Views: 1 Author: Site Editor Publish Time: 2022-08-03 Origin: Site
Extruded metal heat sinks are among the lowest cost, and most widely used heat sinks for electronic thermal management. In addition to being affordable, extrusion heat sinks are lightweight, easily cut to size and shape, and also have excellent heat dissipation.
Material of extrusion heat sinks
Most extrusion heat sinks are made from aluminum alloys, mainly from the 6000 alloy family, where aluminum dominates, so we usually refer to extrusion heat sinks as aluminum extrusion heat sinks. Traces of other elements are added, including magnesium and silicon. These alloys are easy to extrude and machine, weldable, and hardenable.
A standard alloy used for extruded heat sinks is 6063 metal. These can be extruded into complex shapes and have very smooth surfaces. Aluminum 6061 is also used for extrusion. Its tensile strength (up to 240 MPa) is superior to that of the 6063 alloys (up to 186 MPa).
These metals' surfaces can be anodized to replace their naturally occurring aluminum oxide surface layer. Anodizing provides more heat transfer, corrosion resistance, and better adhesion for the primer. It is an electrochemical process that improves surface emissivity, corrosion and wear resistance, and electrical insulation.
Extrusion heat sinks extrusion process.
Aluminum alloys are popular as heat sinks because they offer ductility and formability. They are easy to machine and only one-third as density as steel. This results in both more robust and more stable extrusions at a lower cost than other materials.
The aluminum extrusion process begins with designing and fabricating the die used to shape the radiator profile. After this operation, the cylindrical aluminum billet is heated in a forge to a high temperature, typically between 800-925°F (427-496°C). Next, lubricant is added to the aluminum to prevent it from sticking to any machine. It is then placed on the loader, and pressure is applied with a plunger to push the heated aluminum through the mold.
During this process, nitrogen is added to prevent oxidation. The extruded part will pass through the die to the other side. It will be stretched into the shape of the die opening. Then the finished extrusions are cooled and, if desired, straightened and hardened to obtain the final product.
The aluminum extrusion heat sinks can be cut to the desired length, drilled and machined, and subjected to an aging process. The finished aluminum extrusion heat sinks usually have an anodized surface to improve their thermal performance and a chromate finish to provide corrosion protection.
Extruded radiator profiles
Extruded radiator 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 the addition of a fan or blower. Extrusions can also include unique geometries and groove patterns.
Extrusions are also available in bulk lengths, such as 8 feet, which can be cut to length to suit customer requirements.
Excellent thermal performance
The 6063 aluminum alloy has a thermal conductivity of 201-218 W/(mK). Higher tensile strength 6061 aluminum has a thermal conductivity range of 151-202 W/(mK).
Extruded heat sinks can be designed with very thin and therefore more heat sinks than other heat sinks. They can be extruded with an aspect ratio of approximately 8:1, which can significantly optimize the radiator's performance. The aspect ratio of a heatsink compares the height of its fins and the distance between its fins.
In a typical heatsink, the aspect ratio is between 3:1 and 5:1. High aspect ratio heat sinks have taller fins with less distance between them, and the ratio can be 8:1 to 16:1 or greater.
As a result, high aspect ratio heat sinks provide a greater density of heatsinks for a given footprint than more commonly sized heat sinks. The most significant benefit is its increased thermal surface area due to its additional heatsinks. This equates to more heat sinks in the same space, more heat dissipation area, and therefore better heat dissipation.
Applications of extruded heatsink
Extruded heat sinks can be used in the heat dissipation of semiconductor devices to help them operate at their highest level. Such semiconductor devices include (but are not limited to) RF power transistors, RF power amplifiers, MOSFETs, IGBTs, inverter power modules, and thyristor modules.
In some power conversion circuit applications, large diodes, rectifiers, diode modules, and even high power resistors (thick film, etc.) may also require thermal contact with extruded heat sinks. For cooling DC-DC power converters and power modules, extruded heat sinks are available in full-brick, half-brick, quarter-brick, and one-eighth-brick sizes.
Have you gotten to know more about extruded heat sinks by sharing above? If you want to know more about extrusion heat sinks or other types of heat sinks, you can browse through our product category "Heatsink" to learn more.