The most effective way to increase the density of PCB circuit boards is to reduce the number of through holes, and accurately set blind holes and buried holes to achieve.
1. Blind hole definition
a: Compared with through holes, through holes refer to holes drilled through all layers, and blind holes are non-drilled through holes.
b: Blind hole subdivision: blind hole (BLINDHOLE), buried hole BURIEDHOLE (outer layer is not visible); c: Distinguish from the production process: blind holes are drilled before lamination, while through holes are drilled after lamination .
2. Circuit board manufacturing method of Shenzhen circuit board factory
A: Drill belt:
(1): Select the reference point: select the through hole (that is, a hole in the first drill belt) as the unit reference hole. (2): Each blind hole drilling strip needs to select a hole and mark its coordinates relative to the unit reference hole.
(3): Pay attention to explain which drill belt corresponds to which layers: both the unit hole diagram and the drill nozzle table must be marked, and the front and rear names must be consistent; the hole diagram should not appear with abc, and the front is used 1st, The case indicated by 2nd.
Note that when the laser hole is nested with the buried hole in the inner layer, that is, the holes of the two drill strips are at the same position, it is necessary to ask the customer to move the position of the laser hole to ensure the electrical connection. B: Shenzhen circuit board factory is producing pnl board edge process hole: ordinary PCB multilayer circuit board: no drilling in the inner layer;
(1): Rivets gh, aoigh, and etgh are all punched out after etching the plate
(2) : target hole (drilling gh) ccd: copper skin needs to be removed on the outer layer, x-ray machine: directly punch out, and note that the length of the long side is 11inch,
Blind hole plate:
All tooling holes are drilled out, pay attention to the rivets must be drilled out to avoid misalignment. (aoigh is also produced for beer), and the edge of the pnl board needs to be drilled to distinguish each board.
3. Film modification:
(1): Indicate that the film will produce the positive film, and the negative film:
General principles: the plate thickness is greater than 8mil (without copper) go through the positive film process; plate thickness less than 8mil (without copper) go through the negative film process (thin plate);
When the line is thick and the line gap is large, the copper thickness at d/f should be considered, not the bottom copper thickness. The blind hole ring can be 5mil instead of 7mil. The inner independent pad corresponding to the blind hole needs to be reserved. Holes cannot be ringless.
4. The process of Shenzhen circuit board factory:
The method of buried hole board is the same as that of ordinary double-sided circuit board.
