Tony Koryban is one of the most knowledgeable and most humorous thermal engineers in our industry. Happily, many of his unique answers are available for us all to learn from.  From time to time, ATS is delighted to bring you some of his wit and excellent answers to various heat transfer questions.
“Dear Everything-You-Know Guy,
What the heck is wrong with my heat sink? Did I get a bad batch of aluminum or something? A microprocessor on my circuit board is running a little too hot, about 60 degrees C above the inlet air temperature to the box. So I added a heat sink that had about three times the surface area of the microprocessor package. You’re always harping on the idea that heat sinks work by increasing surface area. I expected the temperature rise to go down by 40 degrees, you know, in inverse proportion to the increase in surface area. That would give me a case temperature 20 degrees above the inlet air. OK, maybe not quite that low, being properly pessimistic. But the darn thing only went down 5 degrees! What am I doing wrong? Maybe I need a pin fin heat sink?
Heatsunk in Harrisbur”
So what’s the solution?
Dear Sunk,
Keep working on that pessimism. Only by imagining everything that could possibly go wrong will you ever achieve a true understanding of electronics cooling.
There are lots of reasons why a heat sink doesn’t give you the temperature reduction you think you deserve…..[read more by clicking to Tony’s archives here]