PCB copper wire off (also often said copper) is bad, PCB factories are said to be laminate problems, requiring its production factory to bear bad losses. The common reasons for PCB factory copper dumping are as follows:
First, PCB factory process factors:
1, copper foil etching is excessive, the electrolytic copper foil used on the market is generally single-sided galvanized (commonly known as ashing foil) and single-sided plated copper (commonly known as reddened foil), the common copper is generally more than 70um galvanized copper foil, reddening foil and 18um below the ashing foil basically have not appeared batch copper.
When the customer line design is better than the etching line, if the copper foil specifications are changed and the etching parameters are not changed, the residence time of the copper foil in the etching solution is too long. Because zinc is originally a active metal, when the copper wire on the PCB is soaked in the etching liquid for a long time, it will lead to excessive side corrosion of the line, causing some fine line backing zinc layer to be completely reacted off and separated from the substrate, that is, the copper wire falls off.
There is also a case that there is no problem with PCB etching parameters, but after etching, washing, and poor drying, resulting in the copper wire is also surrounded by the etching liquid remaining on the PCB surface, which is not treated for a long time, and it will also produce excessive side corrosion of the copper wire and throw copper. This situation is generally concentrated on the fine line, or in the wet weather period, the whole PCB will appear similar bad, strip the copper wire to see its contact surface with the base (the so-called coarser surface) color has changed, and the normal copper foil color is not the same, see the underlying original copper color, thick line copper foil stripping strength is also normal.

2. Local collision occurs in the PCB process, and the copper wire is separated from the substrate by external mechanical force. This poor performance is poor positioning or orientation, the lost copper wire will have obvious distortion, or scratches/impact marks in the same direction. Peel off the bad copper wire to see the copper foil surface, you can see that the color of the copper foil surface is normal, there is no bad side corrosion, and the copper foil peel strength is normal.
3, PCB circuit design is not reasonable, with thick copper foil design too thin line, will also cause excessive line etching and copper.
Second, laminate process reasons:
Under normal circumstances, as long as the hot pressing high temperature section of the laminate exceeds 30 minutes, the copper foil and the semi-cured sheet are basically combined completely, so the pressing generally does not affect the binding force of the copper foil and the substrate in the laminate. However, in the process of laminate stacking and stacking, if PP pollution, or damage to the copper foil wool surface, it will also lead to insufficient bonding force between the copper foil and the substrate after lamination, resulting in positioning (only for the large plate) or sporadic copper wire falling off, but the copper foil stripping strength near the test line will not be abnormal.
Third, laminate raw material reasons:
1, it is mentioned above that ordinary electrolytic copper foil is galvanized or copper-plated products, if the peak value of the wool foil production is abnormal, or galvanized/copper plating, the coating crystal branch is bad, resulting in the peel strength of the copper foil itself is not enough, the bad foil pressing board is made of PCB plug-in in the electronics factory, the copper wire will fall off by external impact. This kind of bad copper stripping copper wire to see the copper foil surface (that is, the contact surface with the substrate) will not be obvious side corrosion, but the peeling strength of the whole copper foil will be very poor.
2, poor adaptability of copper foil and resin: some special properties of laminates now used, such as HTg sheet, because the resin system is not the same, the curing agent used is generally PN resin, resin molecular chain structure is simple, the degree of cross-linking is low when curing, is bound to use special peak copper foil and match. When the copper foil is used in the production of laminate, it does not match the resin system, resulting in insufficient peeling strength of the metal foil covered by sheet metal, and poor copper wire shedding will occur when inserting.