Aavid Thermalloy and IMI-Marston are both major manufacturers of heatsinks. Why on earth would you want to design one? Most people do the thermal calcs for their design and buy a suitable extrusion from one of the manufacturers.
Elsewhere in Eng-Tips I posted a link to Semikron's website. thread238-119812
There are some thermal design notes in there.
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If we learn from our mistakes,
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