How Can Rigid Flex Circuits Survive Harsh Environments?
Rigid Flex Circuits Survive Harsh Environments
A flex circuit is designed to withstand both mechanical stress and the elements. If you were to open up the back of your laptop computer or remove the cover of a cell phone, you would see rigid-flex circuits inside that help make those products work.
Advanced rigid flex circuits are used in a wide variety of electronic devices such as medical imaging equipment, military missile guidance systems and wearable electronics, among many other applications. They have a unique hybrid design that combines the structural integrity of a rigid PCB with flexible areas that can withstand the rigours of harsh environments.
Rigid flex PCBs have plated through holes (PTH) on both sides of the board, connecting the rigid and flexible sections of the circuit. This allows for more components to be incorporated into the device, creating a compact and sophisticated product with improved functionality.
How Can Rigid Flex Circuits Survive Harsh Environments?
These boards are also more reliable than traditional rigid PCBs because the hybrid design reduces the chance of fatigue and cracking in high-shock and vibration conditions. The rigidity of the rigid section helps support the flexing of the circuit, increasing the stability and reliability of the product.
The choice of materials for the rigid and flex sections of a circuit will also affect its performance in harsh environments. FR-4, for example, is a common material used in rigid PCBs but may not perform well in some applications due to its low tensile strength and its lack of resistance to thermal shock. A more robust material, such as a fiberglass reinforced epoxy, is recommended for flex circuits in harsh environments.
Another important factor for rigid flex circuits in harsh environments is their operating temperature range. A flex circuit board’s ability to operate in extreme temperatures is vital, as is its ability to dissipate heat generated by the operation of the devices it is used in.
A good surface finish is also important for rigid-flex circuits in harsh environments. The copper conductor needs a protective layer to protect it from corrosion and other environmental elements. Often, the copper is coated with an insulating dielectric such as polyimide film, which is then laminated onto the baseboard. This coating, along with the etching process that exposes and develops the copper, is crucial for the performance of the circuit.
The surface of a rigid flex circuit is then covered in a material such as soft gold or tin, which prevents the copper from oxidizing and makes it suitable for soldering. This finish is important because it provides a solid, smooth surface for component mounting and soldering. It also adds a cosmetic element to the finished product, enhancing the overall look and feel of the device. Finally, it is important to analyze the reliability of a rigid-flex circuit before mass production begins to ensure that the product will perform as expected under harsh conditions. This can be accomplished through the use of reliability testing that tests for both electrical and physical defects, as well as chemical and thermal stress.