In 1936, the initial printed circuit board (PCB) was created 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 found in virtually all manufactured products like, automobiles, cellular telephones, computers, and others.
A Summary of the PCB Fabrication Processes – PCBs are initially fabricated by using 2 kinds of software. Computer Aided Design (CAD) software program is utilized to design the electronic schematic in the circuit to get produced. After the schematic is made, Computer Aided Manufacturing (CAM) software is employed by engineers to create the PCB prototype.
Once the PCB prototype was created, the initial step within the pcb fabrication specifications is always to select the material from the printed circuit board. There are many different types of PCB materials available, however 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 requirement dictates the size of the PCB (I.e., length, width and thickness).
Following the material continues to be selected, the first process is to apply a coating of copper towards the entire board. The circuit layout will then be printed on the board by a photosensitive process. Then, a picture engraving process will likely be used in order that all of the copper that is certainly not area of the circuit layout will likely be etched out or taken off the board. The resulting copper produces the traces or tracks from the PCB circuit. To connect the circuit traces, two processes are used. A mechanical milling process will use CNC machines to get rid of the unnecessary copper through the board. Then, an etch-resistant, silk-screen, printing process is used to protect the regions where traces must exist.
At this time inside the flexible pcb manufacturer, the PCB board contains copper traces without any circuit components. To mount the constituents, holes should be drilled at the points in which the electrical and electronics parts are positioned on the board. The holes are drilled with either lasers or even a special type of drill bit manufactured 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 connection between the layers from the board. A masking material will then be put on coat the entire PCB with the exception of the pads as well as the holes. There are numerous types 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 final part of the PCB fabrication process is to screen print the board so labels and also the legend appear at their proper locations.
Testing the Quality of the PCB Board – Prior to placing the electrical and electronic components on the PCB, the board needs to be tested to ensure its functionality. In general, the two main kinds of malfunctions that will ysfurn a faulty PCB: a short or an open. A “short” is really a link between 2 or more circuit points that should not exist. An “open” is a point where a connection should exist but does not. These faults should be corrected ahead of the PCB is assembled. Unfortunately, some rigid flex printed circuit boards tend not to test their boards before they are shipped, which can cause problems at the customer’s location. So, quality tests are a crucial procedure for the PCB fabrication process. Testing ensures the PCB boards have been in proper working condition just before component placement.