In 1936, the very 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. Printed circuit boards are now found in almost all manufactured products including, automobiles, cellular telephones, pcs, and others.
A Summary of the PCB Fabrication Processes – PCBs are initially fabricated by using two types of software. Computer Aided Design (CAD) software program is used to design the electronic schematic of the circuit to get produced. Right after the schematic is made, Computer Aided Manufacturing (CAM) software program is utilized by engineers to create the PCB prototype.
Once the PCB prototype is designed, step one within the PCB production is always to select the material of the printed circuit board. There are various types of PCB materials available, but the popular ones, based on the application and 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).
After the material continues to be 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 by a photosensitive process. Then, a picture engraving process will likely be used in order that all the copper that is certainly not portion of the circuit layout will likely be etched out or taken from the board. The resulting copper creates the traces or tracks from the PCB circuit. To connect the circuit traces, two processes are utilized. A mechanical milling process will make use of CNC machines to remove the unnecessary copper through the board. Then, an etch-resistant, silk-screen, printing process is applied to pay for the regions where traces must exist.
At this stage within the flexible pcb manufacturing process, the PCB board contains copper traces with no circuit components. To mount the components, holes has to 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. When the holes are drilled, hollow rivets are inserted into them or they are coated by an electroplating process, which creates the electrical connection between the layers in the board. A masking material will be placed on coat the complete PCB excluding the pads and the holes. There are lots of types 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 always to screen print the board so labels and the legend appear at their proper locations.
Testing the caliber of the PCB Board – Prior to placing the electrical and electronic components on the PCB, the board ought to be tested to verify its functionality. Generally, the two main kinds of malfunctions that can ysfurn a faulty PCB: a short or an open. A “short” is actually a connection between several circuit points which should not exist. An “open” is really a point when a connection should exist but will not. These faults has to be corrected ahead of the PCB is assembled. Unfortunately, some rigid flex circuits usually do not test their boards before they are shipped, which can cause problems at the customer’s location. So, quality testing is a critical process of the PCB fabrication process. Testing ensures the PCB boards are in proper working condition just before component placement.