In 1936, the first 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. Printed circuit boards are utilized in nearly all manufactured products including, automobiles, cellular telephones, computers, among others.
A Summary from the PCB Fabrication Processes – PCBs are initially fabricated by using two kinds of software. Computer Aided Design (CAD) software is used to design the electronic schematic in the circuit to get produced. Following the schematic is made, Computer Aided Manufacturing (CAM) software program is employed by engineers to generate the PCB prototype.
Once the PCB prototype is designed, the initial step inside the PCB production is to pick the material in the printed circuit board. There are various varieties 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 style requirement dictates the size of the PCB (I.e., length, width and thickness).
After the material has become 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 that is not part of the circuit layout will likely be etched out or removed from the board. The resulting copper produces the traces or tracks from the PCB circuit. To get in touch the circuit traces, two processes are employed. A mechanical milling process uses CNC machines to remove the unnecessary copper through the board. Then, an etch-resistant, silk-screen, printing process is applied to protect the regions where traces must exist.
At this stage inside the flexible pcb manufacturing process, the PCB board contains copper traces without the circuit components. To mount the constituents, holes should be drilled in the points in which the electrical and electronics parts are positioned on the board. The holes are drilled with either lasers or a special kind of drill bit made from Tungsten Carbide. Once 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 in the board. A masking material will then be put on coat the entire PCB excluding the pads and also the holes. There are many 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 ultimate part of the PCB fabrication process is to screen print the board so labels and the legend appear at their proper locations.
Testing the caliber of the PCB Board – Before placing the electrical and electronic components on the PCB, the board should be tested to verify its functionality. In general, the two main types of malfunctions that will ysfurn a faulty PCB: a brief or even an open. A “short” is a link between several circuit points which should not exist. An “open” is really a point in which a connection should exist but does not. These faults has to be corrected prior to the PCB is assembled. Unfortunately, some rigid flex printed circuit boards usually do not test their boards before these are shipped, which can cause problems in the customer’s location. So, quality tests are a crucial process of the PCB fabrication process. Testing ensures the PCB boards have been in proper working condition just before component placement.