What happened to white spots or white spots in the PCB board?

(1) The sheet is subjected to an improper mechanical external force to cause a white spot resulting from the separation of the local resin and the glass fiber.

(2) Partially bonded material is eroded by fluorine-containing chemicals and etched on the weaving points of the glass fiber cloth to form regular white spots (more severely, it can be seen as square).

(3) Plates that are subjected to improper thermal stress can also cause white spots and white spots.

Solution:

(1) Take measures from the process to minimize or reduce excessive vibration phenomenon of mechanical processing to reduce the effect of mechanical external force.

(2) Especially in the tin-lead alloy plating layer, it is easy to occur between the gold-plated plug blade and the plug blade. Care must be taken to select the appropriate lead-reclaim solution and operation process.

(3) In particular, failure of control such as hot air leveling, infrared heat fusion, etc., will cause thermal stress and cause defects in the substrate.

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