Precautions for PCB board process solutions
1. Splicing method:
Applicable: film with less dense lines and inconsistent deformation of each layer of film; especially suitable for the deformation of solder mask layer and multi-layer PCB board power supply film; not applicable: negative film with high line density, line width, and spacing less than 0.2mm;
Note: Minimize the damage to the wire when cutting, do not damage the pad. When splicing and duplicating, pay attention to the correctness of the connection relationship. 2. Change the hole position method:
Applicable: The deformation of each layer is consistent. Line-intensive negatives are also suitable for this method; not applicable: the film is not uniformly deformed, and local deformation is particularly severe.
Note: After using the programmer to lengthen or shorten the hole position, the hole position of the tolerance should be reset. 3. Hanging method:
Applicable; film that is undeformed and prevents distortion after copying; not applicable: distorted negative film.
Note: Dry the film in a ventilated and dark environment to avoid contamination. Make sure that the air temperature is the same as the temperature and humidity of the workplace. 4. Pad overlap method
Applicable: the graphic lines should not be too dense, the line width and line spacing of the PCB board are greater than 0.30mm; not applicable: especially the user has strict requirements on the appearance of the printed circuit board;
Note: The pads are oval after overlapping, and the halo around the edges of the lines and pads is easily deformed. 5. Photo method
Applicable: The deformation ratio of the film in the length and width directions is the same. When the re-drilling test board is inconvenient to use, only the silver salt film is applied. Not applicable: Films have different length and width deformations.
Note: The focus should be accurate when shooting to prevent line distortion. The loss of the movie is huge. In general, multiple adjustments are required to obtain a satisfactory PCB circuit pattern.