You might know the fact that one of the crucial factors that affect the lifespan of a light fixture is the thermal design of the LED application. Manufacturers use aluminum die casting to produce different kinds of light fixtures design for LED application. The main trigger points to note during this process are the considerably low price in mass production and the flexibility of the graphic design. Yet, many of us are not aware of the thermal result that manufactures actually get during the process.
Many people wonder why they get a higher die temperature of about 10°C in their final die casted product. However, the explanation to this question is pretty much simple, once you understand the process of die casting.
Die Casting Process and Thermal Conductivity
A hot aluminum metal is subjected to high pressure during the die casting process and it is forced into cavity halves of the mold. Manufacturers foresee the mold from the air vents in order to remove the entrapped air from it before the mold is filled. It is important to note that there will always be a slight portion of air remaining in the metal even after the use of air vent technology. This air remaining in the mold is commonly called micro blowholes.
The second reason for the air to stay in is the formation of gas in the aluminum metal. The gas is actually produced during the heating process of the die casting metal. The entrapped gas and air particles begins to randomly compress in the form of air bubbles of about 5-10 µm.
The formation of these air bubbles happens during the injection cycles and it continues to slightly expand even in the cool down cycle. The amount of gas and air trapped within the molded metal varies according to factors such as the complexity and size of the design. Experts claim that the amount of gas and air can vary from 0.1 to 0.5%.
These numbers might not seem so important initially, but they have the ability to influence the thermal conductivity of the die casting metal. This means that they can cause a major offset in the expected temperature of the die cast light fixtures and their lifetime. Although the process of forging is also capable of creating the perfect thermal results, they considerably limit the shape of the material. So, die casting is the right method of manufacturing light fixtures.