Techniques Are Used in Manufacturing Printed Circuit Boards
Printed circuit board fabrication is the multi-stage process of taking your PCB design from concept to final product. In order to make high-quality, top-notch electronics it is important that all stages of the PCB fabrication process are done correctly and without error. To that end, it is vital to understand the relationship between the different fabrication techniques used in manufacturing printed circuit boards.
The first step in the PCB fabrication process is schematic capture. In this stage, a graphical representation of the components and connections of your PCB is captured in a computer-aided schematic design (CAD) software program. The resulting schematics can then be used for simulation and testing purposes.
Once a solid schematic has been created, it is time to start the actual construction of the circuit board itself. To do this, the copper layer is exposed to a photoresist material. The photoresist material, which is also a kind of film, blocks out the copper areas that you do not want in your finished circuit board. Once the photoresist has been exposed and hardened with UV light, the remaining copper area is etched away with chemicals, leaving only the pattern of copper that you wanted on your finished product. The etching process also shapes the circuit traces and pads on the outer layers of your finished printed circuit board assembly.
What Fabrication Techniques Are Used in Manufacturing Printed Circuit Boards?
Next, the PCB must be prepped and then plated. This is where the different fabrication techniques begin to really come into play. For example, a copper plating process increases the conductivity of the copper that will carry current from component to component. This is a crucial step in making sure your finished product has good connections. A finishing process known as solder mask is applied and cured with UV light to protect the copper from high-temperature solder, conductors that can short-circuit your circuit board, and environmental exposure. Finally, the board must be silk-screened with component reference designators and ratings to help in assembly and troubleshooting.
If you have a two-layer circuit board, the drilling process can begin at this point. Otherwise, the board will be sent to a printing and imaging facility where a solder mask is printed on the surface of the board. In the meantime, a technician will inspect the bare copper to make sure that all the resist has been removed and that the copper that will emerge in your finished product is correct. This is the time to correct any errors in your circuit board before it is too late.
After the printing and imaging is complete, the PCB will be moved on to the assembly stage where the components are placed on the board. Depending on the type of electronic device you are designing, this can be either through-hole or surface mount technology. Surface mount technology is a faster, more precise method of assembly that utilizes a machine to place components onto the circuit board.
Once the components have been properly placed, the entire circuit board will be run through a reflow oven. This is a heated chamber that melts the solder paste and joins the component and the circuit board together. The reflow oven is crucial in making sure the components are securely attached to the board and that no errors were made during the assembly process.