Discover a Low Cost Vapor Chamber Heat Sink

Discover a Low Cost Vapor Chamber Heat Sink

Welcome to the launch of our redesigned website and thanks for visiting. As this is our first blog, I thought I’d give you an overview of who we are, what we do and how we came to do it – with a bit more personal flavor than the rest of the site.

The short of it is – Celsia designs and manufactures custom heat sinks using two phase technology: vapor chambers and heat pipes. But the full story, I’m hoping, will prove more informative.

As many of you may know, Celsia has been tackling all sorts of difficult thermal challenges for the last decade. But, our team has been working in this field for much longer. I spent twenty-eight years with Thermacore working stateside and later as chairman of its Taiwanese and Korean operations. The part I enjoyed most was building out the company’s heat pipe / two phase heat transfer manufacturing and optimization facilities. In those days the business was as much about finding new markets as it was about reducing cycle times, increasing yield rates, and experimenting with wick variables.

As heat pipe technology improved cost declined, opening up more opportunities. It didn’t hurt that device enclosures were becoming smaller at the same time that power densities were going through the roof. Heat pipe based thermal modules were a natural fit but they were not without their limitations. These include the following:

  • Heat pipes do a better job transporting heat than they do spreading it around.
  • Most heat pipe configurations require an interface plate, causing increased thermal resistance.
  • Even flatten heat pipes are still 2-3mm thick and often require additional machining.

In the early days another type of two phase heat transfer device, vapor chambers, wasn’t talked about or used much because they were very expensive relative to heat pipes. Here’s a great 4 minute video on heat pipes and vapor chambers from TechQuickie. It’s a bit quirky but informative and fun nonetheless – worth a listen.

All of us that have been in the industry for a while know that vapor chambers were kind of the unwanted step child of the two phase world: thick, heavy and expensive to produce. We experimented with them using the traditional production approach. Namely, a two piece design consisting of upper and lower stamped plates (2 pieces) with a different wick structure for capillary action and numerous internal small columns for support.

Vapor chambers solved the limitations of heat pipes but at a price. Stamping, increased furnace space during sintering, adding individual support columns, and four-sided welding/bonding of the two halves all added time, machinery, and of course cost. That’s why they remained a very niche market for decades. To compound matters, thermal engineers were far less familiar with heat sink design using vapor chambers than they were with heat pipe designs.

Nearly a decade ago Celsia decided to focus its efforts on solving this problem. Create a low cost, high-yield vapor chamber that could be used across broad, price sensitive industries in place of heat pipes. This process required that we not only develop a new type of production process but also that we analyze and perfect heat sink design using this type of liquid two phase device.

To be clear, I’m not arguing that vapor chambers will replace heat pipes only that many space constrained or high heat flux applications are better served by low cost vapor chambers.

After experimenting with literally hundreds of ideas the most effective solution was surprisingly simple, yet devilishly difficult to properly implement. Start with a huge (single piece) unsealed tube, add the wick structure flatten it, ad a micro-thin vapor spacer to provide support, then flatten it some more. No stamping dies or machinery, no individual columns, and no complex diffusion bonding result lower cost and reduced cycle times. An added benefit is that a one piece vapor chamber can be bent into many different configurations (in the Z-direction) post production.

One-piece-vapor-chamber-internal-view

Relatively soon after going to market with this ‘one piece’ vapor chamber design, Celsia was awarded volume production contracts for PC chipsets, high end graphics cards, high performance DRAM memory, and notebook applications. We engineered heat sinks using vapor chambers that could be made as thin as 1mm, be as wide as 100mm, and handle up to 450 w/cm2. Additional contracts in the telecom, networking, power electronics, and defense industries followed.

But, good old two-piece vapor chambers and heat pipes still have a very important role to play in our business. You see our proprietary one piece design isn’t without its limitations. When compared with a two piece design which can be stamped into virtually any shape, Celsia’s one piece version is limited to rectangular shapes. And, heat pipes still maintain a cost advantage for lower power applications and/or those requiring that heat be transported a long distance.

Today, Celsia is fully invested in heat sink design and manufacturing using each type of liquid two phase device. I’ve been doing this for over thirty years now and I make it a point to work with every customer and every inquiry. I love talking about this stuff! Whether you’ve got a huge project with crazy deadlines or just want to chat about thermal options, please write me at gmeyer@celsiainc.com and I’ll be sure to get you on the phone.

Be on the lookout for future Celsia blogs. We plan on discussing technical issues, passing along great articles about new developments in thermal management, and providing design guidelines for heatsinks using two phase devices.

 

Thanks for visiting,

George Meyer