When we get a PCB, how can we preliminarily judge its quality?
As the saying goes, laymen watch the scene of bustle, while professionals watch the doorways. Here, Xiaobian shares a few details with you. Although these details can’t 100% show that the quality must be very good, if a board factory can control these details in place, it is enough to show their emphasis on quality and rigorous quality management!
One: Look at the ink of PCB board.
1. A good board factory will definitely choose a big brand of ink. At the same time, it pays more attention to the process and baking of printing ink, so that the ink gloss will be better. At the same time, many board factories that have requirements for quality attach great importance to color selection. Perhaps in the eyes of the public, there is only one kind of green ink, but in fact, this green ink can be subdivided into more than 50 kinds. A good board factory selects the best ink after many running-in and experiments.
2. Look at the thickness of the ink. For a good board, the ink thickness must be relatively thick. According to IPC standard, the ink needs to reach 20μ m, but we can’t measure this thickness, but it can be seen by naked eyes. The ink of the board on the left in the picture below can be easily distinguished by the real thing.
Two: Look at the printed words on PCB. We mainly look at the clarity and three-dimensional effect of silk screen printing. Especially for some small font screen printing, high-quality PCB screen printing is very clear, even under a magnifying glass, you still can’t see the rough edges.
The two boards in the picture below are the effect of screen printing magnified 6 times. We can compare them! 1 The picture is clearer and the stereoscopic impression of the font is stronger.
The font of Figure 2 is larger, but the oiling is obviously not full and clear enough.
Third, look at the pad treatment of PCB board.
If it’s a tin spraying plate, we’ll see if the tin spraying is smooth, especially if the IC pin position is neat. If it’s a gold plate, we’ll see if the gold surface is bright, dark yellow or light yellow. The yellower the gold surface, the better the gold deposition process, because it is related to the nickel plating process and the thickness of gold. The following two boards are products made by our company with a thickness of 2U”.
Four: See if BGA pads are full and round.
When a good board factory handles BGA, first of all, engineers will be very careful in optimizing the pads. Secondly, the BGA pads made by good equipment and experienced workers are very well exposed and aligned. Let’s compare the two boards shown below:
Actually, as far as visual recognition is concerned, besides the above four points, there are some other small details that can be identified, such as the smoothness of V-cut, the color of the sheet, the packaging material, and so on. Xiaobian will share more tips with you in the follow-up. I hope you can all purchase high-quality PCB boards!
