What is the cause of white spots on CB substrate and how to solve them?


Today, we will discuss the common problem encountered by warehouse material personnel in PCB manufacturing factories,2 oz copper thickness in mm which is the phenomenon of white spots or spots on the PCB substrate during cutting.

What is the reason for this problem? Many people have similar questions, right!

In fact, the main reason for this is the influence of external environment, such as temperature, humidity, and other factors.

If we put the substrate with white spots or spots into production, it will cause considerable trouble to the production line. So, how should we solve this problem?

Firstly, we need to understand the causes of this problem. The main reasons for white spots or spots on PCB substrates are:

① Improper thermal stress on the board can also cause white spots and spots;

② The impact of mechanical external forces on the board causes local separation of resin and glass fibers;

③ The local material is infiltrated by fluorinated chemicals and corrodes the woven points of glass fiber cloth,plated through hole vs via forming regular white spots (severe white spots appear as square).

Next, let's take a look at the solution:

① In case of control failure such as hot air leveling and infrared hot melting, the effect of thermal stress can lead to defects in the substrate. Therefore, we need to strengthen the control and monitoring of these processes;

② Minimize or reduce the vibration phenomenon during the machining process as much as possible to reduce the effect of external mechanical forces. This can be achieved by optimizing equipment and process parameters;

③ When removing the tin lead alloy coating, it is easy to occur between the gold plated plug piece and the plug piece. Therefore, we need to pay attention to selecting appropriate tin removal lead water and operating processes.

Through the above methods, we can effectively solve the problem of white spots or spots on PCB substrates, improve production efficiency and product quality.