Our common computer board basically is epoxy resin glass cloth double PCB circuit board, one side is inserted element for the other side of the welding surface of foot element,
It can be seen that the solder joints are very regular. We call it the PCB plate welding plate for the separation of the solder joints. Why other copper wires do not figure in tin.
Because in addition to the solder pads and the remainder of the surface has a layer of resistance to soldering of the solder mask. Most of the surface resistance welding film is green, and a few are yellow, black, blue, etc.
So in the PCB circuit board industry used to call the solder oil into green. The effect is to prevent the bridging phenomenon during the wave welding, improve the welding quality and save the solder.
It is also a permanent protective layer of PCB board printed board, which can play the role of moisture proof, corrosion prevention, mildew proof and mechanical bruise.
Viewed from outside, the smooth and bright green coating film on the surface is a hot - curing green oil for the photoreceptor of the board.
Not only the appearance of the better looking, it is important that the high accuracy of the welding plate, thus improving the reliability of the solder.
The following several cases for on tin on PCB:
1.PCB circuit board is oxidized and the PCB plate is not tin.
2. The temperature of oven is too low, or too fast, or the tin is not melted.
3. If it’s the problem of solder paste, you can try another type of solder paste.
4. battery chip problem, this is the most common problem, because the battery is generally stainless steel, to electroplating a layer of chromium to tin,
If the plating layer has oil or bad electroplating, it will not go to tin. You can use a soldering iron to see if it can be welded.
Or put some solder paste on the battery sheet, and then heat the battery with a dis-assembly pad or electric heating table to see if the battery can be tin.
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Number of layers
Min. Thickness for inner layers
(Cu thickness are excluded)
Single/Double layer: 0.008±0.004”
4 layer: 0.01±0.008”
8 layer: 0.01±0.008”
Bow and twist
Outer Cu weight
Inner Cu weight
PTH hole tolerance
NPTH hole tolerance
Min hole size
Min solder mask clearanace
Flying Probe Tester
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