PCBs Accommodate For Bending Fatigue
Printed circuit boards (PCBs) are the heart of modern electronic devices. They connect all the components within a device, and conduct electricity through the copper traces on them. While PCBs are typically rigid, they can also be flexible. These flexible PCBs, known as flex-PCBs, are used in applications such as wearable technology and medical devices. Flexible PCBs can be bent, folded, and twisted to fit into tight spaces or conform to irregular shapes, making them ideal for these types of applications. However, a flexible PCB’s lifespan can be affected by the amount of bending it can withstand before it experiences damage. This is why it is important to design a PCB that can accommodate for bending fatigue.
A pcb board is usually made of a base material, or substrate, that is then coated with a layer of copper. The thickness of this copper coating is what determines a PCB’s flexibility. Thicker copper layers are more rigid, while thinner ones allow for greater flexibility. The substrate can be a hard plastic such as FR4, which is commonly used in high-end electronics, or a less durable material such as epoxies or phenolics, which are more affordable and common in low-end consumer electronics.
After the copper is plated, a solder mask and protective silk-screen are applied to the surface of the pcb board. Once these steps are completed, the component placement begins. These components are either placed by hand or via a pick-and-place machine. The machine uses a camera to identify the reference points on the pcb board and then places the appropriate component on the correct spot. The machine can place a wide variety of components, from large chips to small LEDs.
How Do PCBs Accommodate For Bending Fatigue?
Once all the components are placed, it is time to connect the nets. Using a CAD tool, the copper-to-copper connections are drawn as planes and traces. This process is called routing. It is important that the nets are routed correctly to avoid problems such as signal degradation and excessive noise. This is especially critical for high-speed circuits and signals that need to be transmitted across multiple traces.
To ensure that a PCB can withstand the vibrations of daily use, it is important to perform a vibration fatigue analysis. This analysis will tell you the natural frequency of oscillation of the board, which is determined by its mass and stiffness. It will also give you the maximum vibration peak that can be overcome without causing damage.
By adhering to manufacturer guidelines and industry standards, designers can ensure that their PCBs will withstand the vibrations of everyday life and meet performance requirements. This can be done by ensuring that the pcb has an adequate bending radius, performing a vibration fatigue analysis, and conducting a thermal stress simulation. By doing these things, engineers can eliminate the need for expensive vibration testing on hardware prototypes and improve their PCB’s reliability. Cadence’s suite of design and analysis tools can help them deliver the most reliable layouts for critical applications that need to withstand vibrations.
