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Sensible Design: Thermal Management Materials—Golden Rules for Product Selection

Selecting the right type of thermal management method that will suit a particular electronic assembly and its predicted operating conditions is far from easy. There are a number of stages in the selection process that you should consider taking before you decide upon a particular material or material format, whether paste or pad. In this column on achieving effective thermal management of electronic assemblies, I will revisit our trusted question-and-answer format to bring you some essential pointers, beginning with a few cautionary notes on pain points—the occasional pangs of agony you will have to face during the decision-making process.

1. What key pain points are associated with thermal management products?

Well, where do I begin? There are a host of materials and methods out there to choose from, and they serve a variety of purposes depending upon the physical constraints of the application, its environmental considerations, the severity of duty, component layout, assembly geometry, etc.

When choosing an appropriate product, a first question to ask yourself is, “What data can be relied upon?” Certainly, there are some excellent technical data sheets out there that any self-respecting supplier will have taken great care to produce accurately and in good faith. But do you really know what thermal conductivity you will need, for example? And do you know how much material will be needed in the interface between component and heat sink to achieve a thermally stable assembly?

Think about the practicalities and how you intend to apply the material. Will it be manual or automated? And don’t forget those niggling details that tend to get overlooked such as the conditions of the operating environment, which might cause pump-out, for example); migration of the interface material and its effects on the surrounding components or the materials used in the construction of the assembly, which are likely to include sensitive plastics; and special coatings. For guidance on all of this, read on.

2. How do I avoid these pain points?

To answer this and the questions raised in the previous paragraphs, let me give you two golden rules that should at least get you on the right path to making informed choices.

Rule 1

By all means, read through the technical data sheets, but don’t just compare the values on paper. Get some product samples and see how they behave in a real application. A good supplier will be more than happy to accommodate this type of request, and some may even offer in-house test facilities to help you make the right decision. I cannot stress enough the importance of this test-before-you-buy approach. If a thermal management product is not tested before use, the end performance of your product might be very different to what you expected. If you value your reputation in the market, it is vital to ensure that the desired efficiency of heat transfer can be achieved and retained over the expected lifetime of your product.

To read this entire column, which appeared in the February 2019 issue of Design007 Magazine, click here.