LED thermal management is where the use of aluminum castings and aluminum extrusions are most commonly used. During 2012, the lighting industry received thousands of pounds of extrusions from a leading aluminum die casting manufacturer. Flexibility in design, improvements in thermal efficiency, and the advantages in cost of aluminum extrusions over castings were the driving force behind the growth. The fact that aluminum castings are driving designers to discover a solution to a majority of applications is proven by this growth.
The lighting industry uses numerous castings types. Sand castings are used for specialized streetlights and other lower volume applications. Mid-volume applications are made with permanent-mold castings. These include warehouse lighting or standard industrial applications. High-volume applications, including lights that are sold retail are made with die castings.
There is a specified life expectancy for all aluminum cast tooling. When the life expectancy is up, it is time to replace the tooling by the aluminum extrusion die company. A cost advantage exists over castings with aluminum extruders because the replacement cost for the tooling is usually covered in full.
The advantage of using extrusions instead of castings is clear when it comes to the thermal conductivity. There is a higher level of thermal conductivity contained in aluminum extrusions making them up to fifty-three percent more efficient than castings. There is typically a collective conductivity with the range of 120-140W/mk in the castings that are referenced above. The range of conductivity in aluminum extrusions is higher at 200-215-W/mk. The comparative thermal conductivities of cast alloys, extruded alloys and pure aluminum are shown in fig. 2.
Several lighting companies discovered that aluminum extrusions are more efficient than mold, die and sand castings the hard way. The casting process itself for the aluminum die casting manufacturer creates problems with gas porosity. The porosity acts like an oven, keeping the heat in the area when it is near an area where heat is being generated reducing the LED lifespan. The procedures and standards for foreign casters are a lower quality making them a bit problem for them. The process of aluminum extrusion does not create an issue with porosity for the aluminum extrusion die company.