Why PCBA boards get deformed?

PCBA board in the reflow and wave soldering, due to the impact of various factors PCBA board will produce deformation, resulting in poor PCBA welding, which has become a headache for production staff. Next, we analyze the reasons for the deformation of the PCBA board.

1, PCBA board over the furnace temperature

Each board will have the maximum TG value, when the reflow temperature is too high, higher than the maximum TG value of the board, will cause the board to soften, causing deformation.

2、PCB board

With the popularity of lead-free process, the temperature of the furnace is higher than leaded, the board is also increasingly demanding. The lower the TG value of the board the board is more likely to be deformed in the furnace, but the higher the TG value, the more expensive.

3, PCBA board thickness

With the development of electronic products in the direction of small and thin, the thickness of the circuit board is also more and more the pursuit of thin, the thinner the thickness of the circuit board, in the reflow soldering, by the impact of high temperature is more likely to lead to the deformation of the board.

4, PCBA board size and the number of board collocation

Circuit board in the reflow soldering, generally placed in the chain for transmission, both sides of the chain as a support point, the size of the circuit board is too large or too many boards, it is easy to board to the center of the point of depression, resulting in deformation.

5, the depth of the V-Cut

V-Cut will destroy the board structure, V-Cut in the original sheet of a large sheet cut out grooves to the V-Cut line is too deep will lead to deformation of the PCBA board.

6, PCBA board laying copper area is uneven

General circuit boards will be designed with a large area of copper foil to be used as a grounding, sometimes Vcc layer will also be designed with a large area of copper foil, when these large-area copper foil can not be evenly distributed on the same circuit board, it will cause heat absorption and heat dissipation rate is not uniform problem, of course, the circuit board will also be thermal expansion and contraction, if the expansion and contraction can not be at the same time will result in a different stress and deformation, the board at this time. If the temperature has reached the upper limit of the TG value, the board will begin to soften, resulting in permanent deformation.

7, the connection points of the layers on the PCBA board

Today's circuit boards are mostly multi-layer boards, there are many drilled connection points, these connection points are divided into through holes, blind holes, buried holes point, these connection points will limit the effect of thermal expansion and contraction of the circuit board, which leads to the deformation of the board. The above are the main reasons for the deformation of the PCBA board, in the PCBA processing and production, you can prevent these reasons, can effectively reduce the deformation of the PCBA board.