It talks about the cause and solution of the blackening of the electroplating gold layer. Because the equipment and liquid medicine system used in the production lines of each actual PCB factory are not exactly the same. Therefore, it is necessary to carry out targeted analysis and processing solutions for the product and the actual situation. Here are just three common causes of problems for your reference.
1. Thickness control of the electroplated nickel layer of the circuit board
Everyone must think that the editor is dizzy, and how can the blackening of the electroplated gold layer come to the thickness of the electroplated nickel layer. In fact, the electroplated gold layer of the PCB circuit board is generally very thin, and many of the surface problems reflected in the electroplated gold are caused by the poor performance of the electroplated nickel. Generally, the thinner electroplating nickel layer will cause the appearance of the product to be whitish and black. Therefore, this is the first item to be checked by factory engineers and technicians. Generally, it is necessary to electroplate to a nickel layer thickness of about 5UM to be sufficient.
2. The potion status of the electroplated nickel cylinder
Still want to talk about the nickel cylinder. If the potion of the nickel cylinder is not well maintained for a long time and carbon treatment is not carried out in time, then the electroplated nickel layer will easily produce flaky crystals, and the hardness and brittleness of the coating will increase. Seriously, there will be a problem of black coating. This is the focus of control that many people tend to overlook. It is also often an important cause of problems. Therefore, please carefully check the potion status of your circuit board factory production line for comparative analysis, and conduct thorough carbon treatment in time to restore the activity of the potion and the cleanliness of the electroplating solution. (If there is no carbon treatment, it will be a bigger matter)
3. Control of gold cylinder
Now it comes to the control of the gold vat. Generally, as long as good liquid filtration and replenishment are maintained, the pollution degree and stability of gold tanks will be better than nickel tanks. But you need to pay attention to check whether the following aspects are good:
(1) Is the addition of gold cylinder supplements sufficient and excessive?
(2) How is the PH value control of the PCB processing potion?
(3) What is the condition of the conductive salt? If there is no problem with the inspection result, then use the AA machine to analyze the content of impurities in the solution. The potion status of the margin vat. Finally, don’t forget to check whether the gold cylinder filter cotton core has not been replaced for a long time. If so, it means that your control is not strict. Not too soon to replace.
