Under normal circumstances, the quality of PCB circuit boards can be recognized only in appearance. For example, the quality of PCB circuit boards can be identified from the following three aspects:

　　Size and thickness: The thickness of the PCB circuit board is different from that of the standard circuit board. Customers can measure the thickness and standard of their own products.

　　Light and color: The external circuit board is covered with ink, so that the circuit board can play the role of insulation. If the color of the board is not bright and the ink is low, the insulation board itself is not good.

　　 Welding seam: PCB circuit board has many parts. If the welding is not good, the parts are easy to fall off the circuit board, which will seriously affect the welding quality of the circuit board. It is very important to have a good appearance, careful identification, and a strong interface.