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HomePage > Blog > Industry Trends > Aerospace PCB Assembly Basics
Unlike the standard printed circuit boards, the aerospace PCB assembly is different. The boards have to remain faithful in performance even amidst harsh conditions. Despite facing vibrations, fluctuating humidity, and high temperatures, aerospace PCB boards must give unwavering performance.
And so, from choosing material, equipment, and actual assembly process, every step requires keenness. The post thus highlights all you need to know about the aerospace printed circuit board assembly.
The aerospace PCB assembly plays an integral role in the aviation field. Many pieces of equipment and technologies in the industry use PCBs. Some specific applications of PCBs in the aerospace industry are communication systems, satellite technologies, and flight instrumentations.
Others include radar installations, flight power supplies, temperature sensors, and flight instrumentations such as accelerometers and pressure sensors.
Some of the equipment that uses aerospace PCBs
When you compare the standard PCBs to aerospace printed circuit boards, you’ll realize a substantial difference between the two.
The aerospace PCBs feel robust since they use extra durable materials. Further, their manufacturing process uses advanced technologies to make the boards efficient, secure, and safe. In addition, the aerospace fields demand accuracy, precision, and reliability in the harsh environment.
Therefore, the industry requires robust boards that withstand extreme temperature, humidity, and vibration variations. That’s why some aerospace PCB assembly manufacturing companies employ a layer of anodized aluminum on the boards. Doing so protects the oxidation of the board.
The basic components include semiconductor and non-semiconductor devices. Transistors, diodes, capacitors, connectors, and sensors play a vital role. It’s those components that combine to enable the PCBs to find ideal use on control, display, and powerboards of various systems.
Most devices in aviation work for a prolonged period without inspection. Thus, when considering PCB assembly manufacturing for aerospace, you need a board design that can work efficiently for months without breaking down frequently.
And that calls for high-quality components with an extended lifespan. Though that may attract a high initial cost of production, it pays in the long run.
Aerospace printed circuit boards work in an environment that faces extreme pressure, heat, and radiation. As such, when manufacturing the boards and the equipment, you need to take that into account.
Shielding the casing from excessive vibrations and selecting components that withstand high heat and fluctuations in humidity levels is hence a must. Heat level around the engine can sometimes rise to high degrees, from -55 to 175 degrees centigrade. Yet, you must have electronic devices to monitor such changes.
On the other hand, radiation can cause interference with wireless communications. Thus, put in place radiation shielding measures.
The aviation components and devices work with a high level of precision and accuracy. So the components of the board have to be very specific as per the order. Besides, double-check that every part is working and has a wide temperature tolerance.
The aerospace printed circuit boards must maintain high reliability even under demanding situations. Hence, the components must have military grade specification, that is, a tolerance of about 1 to 2 percent.
Interference between the high and low-frequency waveforms may lead to distortion of signals. Therefore, printed aerospace circuit boards must have distinct separation of the high and low-frequency components.
The process for the aerospace PCB assembly differs from the standard process in that it features advanced technologies and requires high precision.
The initial stage is cleaning the PCBs using compressed air and deionized water to prevent corrosion and other defects. Then carry out additional tests to check for any flaws.
After that, use stencil to create desired shapes before applying solder paste evenly on the board. An automated process using robotic machines helps in applying the paste, letting it solidify at the right places and placing the components.
Using a conveyor belt, the board proceeds to the reflow oven. The next stage of the aerospace PCB assembly process is testing the prototype if it adheres to set aviation standards.
For safety purposes, there are set quality standards for every aerospace PCB assembly process. Any manufacturer has to ensure that it meets at least the demands of AS 9100. Further, all other aspects of PCB manufacturing must resonate with the SAE standards.
Even the manufacturing stages, employees involved, and equipment must satisfy Nadcap's set standards. Nadcap preset standards are put in place by leading companies such as Boeing.
There are various factors that you have to consider when selecting components and materials for aerospace PCB assembly projects. Overall, select only components and materials that have high shock absorption ability, durable, and not affected by extreme temperatures.
Copper or aluminum substrates thus usually form the first choice of materials for aerospace boards. Further, using laminates strengthens the boards, thus boosting their durability.
Unlike the standard PCBs, aerospace boards use press-fit components. That way, it limits vibration-related faults from occurring.
Also, the assembly process should match the materials you pick. Remember, in joining the inner and outer layers, you may use buried or blind bias. So, choose your materials and components wisely.
Remember key components such as connectors, sensors, and other semiconductor devices must also be tailored to aviation’s tough demands. That calls for connectors that interlock tightly, pre-tinned wires, and thermal compounds.
The choice of components and materials influences the performance and durability of boards in many ways. For instance, instead of employing forced convection and heavy copper layers to dissipate heat, thin layers of copper graphite materials seem superior in weight and performance. In addition, using an integrated thermal core in multilayered PCB looks promising.
