1. The V-Cut on the PCB is generally the main cause of deformation and warping.The V-Cut is to cut out grooves on the original large sheet to obtain a small board, so the V-Cut is prone to deformation;
2. Different PCB will have the maximum heat resistance value. When the reflow temperature is higher than the maximum value. It will cause the board to soften, resulting in deformation and warping.
3. Generally after the SMT patch processing, the PCB will be directly transmitted through the reflow soldering equipment track. If there are overweight parts on the board or the size of the board is too large, and the reflow temperature is high, it will show the phenomenon of depression in the middle due to its own weight and heat, resulting in bending deformation.
4. Electronic products are becoming smaller and lighter , also the thickness of PCB is getting thinner and thinner. The thinner the board, the easier it is to deform at high temperatures.
5. Generally, a large area of copper foil is designed on the PCB for grounding. When these copper foil cannot be evenly distributed on the same PCB, it will cause the problem of uneven heat absorption and heat dissipation speed, and warpage will also occur after cooling;
6. Since many PCB materials are not in original packaging, due to the environmental problems of storage, there will be more or less moisture in the PCB. If the baking operation is not carried out before the SMT processing , when the reflow soldering has a high temperature, the water will evaporate, which will cause deformation and warping.