Bonded fin heat sinks are an assembly of a grooved base with individual fins bonded into the grooves. This type of heat sink fabrication allows for higher fin densities and fin aspect ratios than what is manufacturable with extrusion methodologies, greatly improving thermal performance as compared to extruded heat sinks due to increased surface area.
Bonded fin types can be constructed in a few ways. Grooved bases can be extruded, die cast, or machined. Machining can allow for additional features like embedded heat pipes, vapor chambers, or encapsulated graphite heat spreaders. Fins are either punched from coil stock or cut from thin plate stock. The fins are inserted into the base grooves and are joined by epoxying, brazing, or soldering.
The epoxy used for bonding is specially formulated to have high thermal conductivity, however brazing offers greater structural integrity and the best thermal performance. Boyd Corporation employs a variety of brazing techniques including CAB, vacuum, and dip brazing. Aluminum must be nickel plated to be soldered.
Boyd's broad portfolio of standard extruded bases and standard cut aluminum fins allows us to quickly design and manufacture semi-custom epoxy bonded fin solutions as well as fully custom heat sinks and systems featuring bonded or brazed fin types.
For rapid thermal modeling and comparison of multiple heat sink constructions please try Aavid Genie our heat sink design tool.