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THERMAL SIMULATION SOFTWARE Modern electronics thermal simulation – 6SigmaET and other tools

Author / Editor: Nigel Charig / Nicole Kareta

As electronic devices have steadily become more complex, compact, and functional, their designers rely increasingly on thermal simulation tools to avoid costly mistakes and overheating failures at late design stages. This article looks at the popular 6SigmaET software tool, and a couple of others besides.

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6SigmaET - one of the most popular tools currently available - is an electronics thermal modeling tool that uses advanced computational fluid dynamics (CFD) to create accurate models of electronic equipment.
6SigmaET - one of the most popular tools currently available - is an electronics thermal modeling tool that uses advanced computational fluid dynamics (CFD) to create accurate models of electronic equipment.
(Source: ©35microstock -

For as long as engineers have been designing and populating printed circuit boards (PCBs), thermal considerations have been important. Overheating effects are not always immediately observable or predictable, yet a late-stage failure can be extremely expensive in terms of project delay and associated costs. And, as devices have steadily become more complex, compact, and smart, thermal performance has assumed further importance, since excessive heat can lead to higher failure rates. At one time, late-stage failures were inevitable, since they could only reveal themselves during physical testing after a prototype was built. Accordingly, thermal simulation software tools that allow engineers to simulate designs and identify problems before committing to physical prototypes have become available.

One of the most popular tools currently available is 6SigmaET, developed by Future Facilities. 6SigmaET is an electronics thermal modeling tool that uses advanced computational fluid dynamics (CFD) to create accurate models of electronic equipment. Originally introduced in 2009, the tool was designed specifically for the electronics industry. Since then, it has steadily evolved into its current Release 15 implementation. The sectors addressed by 6SigmaET include LEDs, consumer electronics, data center servers and racks, aerospace, automotive and others.

6SigmaET possibilities

Designers can use existing CAD data and PCB design data to create models quickly, create concept models using intelligent modeling objects, identify every component using heat plots, visualize surface temperature of any object and obtain the information they need to make the right decisions. Centralized network libraries allow sharing of objects, assemblies, or entire models across an organization. An object-based gridding feature determines the best grid for a simulation.

6SigmaET can automatically check for collision and modelling errors, allowing designers to address problems as they appear. They can also add electrical boundary conditions to objects, solve for electrical potential, and calculate joule heating values.

Transient simulations can be set up and performed, using a wide range of time-varying properties. Liquid-cooled systems can be modelled using intelligent object such as cold plates, pumps, and cooling ducts. The platform’s solving is cloud based, using a high-performance computer (HPC) cluster. It can be scaled to over 128 cores. Designs and objects can then be consolidated into a singular tree, allowing tighter integration between various models. Designers can build, solve, and analyze their models using a GUI and simple ribbon system; then, fully customizable reporting allows them to communicate, compare and analyze simulation results.

In one application, a customer used 6SigmaET to help with the design, verification, and qualification of a liquid cooled airborne radar processing chassis. This high-powered (3kW power dissipation) and tightly packed chassis had to operate at extreme temperatures (-55 °C to 125 °C) with no cooling mechanism other than the liquid cooling loop. The multi-fluid nature of the model in addition to the liquid-cooled cavities posed significant design challenges. However, the customer was able to accelerate their thermal design by significantly reducing time on model building, meshing (grid generation) and solving. They could also simulate factors such as different altitudes and ambient temperatures using tools built into the software. The cold-plate design was optimized to strike the right balance between pressure drop and heat dissipation by running various designs for the cold plate.

The customer then moved on to understanding the entire system. They modeled the complete chassis, including over 25 high-powered single-board computers (SBCs) and five cold plates in a single model. They were able to ensure that the chassis was properly cooled, that the liquid loop would function correctly and that each of the SBCs would be within its temperature requirements.

6SigmaET evolution

Since its 2009 launch, many new features have been added to 6SigmaET as it has incremented through successive releases. In 2013, for example, Release 8 was launched, introducing intelligent automation and modelling, along with simplified PCB layers and support for importing IDX, XFL and power maps. Then, in 2014, Release 9 included an unstructured solver which improved the platform’s ability to solve complex simulations efficiently and at speed.

Cloud-based computing was added in 2016, allowing engineers to develop and solve complex simulations irrespective of the available hardware. Then, in 2018, Release 12 supported Oculus Rift virtual reality (VR) technology, allowing engineers to physically walk around ‘inside’ their designs, identifying inefficiencies and thermal hotspots from a whole new perspective.

6SigmaET’s current Release 15 has many new features which offer engineers new insights, allow more collaborative work across industry sectors, and facilitate better designs. It provides an enhanced view which helps engineers to analyze models quickly with photorealistic graphics, 60 fps model manipulation and fast-loading surface temperature plots.

Modeling of complex liquid cooled systems has been rendered more efficient, with a fully integrated connection between the 1D flow network and the 3D model. CAD workflow is made faster with an ability to update models to the latest iteration by updating CAD rather than having to rebuild from scratch.

Other automated features relating to both model creation and post processing also save time. Additionally, thermal design can be accelerated with a new reporting functionality: this supports export of images, text and tables in a format that can be opened directly in Microsoft Word and Google Docs.

The company claims that GPU radiation calculations are now 100 times faster, and include ray tracing technology.

Other electronics thermal analysis software tools are available

A wide range of thermal simulation tools are available, but many of these are for other applications, such as architectural design and buildings. Nevertheless, 6SigmaET is not the only tool designed specifically for electronics applications. Other solutions include Siemens’ Simcenter Flotherm, and PICLS from Hexagon.

Simcenter Flotherm comprises electronics cooling simulation software for accurate, fast thermal analysis and supports the development of a thermal digital twin. It provides pre-CAD concept design space exploration, increasing analysis fidelity during development by incorporating ECAD and MCAD data, to final design verification.

Simcenter Flotherm provides thermal simulation at the component, IC package, PCB, and enclosure levels, to large systems including datacenters. Engineers can predict junction temperature, understand airflow, and heat transfer to avoid risks of costly design re-spins.

PICLS generates results in real time through 2D operation. It operates like an ECAD package, using layers and a PCB manipulating tool, and ECAD data can be imported. A free version, called PICLS Lite, is also available. The PICLS packages allow instant thermal analysis at the click of a button.