Die casting has many processes and stages. In this article, we explain the five major stages of casting from start to finish. Usually, the processes would only take 2 minutes to finish. It is how fast casting is!
1. The Clamping Stage
In this stage, the die is being prepared by clamping its two halves together. The half of a die is cleaned to make it clear of any impurities from the previous injection, and then it is properly lubricated to make the next part of ejection easier. The lubrication processes increases with the part size and so as side cores and number of cavities, so when the dies are bigger, lubrication time will also increase. After lubrication, the two dies are then attached inside the casting machine, are closed and securely clamped together. A strong force is then applied to the dies to cast them properly together while both of them are injected.
In this process, a molten metal in another chamber of the furnace is then injected into the die that are clamped together. The method of how the molten metal is transferred is dependent upon the type of die casting machine being, whether it is the cold chamber of hot chamber machine. Once the molten metal is transferred to the casting machine, it is then injected to the die at a very high temperature. This injection process uses 1,000 to 20,000 psi. This psi pressure holds the molten metal in the dies when it solidifies. It is called “shotting” or the shot when a certain amount of molten metal is injected to the die which takes less than 0.1 second for the solidification process. This injection time is required for the molten metal to wholly fill all the channels and cavities of the die. If a die is needed to be thicker, then longer injection time is also needed.
When the molten metal is injected to the die and enters the die cavity, then the cooling process starts. Then final shape of die casting is then achieved once the molten metal has filled the cavity and cools. In this process, it is necessary that the die is not opened until the molten metal is sure to solidify inside it. There are thermodynamic sensors that will make sure that the metal is cooled to the core; most of the time, the property of metal is used to distinguish how long the die will be left to cool. Furthermore, the thicker the die wall, the longer it requires to be properly cooled.
When the cooling time is done, the die halves can now be opened and the casting is then push out of the die cavity through the process called ejection. A perfect timing is required to open the die which usually takes into consideration the dry cycle time of the machine, and the size of the casting envelope. Once it is opened, a great force is applied to the cast in order to separate the cavity part from the die. You can then see the new metal alloy being casted.
Since the material solidifies, there are still some rough edges and other excesses that need to be trimmed properly in order to get the best shape of the metal. This process smoothens any rough edges of the material.