How to prevent deformation and warpage of circuit board after reflow soldering
Release time：2022-04-11Publisher:Jeenoce
In SMT production process, reflow soldering of circuit board is a necessary process. Sometimes for some reasons, there will be deformation of circuit board after reflow soldering? So how to prevent deformation and warpage of circuit board after reflow soldering? Let's share with you.
1、 Reduce reflow temperature
The temperature of PCB passing through reflow soldering furnace is the main source of stress on PCB. Reducing the temperature or slowing down the reflow soldering temperature rise 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 melting of flux, 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 is, 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 plate can increase its ability to bear stress and deformation, but the price of material is relatively high.
3、 Increase the thickness of circuit board
If the PCB in the SMT production process is not required to be as light and thin as possible, it is best to use a thickness of 1.6mm, so that the risk of bending and deformation can be effectively reduced in the reflow soldering of the circuit board.
4、 Reduce board size and number of panels
In the circuit board SMT production process, most reflow furnaces use chains to transfer PCBs. In this process, PCB with too much weight may be deformed such as depression.
5、 Use reflow soldering furnace tray fixture
The use of 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 fix the circuit board. After the temperature of the circuit board is lower than TG and starts to harden again, it can also maintain the original size.
