common issues with flex PCB suppliers
PCBs provide a critical function in a variety of electronic devices and applications. But, the design process is not without its challenges, and there are some issues that can occur during prototyping that should be addressed before a part is brought into production. These issues, if left unaddressed, can have a significant impact on your device’s functionality and overall reliability.
Flex circuit board technology offers a number of benefits that are attractive to a wide range of electronic applications, including cost savings and space efficiency. However, the use of a flex pcb supplier can also bring several mechanical issues that require careful consideration and planning to overcome.
These issues can be caused by poor PCB layout, design, and fabrication processes. To ensure a robust design that can meet your device’s performance and functionality requirements, it is important to work with an experienced and trusted flex pcb supplier. To help you avoid common pitfalls, here are some questions to ask your flex PCB supplier:
What are common issues with flex PCB suppliers?
Mismatched CTE expansion rates between the rigid and flex sections of the board. This can lead to traces becoming damaged by stress cracking at the bend point. This can be avoided by designing the flex section with a solid region of copper and by using a cross-hatched ground plane on the flex section. Using a mirrored ground plane can also help minimize stress cracking, but this will increase manufacturing costs and may cause the rigid and flex portions of the PCB to stretch at different rates.
Excessively Tight Tolerances: Flex manufacturers have a range of tolerance capabilities across a variety of dimensions and it is very easy for a design to over-tolerate the capabilities of the manufacturer. For example, tight bends can result in a solder joint cracking at the bending point. Also, a hole pattern that is too dense will inhibit flexing and should be modified to allow for the required flexibility. Lastly, unrelated “boilerplate” notes should be avoided as these can add confusion and delay at quoting, setup, and first article inspection.
Rigid-flex PCBs are commonly used in consumer electronics and medical equipment due to their compact size and ability to conform to the shape of the device. They are also employed in aerospace and automotive equipment for their weight-saving capabilities. In addition, the reduced interconnects and solder joints on a flex circuit board improve its reliability by minimizing points of failure.
But, the flexible nature of a flex circuit can pose a challenge in the prototyping stage when parts are installed and removed multiple times to evaluate form, fit, and function. During this phase, it is very easy for the flexible circuit to be inadvertently mishandled or even dropped. Fortunately, most folded designs have a safety mechanism of a section of pressure sensitive adhesive (PSA) in the fold area to prevent the flex from being opened and re-installed. This can cause some fallout during prototyping, but will not present any problems when the flex is installed in the final product by a trained technician following a documented procedure.
