In 1936, the first printed circuit board (PCB) was made by Paul Eisle. However it wasn’t 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 found in almost all manufactured products including, automobiles, cellular telephones, computers, among others.
A Summary from the PCB Fabrication Processes – PCBs are initially fabricated with the aid of two kinds of software. Computer Aided Design (CAD) application is used to design the electronic schematic from the circuit to get produced. Right after the schematic is designed, Computer Aided Manufacturing (CAM) software is used by engineers to produce the PCB prototype.
When the PCB prototype was created, step one within the PCB production is always to select the material in the printed circuit board. There are numerous varieties of PCB materials available, but 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 has been selected, the first process is to use a coating of copper towards the entire board. The circuit layout will likely then be printed on the board with a photosensitive process. Then, a photo engraving process will likely be used to ensure that all the copper which is not part of the circuit layout will be etched out or taken from the board. The resulting copper creates the traces or tracks of the PCB circuit. To get in touch the circuit traces, two processes are utilized. A mechanical milling process uses CNC machines to get rid of 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 manufacturing process, the PCB board contains copper traces with no circuit components. To mount the components, holes has to be drilled on the points where electrical and electronics parts are put on the board. The holes are drilled with either lasers or a special kind of drill bit made from Tungsten Carbide. When the holes are drilled, hollow rivets are inserted into them or these are coated by an electroplating process, which produces the electrical link between the layers in the board. A masking material is then put on coat the entire PCB except for the pads and also the holes. There are many kinds 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 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 caliber of the PCB Board – Before placing the electrical and electronic components on the PCB, the board ought to be tested to confirm its functionality. Generally speaking, there are two varieties of malfunctions that will ysfurn a faulty PCB: a quick or perhaps an open. A “short” is a link between several circuit points which should not exist. An “open” is a point in which a connection should exist but will not. These faults has to be corrected before the PCB is assembled. Unfortunately, some rigid flex circuits tend not to test their boards before they may be shipped, which can cause problems at the customer’s location. So, quality testing is a crucial procedure of the PCB fabrication process. Testing ensures the PCB boards are in proper working condition just before component placement.