A Brief Guide to Printed Circuit Boards

Today, printed circuit boards are an integral part of almost every device, such as cars, cell phones, computers and more. To make a customized PCB, first the electronic circuit diagram required is prepared using the software. After that, the PCB prototype is developed using CAMS technology.

How to Make a Printed Circuit Board

The size and thickness of the board depends on the circuit requirements. The substrate is coated with a copper layer. Then, using photosensitive coating, the circuit diagram is printed on the board. Undesired copper is removed from the tray to form copper “footprints”, called dashes. This process is known as photogravure. There are two other common methods used to develop connection traces. PCB machining is a mechanical system where unwanted copper is removed with CNC machines. Another process is screen printing, where special paint that is resistant to corrosion is used to cover areas where copper traces need to be made.

Once the board is finished with copper traces, holes are drilled in the board to assemble leaded electrical and electronic components. For drilling, special carbide or tungsten carbide drills are used. The holes made are filled with hollow rivets or coated through an electrogalvanization process, thus forming an electrical connection between the various layers. The next step is to coat the entire board, except for holes and cushions, with mask material. The last step is screen printing, where the caption and text are printed on the PCB.

A Brief Guide to Printed Circuit Boards

PCB testing

Prior to assembly of the components or delivery of the Printed Circuit Boards, the board must be tested to find possible “short” and “openings” that could lead to a board that does not work. A “short” indicates the existence of an unwanted connection and an “open” indicates that two points that should be connected are not connected. All of these errors must be corrected prior to assembly of the PCB. It is important to note that not all PCB fabrication shops test the boards before shipping, sometimes it is considered an additional cost but vital to provide a fully functional board before adding components.

PCB assembly

When the board is ready, the components are assembled and added to the surface according to the circuit diagram. Some of the common assembly techniques are the overhang construction and the construction through holes. Sometimes a combination of these two techniques is also used for assembly.

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