A circuit board failing to remove heat quickly enough

Why PCB Effective Thermal Conductivity Is Critical for Aerospace Applications

Space is arguably the most hazardous environment for PCBAs and electronic systems. This includes launch and deployment for orbital vehicles such as scale satellites and CubeSats. For interplanetary spacecraft, atmospheric exit and reentry only exacerbate the environmental challenges these systems must endure. Vibration, shock and radiation are among the threats that can affect boards on spacecraft.

Another critical issue for aerospace PCBAs is thermal management. While heat dissipation and distribution are important for all board builds, conducting heat from the board in space due to the near vacuum outside the spacecraft is difficult. And repairing boards that suffered a thermal contingency in space is not an option. Therefore, the stakes for thermal management are even higher, as board failures due to excess heat may render the spacecraft unable to carry out its mission. Your board design must include a means of ensuring PCB effective thermal conductivity.

Why Is PCB Effective Thermal Conductivity Important in Space?

Accomplishments like the reusable Falcon 9 by SpaceX illustrate that the commercialization of space is advancing technologies. However, as resources and technologies continue to expand, the rigors of space travel remain, including the harmful effects of excess heat. Eliminating excess heat begins with PCB effective thermal conductivity, which can be defined as follows:

Definition:

PCB effective thermal conductivity describes the ability of a circuit board to adequately distribute and dissipate excess heat so that no area of the board construction is subject to overheating that could result in component or material damage or degradation that could result in premature failure.

Failing to distribute and dissipate heat effectively can have devastating effects.

Potential Results of Inadequate PCB Effective Thermal Conductivity

☐     Structural degradation

If the board is subject to excessively high temperature that exceeds temperatures at which structural deformation and/or degradation occur for the material, its structural integrity will begin to break down. This can occur when hot spots, which are concentrations of high heat that can form around high-power components, form due to slow dissipation. 

☐     Component damage

All components have thermal limitations or absolute maximum temperatures beyond which the device will no longer function properly and may be physically damaged.

☐     Delamination

For multilayer boards, the PCB lamination process—where the layers of the stackup are pressed into a single structure—is one of the most important steps during fabrication. Once deployed, the structure may suffer substrate degradation, depending on the materials selected, as the temperature exceeds the decomposition temperature.

☐      Fire

Component and board fires can ignite when extreme heat persists for extended periods. Fires can also result from arcing due to overheated insulation material  These catastrophic events not only render the board useless but threaten nearby boards and other elements as well.

To avoid these contingencies, manufacturers must attain PCB effective thermal conductivity when developing aerospace circuit boards.

PCBA Manufacturing for Extreme Environments - Part 1

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Building Aerospace PCBAs for Optimal Thermal Conductivity

In contrast to terrestrially deployed electronic systems, which can typically direct excess heat to the local environment through ventilation, electronic systems aboard spacecraft must dissipate heat within the system or route it for use aboard the vehicle. These kinds of requirements are handled by thermal control systems (TCSs), a necessity aboard spacecraft. For these systems to have the most impact, however, excess heat must be removed from the PCBA, which can be accomplished best by following the guidelines listed below.

Guidelines for Achieving the Best PCB Effective Thermal Conductivity

In many cases, aerospace boards utilize special components and materials such as monolithic microwave integrated circuits (MMICs) and ceramics, which often withstand higher temperatures than other materials. However, the guidelines described above apply to any aerospace board design where optimizing PCB effective thermal conductivity is a paramount objective.

Tempo's Custom Avionics for PCB Manufacturing Service
  • AS9100D and IPC J-STD-001E with Space Addendum certified manufacturing processes.
  • ISO-9001, IPC-600 and IPC-610 commitment to quality certifications.
  • Execute your full development cycle from proto to validation, NPI, and low volume production.
  • Accurate quote in less than a day.
  • DFX support, including DFM, DFA, and DFT from Day 1 of design.
  • Entire turnkey PCB manufacturing in as fast as 4 days.
  • Extreme space environment targeted manufacturing.
  • Use reputable components suppliers to ensure quality, security and traceability.
  • Performs multiple automated inspections during PCB assembly to ensure quality for prototyping.

It is challenging to develop PCBAs for deployment in space, and doing so efficiently requires that you work with a CM experienced in developing aerospace boards. Tempo Automation not only leads the industry with the fastest turnaround time for high-quality, complex PCBA prototyping and low volume production but is also a certified manufacturer with a track record of successfully building boards for some of the aerospace industry’s major manufacturers. We will bring this same level of expertise to bear for your design.

And to help you get started on the best path, we furnish information for your DFM checks and enable you to easily view and download DRC files. If you’re an Altium Designer or Cadence Allegro user, you can simply add these files to your PCB design software. For Mentor Pads or other design packages, we furnish DRC information in other CAD formats and Excel.

If you are ready to have your design manufactured, try our quote tool to upload your CAD and BOM files. If you want more information on how to optimize your PCB effective thermal conductivity, contact us.

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