PCB Technical - What happens if PCB patch processing is poorly plated?

PCB patch processing is now a more popular processing technology in the electronics industry. You can observe that most of the PCB boards are green, because green can bring convenience to processing, so over time the green PCB boards occupy Most of the market. If the PCB board is short-circuited during the processing process, it will cause serious consequences. The poor quality of the PCB board or other operating factors will cause the short-circuit, so how to check whether the PCB board is short-circuited?

1. Vision check

First observe the entire surface of the PCB carefully. If so, please use a magnifying glass or a low-power microscope. Look for tin whiskers between PCB pads or solder joints. Any cracks or spots in the solder should be noted. Check all through holes. If unplated through holes are specified, make sure that this is the case on the board. Poorly plated vias can create shorts between layers and tie everything you have to ground, VCC, or both.

If the short circuit is really serious and causes the component to reach a critical temperature, you will actually see burn spots on the printed circuit board. They may be small, but they will turn brown instead of the normal green solder resist. If you have multiple boards, a burned PCB can help you narrow down a specific location without powering another board, so as not to sacrifice the search range. Unfortunately, our circuit board itself has no burn marks, but a bad luck finger checked whether the integrated circuit is overheated.

Some short circuits will occur inside the circuit board and will not produce burning points. This also means that they will not be noticed from the surface. Here, you will need other methods to detect short circuits in the PCB.

PCB patch

2. Infrared imaging

If it’s not a startup that just started using its hardware budget, you might be lucky to be able to use an infrared camera. Using a thermal imaging camera can help you locate areas that generate a lot of heat. If you do not see the active components far away from the hot spot, then even if the short circuit occurs between the inner layers, a PCB short circuit may occur.

Short circuits usually have higher resistance than ordinary traces or solder joints, because it does not have the benefit of optimization in the design (unless you really want to ignore the rule check). This resistance and the naturally high current due to the direct connection between the power supply and ground means that the conductor in the PCB short circuit will heat up. Start with the lower current you can use. Ideally, a short circuit will be seen first, and then more damage will be caused.

In PCB patch processing, in addition to observing through our eyes as described above, it can actually be tested with some instruments or other methods. It is more common and convenient to use a digital multimeter to test whether it is short-circuited. In this type of processing, the quality of the PCB board is also more important. If the quality of the PCB board is not good enough, it may be easier to produce a short circuit.