How Does Printing Circuit Boards Differ From Circuit Board Manufacturing?

Printing Circuit Boards Differ From Circuit Board Manufacturing

In order for manufacturers to create printing circuit boards that work correctly, they need precise design data. To get this, engineers use a process known as verification and clearance that checks the entire board to ensure it’s free from any errors or flaws. This step is crucial, and it helps eliminate products from the production line that don’t meet customer specifications or could cause damage to other components. It also saves time and resources as it allows an engineer to review the design for any issues before moving on to the printing phase.

The first step of the printed circuit board fabrication process is imaging the PCB’s layers. This is done with a plotter printer, and each layer of the inner and outer boards as well as the solder mask gets its own film. The films are then lined up and a hole, called a registration hole, is punched through them using a machine. This helps align the films for printing later on in the circuit board manufacturing process.

Once the registration holes are in place, technicians add copper to a laminate material for the inner layer of the circuit board. This is a process called “etching.” To do this, they follow the Gerber files that specify where the copper should go on the circuit board. Areas that are exposed to light during this process harden, and the remaining areas are chemically removed. This leaves behind the traces and other regions of the circuit board that are supposed to be copper.

How Does Printing Circuit Boards Differ From Circuit Board Manufacturing?

For the outer layer, a similar process happens, except that a pre-printed non-reproducing grid on the mylar aids in laying out the component pin pads and traces. These are then etched to reveal the copper. For the most complex PCBs, up to 40 layers can be used, and they are typically arranged in pairs for high-quality power distribution and superior shielding against noise.

The bare circuit board is then populated with the individual electronic components, or “stuffed.” This is either done through-hole or surface-mount technology, depending on the needs of the final product. Through-hole technology involves inserting the component leads into holes surrounded by conductive pads; the traces connect to them. Surface-mount technology, on the other hand, involves placing them onto conductive pads. Solder paste is then applied to the pad areas, and the components are placed on them and soldered in.

Finally, a visual inspection is performed to verify that the populated circuit board meets its design specifications. This is referred to as an AOI inspection, and it’s crucial for making sure the finished product functions properly. It can spot any issues like extra copper left over from the etching process or mismatched components that would otherwise prevent it from working.

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