How PCB Fabrication is Done?
Paul Aisle was the first to design a printed circuit board or PCB in 1936. However, the wide application of this idea only begun in around 1950 with the United States Defense industry incorporating printed circuit boards in detonator systems for their bombs. Since then, PCB fabrication began so various areas in electronics can be supported. Today, almost all electronic devices utilize PCBs from cell phones to automobiles.
Before the PCB fabrication procedure can be started, it will require two kinds of software, which includes CAD (computer aided design) and CAM (computer aided manufacturing). Initially, CAD is used so that the circuit’s electronic schematic could be designed. Once the schematic design is completed, CAM can then be used so that engineers can produce a prototype of the PCB.
After finishing the prototype, engineers can then proceed with PCB fabrication. They begin by choosing which material will be best used in the PCB. PCB materials come in a variety of types, although among the most prevalent ones include CEM1, CEM5, FR1, FR4, Nalco, Rogers, Polyimide, Argon, and Bakelite. The PCB’s dimensions will be dependent on the design’s width, length, thickness and other requirements.
After carefully choosing the right materials, fabrication is carried out with the application of a thin copper coating onto the board. A photosensitive method will then be facilitated to print a circuit layout onto the board. Afterwards, photo engraving is done to get rid of part of the copper coating not included in the layout. As soon as this process is done, what’s left of the copper coating will serve as tracks that will be used for the printed circuit board. These tracks will be connected through a couple of procedures. First, a process involving mechanical milling is carried out using CNC (computer numerical control) machines to eliminate unnecessary copper out of the board. A printing process using silk screen will then be applied to coat parts of the board where tracks should exist.
This process of PCB fabrication completes a board with copper traces, but without the necessary components attached to the PCB. Mounting these components require holes to be drilled, which should be at points where electrical components will be placed. To drill these holes, lasers may be used although some have been utilizing drill bits created from tungsten carbide. After drilling the holes, hollow rivets can then be inserted. Alternatively, a process called electroplating may be done to coat the holes. This serves as a means for electrical connection to flow through the board’s layers.
The whole PCB is then coated with a certain type of masking material, which could be in the form of lead solder, Enter, immersion gold, flash gold, immersion silver, nickel, or other types. To complete the fabrication process, the board is then screen printed which makes labels and legends clearly visible and appear in their designated areas.
Before components could actually be mounted onto the printed circuit board, testing will be facilitated by the manufacturer. Even if experienced professionals create this part of an electronic device, certain faults could still occur. There are two primary kinds of malfunction that may happen upon completion of PCB fabrication: an open or a short.
A fault can be considered as an open if there is a point on the board that is missing a connection. A short is characterized by a connection that exists between at least two circuit points, even though there shouldn’t be any. Unfortunately, there are certain manufacturers that send finished boards to their customers even if they’ve not tested their product. This can potentially be problematic for the customer since the device that the board is meant to support may not function properly.
Today, almost all electronic devices utilize PCBs from cell phones to automobiles.A printing process using silk screen will then be applied to coat parts of the board where tracks should exist.