Do you know why PCBA circuit board is warped?

PCBA When the plate is reflow welded and wave soldering , Due to various factors PCBA The plate will deform , Which leads to PCBA Poor welding , This has become a headache for production personnel . Next, Gaotuo Electronics will analyze for you PCBA Causes of plate deformation . A brief summary is as follows 6 spot

1、PCBA Plate passing temperature

Every circuit board has the largest TG value , When the temperature of reflow soldering is too high , Higher than the maximum of the circuit board TG When the value of , Naturally, it will cause the board to soften , Cause deformation . Therefore, before production, we must understand the maximum of each circuit board TG value .

2、PCB board

With the popularity of lead-free technology , The temperature of passing through the furnace is higher than that with lead , The requirements for plates are also higher and higher . The lower the TG The more likely the circuit board of the value plate is to deform when passing through the furnace , but TG The higher the value , The more expensive it is .

3、PCBA Plate thickness

With the development of electronic products in the direction of small and thin , The thickness of the circuit board is also becoming thinner , The thinner the circuit board is , During reflow soldering , Affected by high temperature, it is easier to cause deformation of the board .

4、PCBA Board size and number of panels

When the circuit board is reflowed , It is usually placed on the chain for transmission , Chains on both sides serve as support points , The size of the circuit board is too large or the number of panels is too large , It is easy for the circuit board to sag to the middle point , Cause deformation .

5、PCBA The area of copper on the board is uneven

Generally, a large area of copper foil is designed on the circuit board for grounding , occasionally Vcc The layer will also have a large area of copper foil , When these large areas of copper foil cannot be evenly distributed on the same circuit board , It will cause the problem of uneven heat absorption and heat dissipation speed , Of course, circuit boards will also expand and contract , If the expansion and contraction cannot be carried out at the same time, it will cause different stresses and deformation , At this time, if the temperature of the board has reached TG The upper limit of the value , The board will begin to soften , Cause permanent deformation .

6、PCBA Connection points of each layer on the board

Today's circuit boards are mostly multilayer boards , There are many connection points of drilling holes in it , These connection points are divided into through holes 、 Blind hole 、 Buried hole point , These connection points will limit the effect of thermal expansion and cold contraction of the circuit board , This leads to the deformation of the board .

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