The process of printing a layer of blue glue on the PCB by screen printing or aluminum screen printing
Peelable Solder Mask is a process that uses screen printing or aluminum screen printing to print a layer of blue glue on some parts of the PCB, and after curing, it acts as a protection and solder mask. It is estimated that everyone in the PCB industry understands the role of blue glue, but the process is estimated to be less clear. Beton Technology will explain the operation process of printing blue glue.
Peelable Solder Mask operation process:
- Screen printing method
First use film to expose the net, then print oil on the board surface through the screen, and then cure (that is, bake the board).
- Aluminum screen printing method
Print the graphics on the board according to the customer’s requirements through the aluminum sheet, and then solidify.
- How to choose between the two methods
A. Only holes with a diameter of less than 1mm need to be sealed with blue glue, and the Peelable Solder Mask is directly used for screen printing. These holes can be sealed at the same time as the printing plate surface, and there is no need for aluminum sheet sealing. At this time, we only need to write the blue plastic film tool on the MI, and there is no need to write the backing plate aluminum tool.
B. If there are holes with a diameter greater than 1mm that need to be sealed with blue glue, and the shape of the blue glue is regular, you can directly use the aluminum sheet silk screen printing method. At this time, we only need to write the aluminum sheet tool on the MI, and there is no need to write the film tool; However, the shape of the blue glue is irregular, and it is inconvenient to use aluminum sheet to form, so it is necessary to use screen printing to print the surface of the plate and use aluminum sheet to seal the holes at the same time. At this time, we need to write both blue plastic film and aluminum sheet on our MI.