Routing Traces on a Rigid Flex PCB
Rigid-flex circuits offer exceptional flexibility and reliability. They are used in high-quality electronic products like testing equipment, tools, and automobiles that require extensive flexing. However, using rigid-flex technology comes with its challenges due to space constraints and the need for a more complicated PCB design. If you’re not careful, you can make critical DFM mistakes during the design process that can cost you time and money. Learn what they are so that you can avoid them when creating a rigid flex PCB for your next project.
Insufficient clearances and overlapping traces are common rigid flex pcb manufacturers errors that can result in short circuits, fluctuations in impedance, mechanical stresses, and a number of other problems. A rigid-flex pcb manufactuer will need to etch holes through both the rigid and flex sections, so this process can lead to these issues. To mitigate them, designers should use a symmetrical and even material layup with minimum voids and gaps in the rigid section. They should also ensure that traces do not overlap rigid-flex connections or pads, and they should avoid sharp turns and curves in the flex section.
When designing a rigid-flex pcb, you must account for the fact that the flexible portion of the circuit will undergo much more stress than the rigid component. This means that copper traces in the flexing area will experience higher fatigue and can become weak spots. To reduce this risk, designers should ensure that the width of copper tracks stays constant throughout the flexing region and that they don’t change suddenly. In addition, they should keep the margin between the flex and rigid components large to allow for future expansion and contraction.
Key Considerations for Routing Traces on a Rigid Flex PCB
Another issue that designers must be aware of is that plated-through holes are more difficult to plate through rigid-flex materials than conventional rigid boards. As a result, the holes in rigid-flex PCBs must be bigger to accommodate this. This increases the cost of the board and may impact its functionality. To minimize this cost, designers should plan on using a smaller hole size in the rigid area and a larger one in the flex area.
It is important to remember that the flex portions of a rigid-flex PCB are subjected to dynamic bending stresses. This means that the component packages must be rated for flex PCB use and placed in designated rigid sections away from the bending areas of the circuit. Also, the use of stiffeners in the flex areas should be considered to decrease stresses and ensure the stability of the circuit.
Using rigid-flex PCB technology to create complex electronic systems is an exciting endeavor that can deliver significant advantages to your final product. However, it’s crucial to follow a set of DFM rules to avoid costly fabrication and assembly errors. With a knowledgeable rigid-flex PCB fabricator at your side, you can be sure that your resulting device will perform as intended. To get started, contact a reputable rigid-flex PCB manufacturer for more information about their services and capabilities.
