After the following procedures, the finishing work shall be undertaken by the operator responsible for PCB board testing and repair, unless otherwise arranged. The final installer shall be responsible for reviewing and correcting the reinstallation.
Remarks: The grinding process between silk screen and solder mask may be omitted. It can be soldered first and then screen printed, depending on the substrate.
PCB material are divided into: 94HB, fireproof board (94VO, FR-1, FR-2), semi-glass (22F, CEM-1, CEM-3), and full glass (FR-4).
Via is one of the important components of a multi-layer PCB. The cost of drilling is usually 30% to 40% of the cost of PCB board. Simply put, each hole in the PCB can be called a via.
The film consists of a protective film, an emulsion layer, a bonding film, a film base and an antihalation layer. The main components are silver salt photosensitive materials, gelatin and pigments. Under the action of light, the silver salt can be reduced to the center of the silver core, but it is not dissolved in water. Therefore, it can be suspended in a gelatin state and coated on the substrate. The emulsion also contains a pigment to sensitize. The exposed film is then obtained by actinic action.