Flexure Limitation
The minimum curvature allowable for a circuit board during handling or assembly determines the mechanical strain limits of the substrate and components. Choosing the correct pcb bend radius is essential to prevent copper trace fracturing, solder joint fatigue, or multilayer delamination in both rigid-flex and thin rigid boards. This parameter is dictated by the copper foil thickness, the resin system, and the total layer count.
Calculations are performed to ensure the board is never bent beyond its plastic deformation point.
Installation Calculation
For dynamic flex applications, the assembly must withstand millions of bending cycles without electrical degradation. The pcb bend radius calculation uses the overall thickness of the flexible section and a multiplier based on the layer count and use case. Single-sided flexible circuits can tolerate a smaller radius than double-sided or multi-layer boards because the neutral axis sits closer to the conductive layer.
Specifying a generous radius during design ensures the longevity of the copper traces under cyclic stress.
Inspection Protocol
Verifying compliance involves measuring the actual curvature using mechanical fixtures or digital imaging. A non-compliant pcb bend radius is identified during structural flexure verification, where boards are subjected to controlled bending. This ensures the physical limit is not exceeded.
