In 1936, the first printed circuit board (PCB) was created by Paul Eisle. However it was not until the 1950s when the U.S. Defense industry began integrating Printed circuit boards in their bomb detonator systems that printed circuit boards found wide application. PCBs are now utilized in nearly all manufactured products like, automobiles, cellular telephones, personal computers, and others.
An Overview of the PCB Fabrication Processes – PCBs are initially fabricated by using 2 kinds of software. Computer Aided Design (CAD) application is used to design the electronic schematic from the circuit to get produced. Following the schematic is made, Computer Aided Manufacturing (CAM) software program is utilized by engineers to create the PCB prototype.
When the PCB prototype is made, step one within the PCB production is to select the material in the printed circuit board. There are various varieties 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 style requirement dictates the proportions of the PCB (I.e., length, width and thickness).
Right after the material has become selected, the very first process is to apply a coating of copper to the entire board. The circuit layout will then be printed on the board by a photosensitive process. Then, a picture engraving process will be used so that each of the copper that is certainly not portion of the circuit layout will be etched out or taken off the board. The resulting copper creates the traces or tracks from the PCB circuit. To get in touch 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 used to protect the regions where traces must exist.
At this point in the flexible pcb manufacturer, the PCB board contains copper traces without the circuit components. To mount the constituents, holes should be drilled at the points where electrical and electronics parts are put on the board. The holes are drilled with either lasers or even a special kind of drill bit made from Tungsten Carbide. Once the holes are drilled, hollow rivets are inserted into them or they may be coated by an electroplating process, which produces the electrical link between the layers from the board. A masking material will be placed on coat the entire PCB except for the pads and also the holes. There are numerous 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 caliber of the PCB Board – Just before placing the electrical and electronic components on the PCB, the board should be tested to ensure its functionality. Generally speaking, the two main kinds of malfunctions that will ysfurn a faulty PCB: a short or an open. A “short” is a connection between 2 or more circuit points which should not exist. An “open” is a point when a connection should exist but does not. These faults must be corrected prior to the PCB is assembled. Unfortunately, some rigid flex printed circuit boards tend not to test their boards before these are shipped, which can cause problems at the customer’s location. So, quality tests are a vital procedure of the PCB fabrication process. Testing ensures the PCB boards are in proper working condition just before component placement.