The two technologies help in minimizing widespread aerospace problems of thermal-induced stress on components. Further, emerging miniaturization technology has also helped to reduce the size, weight, and number of PCBs used in aerospace equipment. Cutting down on heat dissipation problem components becomes more durable.
Besides lightness, miniaturization of components and HDI increases a board’s functionality and reliability. Thus, it’s possible to have a multifunctioning board.
Improvement in the manufacturing process using 3-D printing has given birth to more accessible prototyping. By extension, that reduces the manufacturing period and cost. Rapid prototyping that’s more customizable and flexible is a boost to PCB assembly manufacturing for aerospace.
Aerospace PCBs find numerous applications including the following:
Aerospace printed circuit boards find application in flight instruments. That includes flight control panels, cockpit, and navigation displays.
Control panel of an airplane also uses aerospace PCBS
The LED lighting system in an aircraft's exterior or cabin uses aerospace PCBs. The boards assist in controlling lighting patterns, display, and intensity.
Satellite and radio communication systems of aircraft taps on aerospace printed circuit boards. By doing so, the board supports clear signal transmission and stable communication.
The control and distribution of power in the aircraft industry require robust printed circuit boards. Such boards handle high amounts of current and voltages yet realize minimal losses.
The aerospace industry relies on radar technology for monitoring weather, traffic control, and military surveillance. Therefore, aerospace PCBs with high-frequency handling find application in those cases.
The emerging technologies are having an impact on the aerospace field. Every day, the world's craving for sophisticated artificial intelligent devices like surveillance increases. And with the Internet of Things, IoT also expands the need for light, reliable, and accurate devices.
For example, AI has made it possible to have autonomous aircraft and vehicles. More companies are investing in the manufacture of small planes, drones, and flying taxis. Such devices are steadily pushing high the demand for aerospace PCB boards for example, in control and power boards.
At the same time, IoT plus AI has made it possible to have real-time monitoring of vehicles and aircraft. Such real-time monitoring helps in the early detection of problems, routine maintenance, and safety of aircraft. And such devices use aerospace-printed circuit boards.
Military drones
Some of the major challenges facing the aerospace PCB assembly sector include
· Exposure to ionic and Rf radiations in the space which may alter the board's performance.
· Severe mechanical and vibration stress which may displace components from the board
· Extreme temperature levels
· Chemicals in the space oxidizing and corroding copper on the board
· Bureaucratic regulations to adhere to
Some of the possible solutions for the problems facing the industry include
Employing a flex or rigid-flex board with polyamide is a wise idea. Besides lightness, the material fits in small spaces, withstands vibrations, and mechanical shocks. In addition, such a board is resistant to extreme heat and atmospheric chemicals.
Adhering to a copper thickness of about 3 to 4 ounces for every square foot is best for aerospace boards. Such heavy copper conducts heavy currents with ease.
Conformal coatings protect boards from harsh chemicals, extreme heat, and moisture. Thus, it’s best to use hot air solid leveling HASL and then finalize with an acrylic-based spray. Alternatively, you can also choose electroless nickel having gold immersion coating.
Many experts in the aerospace industry advocate sticking to a traceroute angle of less than 45 degrees to get uniform signal transmission. Further shielding clock signals using an aluminum cover is necessary.
Good solderability is necessary for PCBs. Thus, before joining stranded wires to connectors, tin them with molten solder.
When working on a project that’s complex or requires bulk assembly boards, go for an experienced manufacturer with vast knowledge in the industry. Also, for projects with specific demands, settle on a manufacturer that has specialized equipment suitable for the task.
If the supplier had handled such projects in the past, it would be easier for the manufacturer to deliver quality work and tailor your demands to the industry standards. Similarly, letting such a supplier handle your aerospace PCB assembly services lets you enjoy timely and cost-effective work.
Next, consider the approximate cost and duration it takes for the supplier to deliver prototype boards. When approximating the time and cost of producing prototypes, factor in the shipping time and cost too. A good supplier prioritizes fast shipping methods.
Aerospace taps into far-reaching electronics technologies concerning vehicles and pieces of equipment. Thus, standard PCBs that usually fit offices will surely fail if put in the demanding aerospace setting.
That’s why you need to choose a partner that understands the nitty-gritty details of the aerospace PCB assembly process. And that calls for partnering with a supplier that’s AS9100 certified. Such a supplier understands the need for reliability, producing durable products, and taking into account weight and size.
Several space shuttles that have realized great success in their missions show practical uses of aerospace-printed circuit boards. The shuttles such as Discovery, Endeavor, and Atlantis use aerospace PCBS in the control, navigation, and guidance systems. By making over 30 space missions in a couple of years, the s[ce shuttles have shown best practices that use aerospace boards.
The Aerospace PCB assembly process demands keenness and preciseness in choosing components. Thus, when selecting who to partner with for your prototype boards, choose wisely. Settle for a supplier who has been in the field for years, skilled and certified to handle PCB assembly manufacturing for aerospace. You can count on PcBasic as a dependable and qualified partner.