The process of developing circuit boards consists of three distinct phases: design, build, and test. Although each one consists of different steps or tasks, for optimal PCBA development processes, the phases are integrated to optimize operation, functionality, and quality.
Board quality is primarily determined by the PCBA contract manufacturer (CM) or how the circuit board is built. The quality needed typically aligns with one of the performance class criteria set forth in IPC-6011. The standard defines the reliability, in terms of measurable metrics, for the board build; however, process requirements to ensure standard compliance vary based on the PCBA’s application and operational environment.
Environmental factors that CMs should consider when manufacturing circuit boards include nominal temperature, temperature swing, electromagnetism, and radiation and/or vibration. For industrial PCBAs, the latter is often a primary concern. However, incorporating sound prevention methods can minimize or eliminate the effects of vibration induced fatigue.
Why is Vibration a Problem for PCBAs?
Some electronic circuit boards are designed and manufactured specifically to leverage vibrations, such as piezoelectric transformers. Piezotronics are also commonly employed for testing various aerospace systems; for example, stress and vibration effects of satellites. However, vibration is most often viewed as a problem that must be mitigated, especially for the applications listed below.
Applications where vibration induced fatigue occurs
Aerospace & Defense
Vibration at any stage of flight is typically undesirable for aircraft and space vehicles. And excessive vibration can be an indication of pending structural breakdown.
Similar to flight systems, automotive systems are often subjected to stresses and strains that result in vibration. Obviously, this is unconducive to a comfortable transportation experience. But more importantly, vibration can lead to electronic board failures that degrade performance and/or sacrifice safety.
In today’s factories, automation is used to improve quality, increase production rates, and lower costs. Embedded PCBAs along with robots and cobots are the key drivers of automation for advanced manufacturing facilities. These systems are often in constant or intermittent motion, which subjects the boards to the possibility of vibration induced fatigue.
In addition to normal movements, production equipment and machines can vibrate for other reasons. Root causes may point to loose connections or bolts, physical imbalances, improper alignment, or simple wear and tear. Irrespective of the source, vibration is usually bad for electronic circuit board operation, quality, and reliability.
How to Best Mitigate Vibration Induced Fatigue for Industrial Boards
The elimination of vibration is an environmental issue for the application and system in which the board is installed. A CM, unfortunately, cannot control either. But a robust development process guided by sound design principles, as outlined below, can significantly reduce the potential that your boards will fall victim to vibration induced fatigue.
PCBA Manufacturing for Extreme Environments - Part 2
Suggestions for avoiding PCBA vibration induced fatigue
- Select board materials based on environmental requirements.
The first line of defense against vibration induced fatigue is properly reinforcing the structural integrity of the board materials. Both vibration and motion (constant or intermittent) can weaken the heat-pressed joints of the board stackup or the layers themselves. Moreover, board integrity can be compromised during high-temperature assembly operations such as reflow soldering of surface mount components.
- Minimize manufacturing steps that may weaken structural integrity.
Repetitive steps such as sequential lamentation can weaken board structural integrity. Therefore, strict adherence to cycling limits should be implemented.
- Prioritize solder joint connection quality.
Vibrations can cause components to form solder bridges or completely detach from the board. To minimize this, employ through-hole technology (THT) and ensure your CM follows best practices for SMT solder joint quality.
- Apply good moisture protection techniques.
Moisture is another source that can weaken structural integrity and make your boards more susceptible to vibration induced fatigue. Therefore, utilizing good moisture protection techniques is critical.
- Employ structural testing regimens when necessary.
There are a number of tests that can be performed to determine the structural limits of your boards. These can be costly, especially for destructive physical analysis testing, but having quantitative metrics for your board’s structural limitations can be helpful when selecting materials, picking components, and choosing build parameters to meet operational environmental requirements.
|Tempo's Industry 4.0 Custom PCB Manufacturing Services
Building high-quality PCBAs means constructing boards that meet whatever environmental requirements your design requires. Tempo Automation has demonstrated this capability by building boards for the harsh environment of space, the automobile industry, and industrial facilities.
Tempo employs a white-box turnkey PCBA manufacturing process that promotes collaboration and transparency between engineers and CMs. This allows us to quickly deliver high-quality boards for both standard and non-standard designs that meet industrial and production facility criteria for prototyping and on-demand production. We also provide downloadable DRC files in Altium Designer, Cadence Allegro, Mentor Pads, 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 CAD files or how to incorporate your design into a CAD format, contact us.
 The factory representation is conceptual and only shows the range of operation types that may be included in a smart factory and does not represent any particular industrial facility, its equipment or operations.