During the PCBA processing process, deformation and warping of circuit boards is a common and complex problem. It may be caused by the combined effect of multiple factors. The following is an analysis 

of the causes of deformation and warping of circuit boards by Interli Electronic Technology:

1. Improper selection of raw materials

The lower the Tg value of the material, the easier it is to soften in a high temperature environment, causing the circuit board to deform in high-temperature processes such as reflow soldering.

As electronic products develop towards thinness, the thickness of circuit boards is getting thinner and thinner, reducing their ability to resist deformation. 

The large difference in thermal expansion coefficient between laminates and copper foils can also cause uneven expansion of circuit boards at high temperatures, resulting in warping.

2. Unreasonable design

Uneven distribution of components can cause uneven thermal stress on the circuit board when heated, causing deformation. In a double-sided PCB design, 

if one side of the copper foil is too large (such as a ground wire) and the other side has too little copper foil, it will cause uneven shrinkage on both sides and deformation. 

Connectors and sockets with larger shapes will affect the expansion and contraction of the circuit board, increasing the risk of deformation.

3. Manufacturing process problems

In processes such as reflow soldering and wave soldering, excessively high temperatures or too fast heating and cooling speeds will cause the circuit board to deform due to thermal stress. 

If the clamp is clamped too tightly or the distance between the clamps is too small, the expansion space of the circuit board at high temperature will be limited, resulting in deformation. 

V-Cut is used to split the circuit board, but too deep V-Cut will destroy the board structure and increase the risk of deformation.

4. Temperature difference

During the manufacturing process, if the temperature difference on both sides of the circuit board is large, it will cause uneven expansion, which will cause warping.

5. Multilayer board connection point restrictions

The connection points such as through holes, blind holes, and buried holes in multilayer boards will limit the thermal expansion and contraction effects of the circuit board, resulting in deformation.

In view of the above reasons, the following measures can be taken to reduce the risk of circuit board deformation and warping:

Select high-quality materials: If price and space permit, select PCB materials with high Tg values and appropriately increase the PCB thickness.

Reasonable design: Ensure that components are evenly distributed, the copper foil area on both sides should be balanced, and the copper layer should be filled in the non-circuit area to increase rigidity.

Optimize the process: Control the soldering temperature and lower the temperature of reflow soldering and wave soldering as much as possible. Adjust the fixture or clamping distance to ensure that the 

circuit board has enough expansion space. Pre-bake the PCB before patching to release some stress.

Improve environmental control: Keep the temperature and humidity of the manufacturing environment stable to reduce the impact of temperature differences on the circuit board.

Use auxiliary tools: For large or easily deformed circuit boards, auxiliary tools such as oven trays can be used to reduce the risk of deformation.

Deformation and warping of circuit boards are issues that need to be focused on in PCBA processing. By comprehensively considering multiple factors such as materials, design, process, and environment, 

and taking corresponding solutions, the risk of its occurrence can be effectively reduced.