components, pipeline components, Wheel, fuel injection housings, spline

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What is Gravity Die Casting

Gravity Die Casting is named permanent mold casting or chill casting. Permanent mold is called in America, Chill cast or gravity casting is named in Europe.
The process is suitable for less quantity and high quality aluminum castings,  the surface is better than sand casting. The material of permanent mold is steel, the mold is pre-heated up to 200℃ before the aluminum alloy is poured into the cavity.
Gravity casting means the molten aluminum fill into the cavity of mould by the gravity of aluminum alloy itself, but the gravity casting here is the aluminum gravity casting with metal mould.
The mould of the gravity casting is steel, the common mold material is 45# & H13, we pour the molten aluminum into the cavity which machined by CNC directly and get the raw part, the tooling can use a lot of times and its more efficient than sand casting for no need to make the cavity with sand.

The process is as follows

 1. Make the drawing 

We have to design the drawing which we want to make or get the drawings from our customers, DONGRUN CASTING equipped with UG/SOLIDWORKS/PROC E/CAD to design the drawings for our customers.

2. Make the mold

When finish the drawing, we will design the mould based on the drawings, to decide the casting system, analyze the mould flow, then we machine the the mould according the design, the tooling material is usually 45# & H13 steel

3. Heat the mold and prepare the molten aluminum alloy

When finish the mold, we have to assemble the gravity casting mould on the gravity die casting machine to print the parts, the molten aluminum will solidify very fast and can not fill the cavity well if the mold is not hot enough, so we have to heat the mold to a specified temperature before casting, usually round 300; At the same time, we have to melt the aluminum alloy and degas with nitrogen to control the porosity after casting, the temperature of the aluminum also should be under control

4. Spray the coating to the cavity

The coating can make the cavity surface more smooth, as the result the casting surface will much better, enhance the fire resistance of the tooling and improve the life time of the tooling.
5. Pour the molten aluminum

When the mould is ready, put the core into the cavity if necessary and blow the cavity with air sprayer to guarantee the cavity is clean, put the filter screen on the gate and pour the molten aluminum into the cavity.

6. Get the part

When the aluminum cool down, open the mould and eject out the part, we can repeat casting actions and continue to production.

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