Preventing PCB Bending and Warping During Reflow Process

When processing PCBA in a reflow oven, it’s crucial to take measures to prevent board bending and warping. Here are some recommended countermeasures:

1. Minimize Temperature-Induced Stress

Reducing the reflow oven’s temperature or slowing the heating and cooling rates can help minimize stress on the circuit board caused by temperature fluctuations. This approach can effectively reduce the risk of bending and warping, although it may introduce other challenges like solder short circuits.

2. Utilize High Tg PCBs

High Tg PCBs have a higher glass transition temperature, providing better resistance to stress and deformation during the reflow process. While these boards come at a higher cost, they offer enhanced reliability and performance.

3. Increase Board Thickness

Opting for a thicker board, such as 1.6mm, can help prevent bending and deformation, especially for applications where thinness is not a critical factor. Thicker boards provide more stability and reduce the risk of warping.

4. Reduce Board Size and Panels

Minimizing the size of the circuit board and the number of panels can help prevent deformation during reflow. Positioning the board along the edge of the chain and aligning it perpendicular to the furnace direction can reduce the risk of sagging and depression.

5. Use Oven Tray Fixtures

Utilizing oven tray fixtures can support the board against thermal expansion and contraction, maintaining its shape during the cooling process. Adding layers on both upper and lower pallets can further secure the board and reduce deformation in the reflow oven.

6. Opt for Routing Instead of V-Cutting

Avoiding V-Cut techniques or minimizing the cut depth can help preserve the structural integrity of the material between sections, reducing the risk of deformation in the PCB.