The production process of PCB must be familiar to everyone. Then, what inspection requirements do PCB proofing manufacturers have in the production process of circuit boards? Please follow the editor to take a look at the inspection standards for PCB proofing.
1. Cutting
Check the specification model and cutting size of the substrate according to the product processing or cutting specification drawings. The latitude and longitude direction, length, width and verticality of the substrate are within the range specified on the drawing.
2. Screen printing
First, check whether the screen mesh, screen tension, and film thickness meet the specified requirements;
Then, check the integrity of the graphics, there are no pinholes, gaps or residual film; check with the photo base plate, the graphics positioning size is consistent, the line width and line spacing, the size of the connection pad or the character mark are all consistent.
3. Surface cleaning
The surface of the chemically cleaned PCB board must not be oxidized or polluted, and should be dried after cleaning.
4. Line printing
Check the integrity of the circuit graphics, there is no open circuit, pinhole, gap or short circuit; check with the photographic plate, the graphics positioning size is consistent, the line width and line spacing are consistent, and the error is within the allowable range.
5. Etching
Check the integrity of the circuit pattern, there are no open circuits, pinholes, gaps or short circuits; check with the photo master, there is no over-etching (the circuit is too thin) or under-etching (the circuit is too thick).
6. Solder mask
First of all, check the integrity of the solder mask pattern, there are no missing prints, pinholes, gaps or ink bleeding, upper plate, excess ink dots; it is consistent with the positioning size of the circuit pattern, and the error is within the allowable range.
Secondly, check the curing degree of the solder resist, and test the solder resist layer on the copper conductor surface with a pencil, and the pencil hardness should be above 3H.
Again, check the binding force of the solder resist. The solder resist layer on the copper conductor surface is pasted and pulled up with an adhesive tape. There should be no peeling solder resist on the tape.
7. Front and back character marks
Check the integrity of the character mark graphics, there are no missing prints, pinholes, gaps or ink bleeding, upper plates, and excess ink dots; it is consistent with the positioning size of the line graphics, the error is within the allowable range, and the character marks can be correctly identified.
