If PCB is bent before we use smt pick and place machine ？

What should I do if the PCB board is bent? Cause analysis and improvement method of pcb board warping .today author from qihe smt pick and place machine tell you about it with you .

After the SMT pick and place chip machine processing ,many factories will encounter the phenomenon of bending and rocking of the circuit board during reflow soldering. In severe cases, it may cause bad SMT phenomena such as empty welding of electronic components and tombstones. These phenomena are caused by Because of what? It is because of the uneven pressure on the board or the uneven pressure on the board, which leads to the phenomenon of bending or rocking. When the board passes through the high temperature of reflow soldering, the circuit board will become soft, and the thermal expansion and contraction of the circuit board material. The characteristics of chemical factors have resulted in bent plates and rocker plates.

Solutions and methods for bent plates and rocker plates

Reduce the temperature of reflow soldering or adjust the speed of heating and cooling of the board through reflow soldering, reducing the occurrence of board bending and warping

Plates with higher Tg can withstand higher temperatures and increase the ability to withstand pressure deformation caused by high temperature, relatively speaking, the material cost will increase;

Increase the thickness of the board, which is only suitable for products that do not have PCB thickness requirements for the product itself, and thin products can only use other methods;

Reduce the number of panels and reduce the size of the circuit board, because the larger the panel, the larger the size. After the board is heated at high temperature by reflow soldering, the local pressure is different, and it is easily affected by its own weight. It is easy to cause partial depression and deformation in the middle

Use the oven tray fixture to reduce the deformation of the circuit board. After the circuit board undergoes high temperature thermal expansion and subsequent cooling and contraction after reflow soldering, the tray fixture can stabilize the circuit board. However, the filter tray fixture is more expensive and requires Add labor to place pallet fixtures

you can also choose which smt pick and place machine meets your need . like qihe tvm802 qm61 series .