Tuesday, 3 November 2015

What is Hot Chamber Die Casting?

One manufacturing technique that revolutionized the industrial world is die casting. Though this technique may sound very simple, it has been effective in reducing production expenses and increasing production count. Die casting is a process in which metal is melted in to its liquid form and then poured into the cast. The design of the cast is created based on the final product design. After the metal is poured into the cast, it is allowed to cool. The liquid metal solidifies into the particular shape. This concept is the basis for zinc alloy die casting and magnesium die casting

There are two types of die casting used in the manufacturing world. One is hot chamber die casting and the other is cold chamber die casting. If you look at the set up for the hot chamber zinc alloy die casting, you will see the following components. It will have a gas/oil accumulator, piston, mold, casting cavity, gooseneck passage, hot chamber and toggle clamp.

First, the molten metal is filled in the cylinder. Next, a plunger forces the liquid metal in the cylinder into the die cavity through the goose neck passage. This passage allows the fluid metal to slowly start cooling. The shape, size and length of this passage will have a direct influence on the outcome of the magnesium die casting. The molten metal in the passage then flows into the cavity. A nozzle is placed at the end of the passage, so a consistent level of pressure is maintained when the liquid metal is poured into the cavity. This pressure is important for the fluid metal to completely spread inside the cavity of the cast. It also allows for uniform distribution of the molten metal. Once the mold is filled, the plunger is brought back to its original position. So, any remaining molten metal flows back into the cylinder. This prevents overfilling of the cast, which could damage the design and the final product.

This metal is allowed to cool, and the cast is broken to remove the finished product. The cooling time depends on whether you are working on zinc alloy die casting or magnesium die casting. The melting points and other properties of the metals are different, and the cast design and process will be modified to suit each type of metal. Careful planning and design will give you consistent results in hot chamber die casting process.

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