Engineers tasked with designing modern electronics face a number of issues. Expectations are for more functionality, more power, and more components in ever-smaller packages but also with quick turnaround for production and staying within tight budget parameters.
Thermal management is a critical aspect of the design process and, as demand for component-density and miniaturization continues to increase, engineers need cooling solutions that fit into small spaces, will not cause project cost overruns, and will provide the best heat transfer possible for today’s modern, processors.
Heat sinks and convection cooling remain the go-to solutions for most systems and high-efficiency Pin Fin heat sinks are designed to meet the requirements of modern electronics cooling with little extra cost added. In particular, the pin fin heat sink geometry is designed to provide increased surface area for heat transfer, low thermal resistance from base to fins at high airflow (200-plus LFM), and work in environments where the direction of airflow is ambiguous.
Pin fin heat sinks from Advanced Thermal Solutions, Inc. (ATS). Pin fin heat sinks provide low thermal resistance at high LFM. (Advanced Thermal Solutions, Inc.)
How does the Pin Fin geometry work?
Barry Dagan, an engineer at Cool Innovations, Inc., wrote a piece for New Electronics in 2009 that explained how the pin fin structure uses the ambient airflow to enhance its thermal performance. [1]
“Any heat sink removes heat by ‘breaking’ the boundary layers of still air that are wrapped around its surface because still air is a very good thermal insulator,” Dagan explained. “The boundary layers are broken by accelerating the flow of air into the heat sink – either using fans and forced airflow or via the chimney effect. In either case, the faster the airstream, the more likely the boundary layers are to break and the more effective the heat sink will be.”
He added, “The round, aerodynamic pin design reduces resistance to surrounding airstreams that enter the pin array, while simultaneously increasing air turbulence. The omnidirectional pin configuration, which allows air to enter and exit the heat sink in any direction, exposes the heat sink to the fastest possible air speed.”
In an earlier article for EE Times, Dagan also noted that the pin fin geometry “allows for a high degree of customization.” Engineers can make adjustments to the overall height, pin height, base thickness, footprint, pin diameter, and pin density to find an optimal cooling solution for their particular project. [2]
“Pin fins can also be catered for situations where both footprint and height are restricted,” Dagan wrote. “For example, the pin fin technology enables the design of heat sinks with a footprint of half an inch squared and a total height as low as 0.15 in.”
A study conducted by Younghwan Joo and Sung Jin Kim that was published in the International Journal of Heat and Mass Transfer indicated that the heat dissipation per mass of optimized pin fin heat sinks was greater than optimized plate-fin heat sinks in most applications. [3]
Pin Fin heat sinks on a PCB. (Advanced Thermal Solutions, Inc.)
In a comparison of heat sinks conducted at Advanced Thermal Solutions, Inc. (ATS) and published in Qpedia Thermal eMagazine, a 33-mm tall elliptical pin fin heat sink under forced convection had the lowest thermal resistance of the 10 heat sinks that were tested. [4]
The ATS family of pin fin heat sinks, made from extruded aluminum, range in sizes from 10 mm by 10 mm to 60 mm by 60 mm. Heights range from 2-25 mm. Through testing in ATS wind tunnels, the pin fin heat sinks demonstrated thermal resistance as low as 2.5°C/W and added little weight to the board. [5]
How are pin fin heat sinks attached to a board?
Pin fin heat sinks are versatile and can be attached to a variety of component packages, including BGA, QFP, LCC, LGA, CLCC, TSOP, DIP, LQFP, and many others. Because pin fin heat sinks are lightweight, standard thermal tape or epoxy can be used to securely attach them to components.
In addition, pin fin heat sinks work with mechanical attachments such as z-clips and ATS maxiGRIPTM or superGRIPTM, which are two-component attachment systems that provide secure hold without damaging the PCB and only minimal addition to the component footprint.
Pin fin heat sinks attached to a PCB with ATS maxiGRIP heat sink attachment system. (Advanced Thermal Solutions, Inc.)
How do pin fin heat sinks provide cost savings?
In his article for EE Times, Dagan explained, “Pin fin technology provides cost-effective heat sink solutions for medium and high-volume applications due to low associated tooling charges and minimal waste of raw materials.” [2]
For example, the ATS family of standard and custom pin fin heat sinks are all available for less than $2.00, with the vast majority of heat sinks available for less than a dollar. This means that engineers can find high-efficiency heat sinks and save money in the budget, which can be put to other design considerations, such as higher-powered fans to increase airflow, better heat sinks attachments, or additional chips and other board components. [5]
This is particularly beneficial for the growing maker market, which is working on new technology or enhancing current technology but generally with far smaller budgets than traditional OEM.
A 2012 article from The Economist, entitled “A Third Industrial Revolution,” discussed the impact of additive manufacturing techniques and how it was now possible to make parts through processes like 3-D printing that are cheaper and faster than traditional methods. According to the article, this will not just affect large manufacturers but also trickles down to a community of makers and smaller companies, what the article labeled “social manufacturing.” [6]
The article added, “As manufacturing goes digital, a third great change is now gathering pace. It will allow things to be made economically in much smaller numbers, more flexibly and with a much lower input of labour, thanks to new materials, completely new processes such as 3D printing, easy-to-use robots and new collaborative manufacturing services available online. The wheel is almost coming full circle, turning away from mass manufacturing and towards much more individualised production.”
Pin fin heat sinks provide cost-effective cooling solutions for small manufacturers and the maker market. (Advanced Thermal Solutions, Inc.)
A study, also from 2012, from MAKE magazine and Intel surveyed the maker community to get data about the (self-proclaimed) hobbyists, builders, tinkerers, and engineers. Out of the total respondents, 79 percent said that they worked in hardware and software, with electronics in second place at more than 60 percent. Thirty-four percent of respondents said that they were involved in making products for income and 19 percent of the total said that they paid for projects with outside funding. [7]
Crowdfunding can only take a project so far and for makers trying to earn money from designs, it is crucial to find cost-effective solutions both to ensure a project comes in under budget and to maximize profits from the sale of the design.
Pin fin heat sinks can be added at low-cost and provide the necessary thermal performance to push a design process along. For the maker market and its (at times) limited resources, high-efficiency pin fin heat sinks provide thermal performance on a budget with the versatility to fit into a variety of systems and designs.
References
[1] http://www.newelectronics.co.uk/electronics-technology/pin-fin-heat-sinks-point-the-way-to-more-efficient-cooling/18641/
[2] http://www.eetimes.com/document.asp?doc_id=1204099
[3] Younghwan Joo and Sung Jin Kim, “Comparison of thermal performance between plate-fin and pin-fin heat sinks in natural convection,” International Journal of Heat and Mass Transfer, April 2015, 345-356.
[4] https://www.qats.com/cms/wp-content/uploads/2014/03/HowAirVelocityAffects_Qpedia08.pdf
[5] https://www.qats.com/News-Room/Press-Releases-Content/1184.aspx
[6] http://www.economist.com/node/21552901
[7] http://www.nyu.edu/social-entrepreneurship/speaker_series/pdf/Maker%20Market%20Study%20FINAL.pdf
For more information about Advanced Thermal Solutions, Inc. (ATS) thermal management consulting and design services, visit www.qats.com or contact ATS at 781.769.2800 or ats-hq@qats.com.
