In 1936, the initial printed circuit board (PCB) was made by Paul Eisle. However 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. Printed circuit boards are utilized in virtually all manufactured products including, automobiles, cellular telephones, personal computers, among others.
A Summary in 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 was created, Computer Aided Manufacturing (CAM) software program is utilized by engineers to generate the PCB prototype.
When the PCB prototype is made, the initial step within the PCB production would be to choose the material from the printed circuit board. There are many different types of PCB materials available, however 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 design requirement dictates the dimensions of the PCB (I.e., length, width and thickness).
After the material has become selected, the first process is to apply a coating of copper to the entire board. The circuit layout will likely then be printed on the board by a photosensitive process. Then, a photograph engraving process is going to be used in order that each of the copper that is certainly not portion of the circuit layout is going to be etched out or taken off the board. The resulting copper creates the traces or tracks of the PCB circuit. For connecting the circuit traces, two processes are employed. A mechanical milling process uses CNC machines to eliminate the unnecessary copper from the board. Then, an etch-resistant, silk-screen, printing process is used to pay for the regions where traces must exist.
At this stage inside the flexible pcb, the PCB board contains copper traces with no circuit components. To mount the components, 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 perhaps a special type of drill bit manufactured 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 connection between the layers from the board. A masking material will be put on coat the entire PCB except for the pads and the holes. There are numerous 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 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 – Just before placing the electrical and electronic components on the PCB, the board ought to be tested to confirm its functionality. Generally, there are two kinds of malfunctions that can ysfurn a faulty PCB: a quick or even an open. A “short” is actually a connection between two or more circuit points that will not exist. An “open” is really a point where a connection should exist but fails to. These faults should be corrected ahead of the PCB is assembled. Unfortunately, some rigid flex circuits usually do not test their boards before they may be shipped, which can lead to problems at the customer’s location. So, quality tests are a crucial procedure of the PCB fabrication process. Testing ensures the PCB boards have been in proper working condition just before component placement.