Emerging technology, involving diffusion bonding and other techniques new to the market, will increase available alternatives. Lightweight folded fin heat sink offers high density cooling surface area. Folded Fin Folded fins were originally developed for the military and aerospace market to provide large amounts of surface area with very little weight. Bonded, brazed or soldered to heat spreading surfaces, these folded lengths of metal come in many styles and sizes. Manufacturing capability offers fin heights up to 4.0 inches with densities of 8 to 10 fins per inch of width.
Flat fins are the most common style.
Castings Castings are commonly used as low cost heat sinks integrated into enclosures. Due to cost, castings are limited to high volume production programs that use tens of thousands of parts. Castings typically provide near net-shaped parts that require little or no machining prior to assembly. Traditionally, the thermal conductivity of aluminum casting alloys has been significantly lower than extruded alloys. This, coupled with the potential for air pockets and inclusions in some casting styles, can yield poor thermal designs.