How to prevent deformation and warpage of PCB after reflow soldering
Release time：2022-05-30Publisher:Jeenoce
In SMT production process, reflow soldering of circuit board is a necessary process. Sometimes for some reasons, the circuit board will be deformed after reflow soldering? So how to prevent deformation and warpage of PCB after reflow soldering? Let me share with you.
1、 Reduce reflow temperature
The temperature of PCB passing through reflow soldering furnace is the main source of PCB stress. Reducing the temperature or slowing down the reflow soldering temperature and cooling speed can effectively reduce the possibility of plate warping and bending, but this operation may lead to some side effects, such as short circuit of solder or insufficient flux melting, so it needs to be adjusted according to the actual situation.
2、 The circuit board is made of high Tg plate
TG is the glass transition temperature, that is, the temperature at which the material changes from glass state to rubber state. The lower the TG value, the faster the plate starts to soften after entering the reflow furnace, and the longer the time to become soft rubber state will be. Of course, the more serious the deformation of the plate will be. Using higher Tg plates can increase their ability to withstand stress and deformation, but the price of materials is relatively high.
3、 Increase the thickness of the circuit board
If the PCB in SMT production process is not required to be as light and thin as possible, it is better to use a thickness of 1.6mm, so that the risk of bending and deformation can be effectively reduced during reflow soldering of circuit boards.
4、 Reduce board size and number of panels
In the SMT production process of PCB, most reflow soldering furnaces use chains to transfer PCB. In this process, PCB with too much weight may appear deformation such as depression.
5、 Use reflow soldering furnace tray fixture
The used furnace tray for circuit board reflow soldering can reduce the bending and warping of the board. Whether it is thermal expansion or cold contraction, the tray can hold the circuit board until the temperature of the circuit board is lower than the TG value and starts to harden again, and the original size can be maintained.
