The aluminum extrusion process starts with designing and creating the die that will shape the heatsink extrusion. Once this has been done, a cylindrical billet of aluminum is heated up in a forge to high temperatures, generally between 800-925°F (427-496°C). Next, a lubricant is added to the aluminum to prevent it from sticking to any of the machinery. It is then placed on a loader and pressure is applied with a ram to push heated aluminum through the die.
During this process, nitrogen is added in order to prevent oxidation. The extruded part will pass completely through the die and out the other side. It has now been elongated in the shape of the die opening. The finished extrusion is then cooled, and if necessary, a process of straightening and hardening creates the finished product.
They can be cut to the desired lengths, drilled and machined, and undergo a final aging process before being ready for market. [4]
Finished heat sinks typically come with anodized surfaces, which can enhance their thermal performance. Alternatively, a chromate finish provides some corrosion protection, or can be used as a primer before a final paint or powder coating is applied. [5]
Shapes of Extruded Heat Sinks
Extrusions tooling heat sink profiles range from simple flat back fin structures to complex geometries for optimized cooling. They can be used for natural (passive) or forced convection (active) with an added fan or blower. Extruded profiles can also include special geometries and groove patterns for use with clip or push pin attachment systems.
In typical heat sinks the aspect ratio is between 3:1 and 5:1. A high aspect extruded heat sink has taller fins with a smaller distance between them for a ratio that can be 8:1 to 16:1 or greater.
Linear Cellular Alloys (LCAs) are metal honeycombs that are extruded using powder metal-oxide precursors and chemical reactions to obtain near fully dense metallic cell walls. Either ordered periodic or graded cell structures can be formed. In this work, the performance of heat sinks fabricated from stochastic cellular metals is compared to that of LCA heat sinks. Flash diffusivity experiments are performed to determine the in situ thermal properties of cell wall material. The pressure drop for unidirectional fluid flow in the honeycomb channels and the total heat transfer rate of LCA heat sinks are experimentally measured. These measurements are compared to values predicted from a finite difference code and commercial computational fluid dynamics (CFD) software.
What is the purpose of a heat sink?
The purpose of a CPU heatsink is basically the maintenance of the computer. Without a heat sink, the system can overheat and therefore can stop working efficiently. To ensure smooth working of the device it is important to install a heat sink to direct generated heat away from the system and prevent overheating.
Why is a heat sink important?
As stated above, a skived fin heatsink is vital for extending the life of a lighting device. It absorbs unnecessary heat and directs it away from the device. Heat sinks increase the efficiency of the device by removing the excess heat which is why it is an extremely important component. Without a heat sink, computers or other related devices can expire quicker. Heat sinks keep the system cool and provide a good working environment to the other components which heat up quite quickly.
