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 now found in nearly all manufactured products like, automobiles, cellular telephones, computers, and others.
An Overview of the PCB Fabrication Processes – PCBs are initially fabricated with the aid of 2 kinds of software. Computer Aided Design (CAD) application is utilized to design the electronic schematic in the circuit to be produced. Following the schematic is made, Computer Aided Manufacturing (CAM) software is utilized by engineers to generate the PCB prototype.
When the PCB prototype is made, the initial step within the PCB production is always to select the material of the printed circuit board. There are various types of PCB materials available, nevertheless 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 and style requirement dictates the dimensions of the PCB (I.e., length, width and thickness).
Right after the material has been selected, the initial process is to apply a coating of copper for the entire board. The circuit layout will likely then be printed on the board by a photosensitive process. Then, a photograph engraving process will be used so that all the copper that is not part of the circuit layout will likely 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 employed. A mechanical milling process uses CNC machines to remove 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 time inside the flexible pcb manufacturer, the PCB board contains copper traces with no circuit components. To mount the ingredients, holes has to 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 creates the electrical link between the layers in the board. A masking material will then be applied to coat the entire PCB excluding the pads and also the holes. There are numerous types of masking material including, 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 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 Quality of the PCB Board – Prior to placing the electrical and electronic components on the PCB, the board should be tested to ensure its functionality. In general, the two main types of malfunctions that can ysfurn a faulty PCB: a short or even an open. A “short” is actually a link between two or more circuit points that will not exist. An “open” is a point when a connection should exist but fails to. These faults must be corrected ahead of the PCB is assembled. Unfortunately, some rigid flex printed circuit boards usually do not test their boards before they are shipped, which can cause problems at the customer’s location. So, quality testing is a crucial process of the PCB fabrication process. Testing ensures the PCB boards are in proper working condition before component placement.