Which process is involved in PCB coating separation?

Which process is involved in PCB coating separation?

The separation of plating layer must be caused by poor adhesion between electroplating metal and substrate. How to find out the cause of poor adhesion is the focus of your problem. To solve this problem, we can simplify the problem into two types: poor adhesion caused by foreign matters and poor adhesion without foreign matters. It is not easy to obtain good electroplating results if there are foreign matters left in the electroplating area, such as heavy oxide layer, poor degreasing treatment, poor micro etching treatment, insufficient water washing, etc. In the process of circuit board production, production is often suspended due to specific conditions, or must wait because of unbalanced capacity. At this time, if the storage environment is poor, it may lead to oxidation and pollution of the metal surface

The separation of plating layer must be caused by poor adhesion between electroplating metal and substrate. How to find out the cause of poor adhesion is the focus of your problem. To solve this problem, we can simplify the problem into two types: poor adhesion caused by foreign matters and poor adhesion without foreign matters.

It is not easy to obtain good electroplating results if there are foreign matters left in the electroplating area, such as heavy oxide layer, poor degreasing treatment, poor micro etching treatment, insufficient water washing, etc. In the process of circuit board production, production is often suspended due to specific conditions, or must wait because of unbalanced capacity. At this time, if the storage environment is poor, it may lead to metal surface oxidation, pollution and other problems. In order to simplify the manufacturing process, some manufacturers will remove the degreasing treatment, which may lead to coating separation due to insufficient cleaning of the metal surface. The same is true for insufficient micro etching and insufficient water washing, which will leave a film on the metal surface that is not conducive to the formation of the electroplating layer.

Of course, this kind of phenomenon can not rule out the possibility of light resistance, organic residue and other problems. However, if the situation is serious, there is a problem even with electroplating, then the problem of coating separation will not be seen. Therefore, if the surface quality of the circuit board has been confirmed before entering the manufacturing process, it is recommended to focus on the pre-treatment and manufacturing process of the electroplating manufacturing process.

The electroplating layer of circuit board can be divided into the same metal electroplating and the different metal electroplating. Generally, the layer separation caused by the same metal electroplating is mostly due to pollution or insufficient cleaning. These are the so-called foreign matters that cause poor adhesion. However, there will be another case of no foreign matter pollution in the area of heterogeneous metal electroplating, the most typical of which is nickel electroplating surface treatment. As the main nickel plating solutions are nickel sulfate and nickel sulfonate, there will be different plating stresses due to the plating conditions and the use of the solution. In addition, the electroplating bath will accumulate organic pollution with the use of time, which will cause the plating stress to change again. Whether shrinkage stress or tensile stress, as long as the stress is too large, it may lead to coating separation. Therefore, most PCBA manufacturers will use nickel sulfonic acid bath for nickel electroplating, but the maintenance cost of this bath is high and the operation is troublesome. Good liquid medicine management and proper pre-treatment are relatively effective improvement methods, and it is not recommended to extend the front line to the previous process. The above is for your reference.

PCB manufacturers, PCB designers and PCBA processors will explain which process is related to PCB coating separation.