In 1936, the initial printed circuit board (PCB) was developed by Paul Eisle. But it wasn’t until the 1950s when the U.S. Defense industry began integrating PCBs in their bomb detonator systems that printed circuit boards found wide application. PCBs are used in nearly all manufactured products like, automobiles, cellular telephones, personal computers, and others.
An Overview in the PCB Fabrication Processes – PCBs are initially fabricated by using two types of software. Computer Aided Design (CAD) software program is used to design the electronic schematic of the circuit to become produced. After the schematic is made, Computer Aided Manufacturing (CAM) software is used by engineers to generate the PCB prototype.
Once the PCB prototype is designed, step one within the PCB production would be to choose the material of the printed circuit board. There are numerous varieties of PCB materials available, however the popular ones, based on the application and a customer’s requirements, include: Alumina, Arlon, Bakelite, CEM1, CEM5, Ceramic, FR1, FR4, FR4 High Temperature, GeTek, Nelco, Polyimide and Rogers.The design requirement dictates the dimensions of the PCB (I.e., length, width and thickness).
Following the material has been selected, the initial process is to use a coating of copper for the entire board. The circuit layout will likely then be printed on the board with a photosensitive process. Then, a photo engraving process will likely be used so that all of the copper that is certainly not area of the circuit layout will likely be etched out or taken from the board. The resulting copper produces the traces or tracks of the PCB circuit. For connecting the circuit traces, two processes are employed. A mechanical milling process will use CNC machines to remove the unnecessary copper from the board. Then, an etch-resistant, silk-screen, printing process is used to pay for the regions where traces must exist.
At this time within the flexible pcb manufacturer, the PCB board contains copper traces without any circuit components. To mount the components, holes has to be drilled in the points where the electrical and electronics parts are placed on the board. The holes are drilled with either lasers or even a special sort of drill bit manufactured from Tungsten Carbide. When the holes are drilled, hollow rivets are inserted into them or they may be coated by an electroplating process, which creates the electrical link between the layers of the board. A masking material is then placed on coat the entire PCB excluding the pads and the holes. There are numerous kinds of masking material such as, lead solder, lead free solder, OSP (Entek), deep/hard gold (electrolytic nickel gold), immersion gold (electroless nickel gold – ENIG), wire bondable gold (99.99% pure gold), immersion silver, flash gold, immersion tin (white tin), carbon ink, and SN 100CL, an alloy of tin, copper, and nickel. The last part of the PCB fabrication process is to screen print the board so labels as well as the legend appear at their proper locations.
Testing the standard of the PCB Board – Just before placing the electrical and electronic components on the PCB, the board should be tested to confirm its functionality. Generally, there are 2 kinds of malfunctions that can ysfurn a faulty PCB: a quick or perhaps an open. A “short” is a link between 2 or more circuit points that will not exist. An “open” is a point when a connection should exist but does not. These faults has to be corrected before the PCB is assembled. Unfortunately, some rigid flex circuits usually do not test their boards before they may be shipped, which can lead to problems at the customer’s location. So, quality testing is a critical procedure for the PCB fabrication process. Testing ensures the PCB boards will be in proper working condition before component placement.