During the PCB-processing, the inner wet film uses the micro-etching effect of sulfuric acid to remove oxides from the surface of the substrate and roughen the surface in order to improve the adhesion of the coated ink to the board surface. This allows for better adhesion of the coated ink to the board surface. On a surface that has been well cleaned, the photographic wet film is coated to form the inner layer. The environment of the workshop calls for purification of the class 10,000 variety. It is possible to save personnel and reduce the amount of manual handling with the completely automatic robotic arm plate accepting and releasing machine. Automatic exposure equipment that transforms the photographic sensitivity of the ink into a polymer to achieve graphic transfer. This is accomplished by irradiating the ink with ultraviolet light, which causes the ink on the board to go from monomer to polymer. LDI exposure machine laser direct imaging exposure machine, no film alignment
