... over the entire group. That will make the fabricator's life much simpler. Bear in mind that a fabricator's spacing tolerances likely differ from yours. | PRINTED CIRCUIT BOARDS PRODUCTION | For example, take the drill data. When laying out a board, you usually work with finished hole sizes. However, a fabricator must drill a hole | PRINTED CIRCUIT BOARDS PRODUCTION | larger than the finished one, about 0.004" to 0.005" over, then plate down to the desired finished size. This can lead to problems in maintaining | PRINTED CIRCUIT BOARDS PRODUCTION | annular ring requirements and copper spacing on internal layers. To meet manufacturing specs, the fabricator might have to modify the data, and that's the last | PRINTED CIRCUIT BOARDS PRODUCTION | thing you want. So now we have an alternate reality: You've finished the PCB layout (check out those negative planes!). You output the 274X and | PRINTED CIRCUIT BOARDS PRODUCTION | IPC-D-356 netlist files. The data are fed into a fab analysis tool and run through their paces. Clearances are good. No possible soldermask flaking. Spacing | PRINTED CIRCUIT BOARDS PRODUCTION | between the drills is just right. You hand the data set to the fabricator, and voila! No ...
[ Printed Circuit Boards Production ]


... higher layer count multilayers, smaller holes and finer lines. These techniques, however, have not always been able to satisfy designer's often desperate needs to | PRINTED CIRCUIT BOARDS PRODUCTION | overcome real estate constraints whilst trying to maximise component configurations. As a result new alternatives such as buried vias, blind vias or a mixture of | PRINTED CIRCUIT BOARDS PRODUCTION | both have been successfully utilised by designers trying to maximise board real estate by increasing the density of lines and pads. However, many manufacturing and | PRINTED CIRCUIT BOARDS PRODUCTION | design issues must be addressed before adventuring down this path. Due to the many additional oper- ations, the cost of a blind or buried via | PRINTED CIRCUIT BOARDS PRODUCTION | board is significantly higher than that of a multilayer of the same layer count. | BURIED VIAS | A buried via is a copper-plated hole, | PRINTED CIRCUIT BOARDS PRODUCTION | imbedded in the board, that interconnects two internal layers. The buried via process starts by drilling holes on thin core laminate. These cores are then | PRINTED CIRCUIT BOARDS PRODUCTION | metallised, imaged and etched before being laminated. Individual ...
[ Printed Circuit Boards Production ]


... should contain the following information to ensure that the finished board is to your requirements. - Always required even when a drill file is | PRINTED CIRCUIT BOARDS PRODUCTION | supplied, to enable inspection of panels immediately after drilling and finished boards prior to despatching. Hole sizes must be clearly represented with distinct differences between | PRINTED CIRCUIT BOARDS PRODUCTION | each size. Tolerances are not required unless different to our standard of +0.1 / -0.05 mm. - Preferred with overall mechanical dimensions including notches, cutouts | PRINTED CIRCUIT BOARDS PRODUCTION | and slots. Also preferred is a positioning (datum) dimension (drilled hole is best). Tolerances are not required unless different to our standard of + / | PRINTED CIRCUIT BOARDS PRODUCTION | -0.25 mm. Other information required for all boards includes: board thickness (standard = 1.6mm) base copper thickness (std = 18mm) solder mask colour (std = | PRINTED CIRCUIT BOARDS PRODUCTION | green) solder mask type (std = liquid photoimageable) component legend colour (std = white) bare board testing requirement (std for multilayer and fine line production | PRINTED CIRCUIT BOARDS PRODUCTION | runs) Extra information ...
[ Printed Circuit Boards Production ]