pcb circuit board handle prolonged exposure to vibration
As the world has moved away from analog to digital electronics, PCBs have become a critical component in devices from smartphones and MP3 players to heart rate monitors and rockets. These circuit boards contain a complex array of small ICs and other components connected by copper wires. The rapid evolution of these circuits has also led to a significant increase in the density of those connections. As a result, these high-density interconnect (HDI) designs have an increased susceptibility to mechanical vibration and electrostatic discharge.
Whether the vibration is caused by an aircraft flight, a rocket launch or just daily use, it can cause damage to components and the printed circuit board. This can result in shortened product life or even complete system failure. To help address these issues, the best way to handle prolonged exposure to vibration is by incorporating design and manufacturing techniques that mitigate these effects.
A pcb circuit board is made up of several layers. These include a rigid base, known as the substrate, which is typically made of fiberglass. This layer is overlaid with a sheet of copper foil and then coated with an insulating material called a dielectric. A solder mask then covers the entire surface of the pcb circuit board except for areas where components are placed. The solder mask is usually green, but it can be any color required by the circuit board design.
How do pcb circuit board handle prolonged exposure to vibration?
The next step is to create a pattern for the circuit on the dielectric. This is done using a process called etching. This process removes the non-conductive parts of the dielectric, leaving behind tracks and pads that take the place of individual points of connection in a traditional point-to-point circuit. The copper tracks are then plated with gold and coated in a passivation chemical. This protects the circuit from corrosion.
Each of these conductive paths is known as a “net” and is represented on the circuit board design with a footprint and a ghost-line image that shows which other components it connects to. Placing these footprints on the PCB while being mindful of their connectivity, areas of excessive heat and noise, and physical obstructions such as connectors, cables and mounting hardware is a skill that requires experience to do well.
As the PCB oscillates, it will flex and stretch the materials in the assembly. This can cause stress on internal connection points such as the hole barrels, which are the metal pins that extend into the holes through which the signals are conducted. This can lead to a broken hole barrel and a loss of connectivity, resulting in intermittent operation at best.
It is possible to improve the performance of a pcb circuit board by making simple layout choices and supply chain priorities. Specifically, by changing the natural frequency of the board or the external excitation frequency, the circuit can avoid resonance conditions that can damage it. Another common issue is that dust and other contaminants can build up on a PCB over time, leading to overheating which can damage the components or lead to system failure.
