Bending principle of rigid-flex board

When the flexible area of ​​the rigid-flex board is bent, the inner material is subjected to compressive stress and the outer material is subjected to tensile stress. As the degree of bending increases, the stress continues to accumulate. There is a limit to the stress that the material can withstand. Once this limit is exceeded, it will cause material damage. The smaller the bending radius, the greater the stress difference between the inside and outside of the material, and the higher the risk of damage. For example, in wearable devices, rigid-flex boards need to be bent frequently. If the bending radius is not designed reasonably, the copper foil may break in a short time, causing the device to not work properly.