The PCB Fabrication Explanation


Prototype circuit boards

When it comes to the term PCB fabrication, there is certainly a great deal that can leave one very intimidated about the process. However, PCB fabrication is actually quite straightforward, not only in its explanation but also in its function and usefulness. PCB stands for printed circuit board.

A printed circuit board mechanically supports and electrically connects components using conductive tracks, pads, and other features. These materials are all etched from copper sheets and are laminated onto a substrate which is non-conductive. The components-capacitors, resistors, or active devices- are generally soldered on the printed circuit boards. If the PCB is not a prototype circuit board but actually more advanced, the PCB might contain components embedded in the substrate.

In addition to printed circuit board, there are other types of assemblies related to the PCB fabrication models. The first is called an integrated circuit, sometimes know as an IC or microchip, and the other is called a hybrid circuit.

Glass epoxy is the number one insulating substrate upon which almost all of the rigid PCBs are put together. This particular glass epoxy is known as FR-4. A very thin layer of copper foil is laminated to one or both sides of an F-4 panel. Interconnections are etched into copper layers. These are circuitry interconnections and produce the printed circuit boards in multiple layers. There are three methods to print the legend of PCB fabrication. The legends contain the component designators, the switch settings, the tests points and several other indications. These indications can prove to be very important when assembling, testing and servicing the circuit board. The circuit board is always in play when silk screen printing, liquid photo imaging, and ink jet printing are being managed.

Regarding manufacturing, whether it is circuit board prototyping or otherwise, manufacturing begins with the PCB fabrication data that is generated by CAD. This is Gerber layer images, Gerber or Excellon drill files, IPC-D-356 netlist, and component information. Neither the Gerber nor Excellon files in the fabrication data are ever used directly on the manufacturing equipment. They are, however, always read into the CAM (Computer Aided Manufacturing) software.

PCBs can be one sided (with one copper layer), they can be double sided (using two copper layers), or they can be multi-layered, having an outer layer and inner layers.


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