In 1936, the very first printed circuit board (PCB) was created by Paul Eisle. But it was not 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 utilized in almost all manufactured products like, automobiles, cellular telephones, personal computers, and others.
A Summary in the PCB Fabrication Processes – PCBs are initially fabricated with the aid of two types of software. Computer Aided Design (CAD) application is employed to design the electronic schematic of the circuit to be produced. Following the schematic was created, Computer Aided Manufacturing (CAM) software is utilized by engineers to generate the PCB prototype.
Once the PCB prototype was created, the initial step within the pcb fabrication specifications would be to pick the material of the printed circuit board. There are various types of PCB materials available, but the popular ones, based on the application as well as 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 very first process is to use a coating of copper for the entire board. The circuit layout will be printed on the board by a photosensitive process. Then, a photograph engraving process will be used so that all of the copper which is not area of the circuit layout will be etched out or taken from the board. The resulting copper creates the traces or tracks in the PCB circuit. For connecting the circuit traces, two processes are utilized. A mechanical milling process will use CNC machines to eliminate the unnecessary copper from the board. Then, an etch-resistant, silk-screen, printing process is used to protect 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 ingredients, holes must be drilled in the points in which the electrical and electronics parts are put on the board. The holes are drilled with either lasers or perhaps a special kind of drill bit made of Tungsten Carbide. When the holes are drilled, hollow rivets are inserted into them or these are coated by an electroplating process, which creates the electrical connection between the layers of the board. A masking material will then be placed on coat the whole PCB excluding the pads and also the holes. There are many kinds of masking material like, 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 ultimate step in the PCB fabrication process is always to screen print the board so labels and also the legend appear at their proper locations.
Testing the Quality of the PCB Board – Before placing the electrical and electronic components on the PCB, the board needs to be tested to ensure its functionality. Generally speaking, the two main types of malfunctions that can ysfurn a faulty PCB: a short or even an open. A “short” is actually a link between several circuit points that will not exist. An “open” is a point when a connection should exist but does not. These faults must be corrected ahead of the PCB is assembled. Unfortunately, some rigid flex circuit boards tend not to test their boards before these are shipped, which can lead to problems on the customer’s location. So, quality tests are a vital process of the PCB fabrication process. Testing ensures the PCB boards are in proper working condition prior to component placement.