Why Does the Tin Spray on the Circuit Board Cause the Surface of the Pad to Be Uneven

Cause:

1. If the circuit board is unevenly heated up and down, last in, first out, the defects of PCB board bending and warping are likely to occur;

2. When entering the tin furnace, the liquid tin on the pad will be arc-shaped due to the surface tension of the liquid, resulting in uneven thickness of the tin on the pad, and due to the blowing force of the hot air and the effect of gravity, the lower edge of the pad will cause tin sag Solder sag makes the soldering of SMT surface mount parts difficult to stick firmly, and it is easy to cause the offset or tombstone phenomenon of the parts after welding.

3. The smaller the solder-sprayed circuit board pad, the more obvious the arc shape of the pad surface, and the worse the flatness.

Solution:

For BGA package boards with less than 14MIL pads or boards with high flatness requirements, considering the hidden dangers of tin spraying, it is not recommended to make tin sprayed circuit boards. You can change it to gold or gold plating. If customers must make tin spray For the circuit board, the customer’s requirements for flatness must be clarified.

As a professional FPC soft board manufacturer, XPCB Limited is so honored to have worked together with many of you. At XPCB Limited we are always more than ready to assist our new customers in any way we can.  Please feel free to contact us at any time if you have any questions.