By Josh Perry, Editor
A new video from Advanced Thermal Solutions, Inc. (ATS), a leading-edge thermal engineering company based in Norwood, Mass., outlines several of the processes that engineers can use to attach heat pipes to assemblies that remove heat from high-powered devices and electronics systems.
Heat pipes are added to assemblies to dissipate the heat that is being transported from a device. (Advanced Thermal Solutions, Inc.)
ATS engineer Greg Wong explains that heat pipes can be attached to a plate or heat sink. In that case, the heat pipes are transporting heat from a device to the fins of the heat sink where it is dissipated to the ambient. Another solution is to embed heat pipes into the base of a heat sink or plate to spread the heat along the length of the heat sink.
The three attachment methods that Wong explains in the video are mechanical press fit, soldering, and epoxy. According to Wong, mechanical press fit is a quick solution and can produce the right amount of thermal conductivity. In production environments, soldering is the best solution, but it has limitations as well.
“The solder paste is a low-temperature solder paste,” Wong explained. “They're typically based on a tin bismuth alloys with a melt temperature of about 138°C, and that's important for the heat pipes because you really can't bring the heat pipe to more than 250°C or else the water inside the heat pipe will boil and the heat pipe will burst and then it's game over.”
He continued, “And then this whole assembly would go through a re-flow oven. Now this is really important for the soldering process and it's why it is practical in production and maybe not so much for prototypes. Because a re-flow oven will precisely control the temperature of the air inside and it will also have some kind of circulating fan so that the part heats evenly and quickly. And the temperature control in the oven is very important also because you don't want to exceed that critical temperature for the heat pipe.”
In prototypes, Wong suggests epoxy as an easier alternative to soldering. While there may be a slight difference in performance to soldering, epoxy will be within the margin to make it an acceptable solution for pre-production testing.
Watch the video below to learn more about attaching heat pipes to assemblies: