Heat Sink Bonding
Attaching boards to a heat sink is a secondary lamination process that requires special materials and processes. This usually requires the absolute minimum flow possible so that the resin from the prepreg does not ow onto areas where components need to be attached. The metal and the board usually have different expansion rates creating process difficulties to maintain flatness of the final assembly.
Arlon provide a variety of low flow bonding products that may be selected depending on the final property requirements of the finished product. The 47N epoxy product is a common choice for external heat sinks because of it’s very low flow, high adhesion, and capability of lower cure temperatures that can reduce the risk of warpage. The 49N and 51N provide greater thermal resistance and are often the best choice when two boards may be bonded to both sides of a heat sink. The 37N and 38N are polyimide low flow products that match up well with polyimide PWBs.