Toughness in the military cuts across the board. It's not just the tough personnel, but also the electronics and the computers used in the field. Of course, that means that the printed circuit boards (PCBs) used in the defense sector need to be tough as nails.
While designing commercial PCBs is no walk in the park, designing and building military-grade PCBs requires special attention to durability and compliance. All the components have to withstand the demanding environment. Requirements of military-grade electronic PCBs include:
Achieving each of these conditions requires ample preparation and considerations, which start at the design phase.
For a firm understanding of just how critical it is to get military-grade PCBs right, here are a few applications that rely on PCBs in the military:
OEM engineers undertaking military-grade electronics design need to be fully aware of the design considerations critical to reliability and high-quality performance.
All PCBs falling under this category should meet MIL-spec grade standards and pass the highest performance and functionality tests. General considerations for military PCBs include:
After familiarizing yourself with the design requirements, you should also factor in the best PCB substrate types for designing and manufacturing military-grade electronic PCBs.
Only the best quality and heat-resistant materials should be on the table. Military-grade electronics are often used in adverse conditions, including high temperatures. The PCBs should withstand and perform at a high level even in these conditions.
If heat dissipation is necessary, thermal compounds should be used. The finishing materials should also be carefully considered. They should support the PCB to perform in harsh environmental conditions.
High-quality materials that can withstand extreme weather and temperatures are a must. A firm understanding of the different composites, substrates, and elements to use in the PCBs is invaluable at this stage.
They must meet specific rigidity, flexibility, electrical, and thermal requirements to be considered military-grade. Some of the best materials to use for military PCB boards are:
In some cases, anodized aluminum is also used to minimize the effects of heat-induced oxidation.
The military has specific requirements for the surface treatment to protect the PCBs against hostile environmental conditions, including dust, water, vibration, and extreme temperatures. Therefore coating and surface treatments are important features for military-grade electronics. Copper coatings protect PCBs from easily rusting.
Depending on the functionality of the PCB, there are various surface treatment materials available:
Acrylic-based or acid-based sprays can also be used for conformal coating of the PCB to further safeguard them from weather and other external factors.
Durability and reliability are primary concerns for the military. More so because the components are used in less-than-ideal situations and are subject to damage because of solder cracking, among other damages.
On average, military electronics have a lifespan of 5 – 15 years, guaranteeing durability, reliability, and longevity. This calls for minimizing the vibration of a mounted component.
For many military PCBs, through-hole mounting is the recommended method of mounting during PCB assembly. Boards manufactured using this technology are extremely durable. In addition, the method utilizes soldering from the top and bottom of the board, creating strong physical bonds between the components and the board.
Thorough testing is vital to confirm the reliability and durability of the PCB in real-world applications. For military PCBs, the MIL-STD-202 standard is the basis of all testing methods for electronics.
After the PCB meets design for manufacturability considerations, it can be subjected to various tests, including:
Military PCBs can also be subjected to various other tests, including:
MIL-STD, ITAR, NADCAP … It’s easy to get lost in the alphabet soup of military, defense, and aerospace certifications.
Often confused with one another, many OEMs think just one certification will suffice versus all three.
To help you understand the differences and why all three are important, here’s a quick rundown of each standard:
MIL-STD standards cover the end characteristics of the product, as well as the processes, materials, and security standards to be followed in their production. MIL-STD includes five types of defense standards:
These defense standards are meant to ensure the proper performance and logistical usefulness of military equipment.
ITAR standards focus on military equipment and sensitive information that might be involved with military equipment. The number of aspects of product development that are subject to ITAR regulations is substantial -- some obvious and not-so-obvious:
A quality electronics contract manufacturer should verify that ITAR compliance is necessary upfront during the quoting process. That way it can ensure everyone involved in the process is adhering to an ITAR compliance checklist.
Nadcap is an accreditation program for companies in aerospace-related industries. Nadcap accreditation is issued at a company level for specific processes such as:
These standards often work in tandem. Often, some of the technology being produced under MIL-STD compliance will be exported under ITAR regulations. Nadcap accreditation comes into play during construction with heat treatments, coatings, and more.
For MIL-STD grade electronics, ensuring your electronics contract manufacturer has up-to-date MIL-STD, ITAR, and Nadcap certifications will ensure that your PCB is suitable for all military-grade applications and sales.
It’s no secret -- there’s a tangled web of PCB design considerations when it comes to military-grade electronics. Ensure that your ECM is not only fully certified and accredited but also has proven experience producing military-grade components.
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