The manufacturing process of DOUBLE LAYER PCB BOARD
1 Plot negative film ( photo-plot the negative drawing );
2 Cutting the copper clad laminate ( keep20mmbreak-tab )
3 Drilling hole ( LAMINATE thickness is2.0mm, from drilling bit point to LAMINATE is 1.0-1.5mm, from the smallest drill hole to the biggest drill hole diameter in sequence );
4 Brush and Polish the DOUBLE LAYER PCB BOARD surface to swap off the smear, blurs, furs left after drilling and other residue;
5 Plate copper ( 30mins, the current is around4.5A/m2 );
6 Print photo-sensible circuit pattern ink onto the surface of DOUBLE LAYER PCB BOARD and then cure, film exposure and developing;
7 Plate tin ( around 20-30mins, the current is around 1.5-2.0A/dm2 on the effective area, try the min current first and then fetch it out to check after 3-5mins, if the layer is thin means the current is smaller than expectation, if the surface reflection is white which means the current level is appropriate );
8 After water rinsing these DOUBLE LAYER PCB BOARD and get strip off the film covered on the it, comes to one of the most important steps is ETCHING, strip off the TIN after ETCHING;
9 Print photo-sensitive solder resist ink on the DOUBLE LAYER PCB BOARD by 90T silkscreen frame, the aspect ratio of photo-sensitive ink to curing solution is 3:1, if the ink is too dense to print on the DOUBLE SIDED PCB BOARD, then need to add more diluent to low down is density; Cure the ink after being printed onto the DOUBLE SIDED PCB BOARD, exposure and developing;
10 Print photo-sensitive legend ink by 120T silkscreen frame, the aspect ratio of photo-sensitive ink to curing solution is 3:1, if the ink is too dense to print on the DOUBLE LAYER PCB BOARD, then need to add more diluent to low down is density; Cure the ink after being printed onto the DOUBLE LAYER PCB BOARD;