As the demand for personal devices increases, so too does the need for increasingly sophisticated and effective heat sinks, which help to regulate the temperature of electronic devices—keeping them up-and-running and safe. Metal additive manufacturing could offer a viable way forward to improve existing heat sink designs, resulting in more compact and efficient components.
Though new heat sink development is being explored at many levels, a number of university student teams were recently tasked with coming up with their own designs for 3D printed heat sinks. The competition culminated at the 18th Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems and was organized by the America Society of Mechanical Engineers. The competition was also supported and sponsored by General Electric (GE).
The competition recognized teams from five universities—Arizona State University (ASU), Purdue University, the University of Maryland, Trinity College Dublin and Pennsylvania State University—for their proposed 3D printed heat sink designs.
Unlocking new heat sink designs
The competition invited student teams to create new heat sinks—designed specifically for metal AM—within certain constraints. For instance, they all had to work with the same setup, a 70 x 70 mm heat source imitating a computer processor, and were designing within the same dimensions. All of the final designs were also 3D printed by GE AddWorks on a GE Additive Concept Laser M2 machine using aluminum powder. Finally, all the heat sinks were tested under the same conditions at Oregon State University.
The goal of the competition was to come up with the most efficient heat sink by leveraging design for additive manufacturing (DfAM) and the technology’s ability to produce complex geometries.
“There are some features that you cannot make with conventional methods,” explained Faizan Ejaz, a mechanical engineering doctoral student from ASU. “If you want to make a cylindrical honeycomb structure, you cannot manufacture it without requiring other expensive post-processing steps… With the advent of additive manufacturing, now we have access to manufacturing very complex geometries.”
Some surprising results
The ASU team’s heat sink consisted of a design that “swirls” the hot air as it flows through the component, resulting in better air mixing and more turbulence which leads to better heat transfer.
The team from Purdue University, for its part, generated its heat sink design using topology optimization. The design process ultimately led to a heat sink structure that was a surprise to the team and consisted of a gently sloping “L” shape on one side and a protruding “d” shape on the other. According to the team, the “d” causes the air to back up and recirculate slowly before it is channeled out via the L shape.
“We didn’t start with any pre-conceived notion about the shape,” said Serdar Ozguc, a PhD student at Purdue’s Cooling Technologies Research Center (CTRC). “Topology optimization sometimes spits out the craziest things, which are difficult to fabricate using conventional methods. But it was perfect for this contest, because additive manufacturing gives us the freedom to actually build these geometries.”
In addition to showcasing AM’s potential for heat sink production, the competition also gave the university students the unique opportunity to work with industry leaders from GE. The Fortune 500 company offered video conferences to the student teams that made it beyond the first stage of the competition to help in the design stage. The company also 3D printed the five finalists’ heat sinks and tested them.
“The competition helps you to explore your design capabilities and your potential to work in a team,” Ejaz added. “But the best thing about this competition is that you are working directly with GE and they are helping you to become leaders in metal 3D manufacturing.”