Multilayer Circuit Boards The indication, which drillings or milling should be plated through or not plated through on a PCB or Printed Circuit Boards

... the more troublesome layers for fabricators. The solution here is a fabrication analysis tool that can handle such issues as clearances, coverage, webbing, and | MULTILAYER CIRCUIT BOARDS | so forth. For instance, most | FAB SHOPS | want the largest possible clearances in a solder layer so that mask doesn't end up on | MULTILAYER CIRCUIT BOARDS | pads. On the flip side, copper is not supposed to be exposed. The two requirements - no mask on pads and unwanted exposed copper - | MULTILAYER CIRCUIT BOARDS | must be balanced. It is not easy to do. How can the designer help? Devise a standardized clearance, or set the clearances at 1:1, and | MULTILAYER CIRCUIT BOARDS | let the shop do the soldermask enhancement. Here's another issue: | THE SOLDERMASK | webbing between pads on fine-pitch surface mount devices. Most masks can | MULTILAYER CIRCUIT BOARDS | go to 0.003" without the resist flaking off. However, if the pads are so tightly grouped that the dams between them are less than 0.003", | MULTILAYER CIRCUIT BOARDS | it's better to construct a mask opening over the entire group. That will make the fabricator's life much simpler. Bear in mind that a | ...
[ Multilayer Circuit Boards ]


... must be supplied with each new job and should contain the following information to ensure that the finished board is to your requirements. - | MULTILAYER CIRCUIT BOARDS | Always required even when a drill file is supplied, to enable inspection of panels immediately after drilling and finished boards prior to despatching. Hole sizes | MULTILAYER CIRCUIT BOARDS | must be clearly represented with distinct differences between each size. Tolerances are not required unless different to our standard of +0.1 / -0.05 mm. - | MULTILAYER CIRCUIT BOARDS | Preferred with | OVERALL MECHANICAL DIMENSIONS | including notches, cutouts and slots. Also preferred is a positioning (datum) dimension (drilled hole is best). Tolerances are | MULTILAYER CIRCUIT BOARDS | not required unless different to our standard of + / -0.25 mm. | OTHER INFORMATION REQUIRED FOR ALL BOARDS INCLUDES: | board thickness (standard = | MULTILAYER CIRCUIT BOARDS | 1.6mm) base copper thickness (std = 18mm) solder mask colour (std = green) solder mask type (std = liquid photoimageable) component legend colour (std = | MULTILAYER CIRCUIT BOARDS | white) bare board testing requirement (std for multilayer ...
[ Multilayer Circuit Boards ]


... AND TERMS OF PRINTED CIRCUIT BOARDS | | FEED-THRU OR VIAS | A plated-thru hole in a Printed Circuit Board that is used to | MULTILAYER CIRCUIT BOARDS | provide electrical connection between a trace on one side of the Printed Circuit Board to a trace on the other side. Since it is not | MULTILAYER CIRCUIT BOARDS | used to mount component leads, it is generally a small hole and pad diameter. | FIDUCIAL OPTICAL TARGET |. Also called OS. | FINAL COPPER | MULTILAYER CIRCUIT BOARDS | THICKNESS | The copper thickness stated in the PCB specification. This thickness is to be understood as the total thickness of copper foil + copper | MULTILAYER CIRCUIT BOARDS | plating. Fine-pitch SMD component with center-to-center terminal distances of less than 0,635 mm. Fluxing The process of removing oxides from a PCB to prepare it | MULTILAYER CIRCUIT BOARDS | for soldering. Fluxing lowers the surface tension of the solder and helps promote the formation of good solder fillets. Foil A thin continuous sheet of | MULTILAYER CIRCUIT BOARDS | metal, usually copper or aluminum, used as the conductor for printed circuits. Foils used for printed circuits are commonly 1 or 2 ...
[ Multilayer Circuit Boards ]