Design Process Behind Printed Circuit Board Assemblies

The PCB, or printed circuit board, is the central element in every electronic system. The board is the base on which the entire circuit is mounted, whether it is surface mounting or perforated board. These boards are meticulously designed to be efficient and compact, planned for every circuit individually.

The PCB Assembly Design Process

Different printed circuit board assemblies may contrast in certain nuances but the main PCB assembly design steps are common for all of them. The physical manufacturing part will involve laser cutting/drilling, CNC machining, etching, plating and optical inspection. Then there are testing methods for the PCB and its electrical components.

Design Process Behind Printed Circuit Board Assemblies

This is all preceded by the design part. Here are its stages.

Step One: Digitally Designing the PCB

In the old days before modern imaging/design software was available, the PCB architecture was simply drawn on paper. Modern PCB assembly design programs have a pre-made library of components used in printed circuit board assemblies which the designer puts in place.

Step Two: The PCB Assembly Film is Generated

The finalized circuit board diagram is taken and used by the software to produce a mask, or negative, of the design, which is then printed onto a clear plastic sheet. This resembles somewhat the old-fashioned slides, or x-ray prints. The value of this is having a tangible, real-size model of the PBC prior to actually manufacturing one.

Step Three: Material Selection

Most modern printed circuit board assemblies are made using fiberglass with copper foil bonded onto one or both of their sides. Some will be made of unbreakable glass or paper phenolic (which is mostly used in household electrical appliances).

Step Four: Drill Holes Preparation

Most PCBs will have pre-drilled holes for certain components, and those are made using carbide drills or similar machinery. The pattern, as well as other specifications (like drill bit sizes for example), are stored as part of the design in a file that get transferred to the machine which then executes it.

Step Five: Image Application

The image is printed on the PCB by different means, such as plotters, printers or hand applications. This, however, takes us beyond the design stage and into manufacturing, where the next steps are cutting, stripping, etching, and testing. Those we may discuss in future articles.

This concludes the description of PXB design steps. Hope this gave you a general idea of the process.

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