
162 Heat Transfer: Thermal Management of Electronics
can be made from different materials. The drawbacks of this process are high cost
and unidirectional ow in the heat sink.
Another technology with the ability to produce high aspect ratio heat sinks is
folded n heat sink technology shown in Figure 7.23. A continuous thin sheet of n
material is cut to width and folded to a desired n pitch. Then, the n stock is bonded
to a base with thermal epoxy, brazing, or a soldering process. Folded n heat sinks
can be built with ns as thin as 0.25 mm and aspect ratios as high as 50. Also, n
stock and base can be made from different materials. Folded ...