In 1936, the 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 used in almost all manufactured products including, automobiles, cellular telephones, personal computers, among others.
An Overview from the PCB Fabrication Processes – PCBs are initially fabricated with the use of two kinds of software. Computer Aided Design (CAD) software program is utilized to design the electronic schematic of the circuit to get produced. Right after the schematic is made, Computer Aided Manufacturing (CAM) application is used by engineers to generate the PCB prototype.
Once the PCB prototype is designed, the initial step inside the PCB production is to choose the material in the printed circuit board. There are many different kinds of PCB materials available, nevertheless the popular ones, based on the application along with a customer’s requirements, include: Alumina, Arlon, Bakelite, CEM1, CEM5, Ceramic, FR1, FR4, FR4 High Temperature, GeTek, Nelco, Polyimide and Rogers.The design and style requirement dictates the proportions of the PCB (I.e., length, width and thickness).
Right after the material continues to be selected, the very first process is to use a coating of copper towards the entire board. The circuit layout will likely then be printed on the board by a photosensitive process. Then, a photograph engraving process will be used to ensure that all the copper which is not area of the circuit layout will be etched out or taken off the board. The resulting copper creates the traces or tracks of the PCB circuit. To connect the circuit traces, two processes are utilized. A mechanical milling process will make use of CNC machines to eliminate the unnecessary copper from the board. Then, an etch-resistant, silk-screen, printing process is applied to cover the regions where traces must exist.
At this point inside the flexible pcb, the PCB board contains copper traces with no circuit components. To mount the components, holes must be drilled in the points where electrical and electronics parts are positioned on the board. The holes are drilled with either lasers or even a special type of drill bit made from Tungsten Carbide. When the holes are drilled, hollow rivets are inserted into them or they are coated by an electroplating process, which produces the electrical link between the layers from the board. A masking material will then be applied to coat the complete PCB excluding the pads and the holes. There are lots of varieties 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 last part of the PCB fabrication process is always to screen print the board so labels and the legend appear at their proper locations.
Testing the standard of the PCB Board – Before placing the electrical and electronic components on the PCB, the board ought to be tested to ensure its functionality. In general, there are two types of malfunctions that can ysfurn a faulty PCB: a brief or an open. A “short” is actually a connection between 2 or more circuit points which should not exist. An “open” is really a point when a connection should exist but does not. These faults should be corrected before the PCB is assembled. Unfortunately, some rigid flex printed circuit boards usually do not test their boards before these are shipped, which can lead to problems in the customer’s location. So, quality testing is a vital procedure for the PCB fabrication process. Testing ensures the PCB boards will be in proper working condition prior to component placement.