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In November 2014 Douglas Brooks from UltraCAD Inc. (Kirkland, WA) chose TRM to investigate some thermal issues that attracted him since years. Before that he couldn't find the right tool, precise enough and easy to use, to do it. Meanwhile he became an enthustiastic TRM user and reported about his new experience in many articles and a book.

Now his latest summary is available: "Exiting New Technology: Thermal Risk Maganagament." The PCB Design Magazine (Feb 2017).
Please read from here: Link

Accidentally this week and last week I did some non-standard thermal simulations with through-hole pins by imitating hot solder solder wave underneath the PCB. Of course a mere thermal simualtion can only look at heat spreading in detail but cannot cover metallurgical or fabrication aspects. Nevertheless, the results gave a correct agreement of positions of the problematic pins (and those without problems) compared to the solder wave result. Among other effects it showed that local copper around a solder pin can help heat to flow toward the pin rather than flowing away from it. But all that depends on details of the layout in the bottom layer and maybe in other layers as well, the mass of the component, how the flux is dispensed and many more influencing parameters. A numerical investigation can help to reduce the number of prototypes.

Copper got more expensive. The price  for a ton of copper was jumping from 4800$ to 5800 $ at London Metal Exchange end of october 2016.

Temperature simulations with TRM uncover paths how you can design printed boards more cost effective, tailored to specific environmental conditions and applications. Do you want to pay for surplus copper?

Through the years, the impact of right-angle corners on printed circuit board (PCB) traces has been a hot topic. As early as the 1990s, some were arguing strongly against the use of 90˚ corners, using mitered corners instead. How do TRM simulations and experiments come together?

Read more in our collaboration: Thermal Effects around Right-Angle Trace Corners

In the past I was asked several times about AC on boards and its consequences due to electro-magnetic induction. How does an alternating current change trace heating and how does it influence the traces around? Plenty of approximating formulae on skin and proximity effect for simplified geometries can be found in literature. For traces in boards it is better to solve Maxwell's equations directly.

Over Christmas and New Year there is some time to play with. A test code gives good results for classic test cases. What has to be done now is to define industrial use cases and to solve them.

Call for Action: If you work with AC in printed boards and want to contribute, please leave a message in the comment field below.

Why is temperature of printed boards so important?

Because there are limiting temperatures for operation:

  • Secure maximum operational temperature of components
  • Glass transition temperature of the board material
  • Stability of solder joints

Why should temperature be known as good as possible?

Because too many items depend on temperature:

  • Material properties, e.g. electric resistance of traces and thus voltage feed or impedance for transmission of signals
  • Performance of components
  • Derating of power for hot ambients needs knowledge of component temperature

Why don't simplifying spread sheet calculations work?

Because the local thermal conductivity (the artwork) controls the temperature of a component. It is impossible to include copper patterns, drills and influence from other components in a simple formula, a data sheet or a simple network. Better do a holistic simulation using dedicated software.