What is Printed Circuit Assembly?
Printed Circuit Assembly
Printed circuit assembly, also known as PCB assembly, is the process of placing components and soldering them to a PCB. This can be done either manually or with the use of automated machinery. The manual process is called traditional hot-melt (THT) and the automated process is called surface mount technology (SMT).
To produce a printed circuit board, a copper layer is added to an insulating substrate. This can be a single side of a non-conductive material, such as FR-4 glass epoxy or phenolic cotton paper impregnated with phenolic resin; or double-sided, where the copper is added to both sides. Then a pattern is etched into the copper using a photoresist coating that is exposed to light in the pattern of the desired design. The resulting etching removes the unneeded copper and leaves behind a pattern that can be duplicated. The substrate is then coated with a layer of polytetrafluoroethylene, or Teflon, that provides additional insulation and resists corrosion.
The next step in the printed circuit assembly manufacturing process is applying a solder paste. This is similar to screen-printing a shirt, but on a larger scale. Assemblers place a stainless-steel stencil over the PCB to apply the paste in the intended areas of the finished circuit board. The applicator then spreads the paste evenly across the stencil. After the stencil is removed, the solder paste remains only in the intended locations on the finished PCB, where it will bond with components.
What is Printed Circuit Assembly?
Once the solder paste has been applied, the next step is component placement. This can be done manually, with a pair of tweezers, or automatically, with the help of machines called pick and place machines. For THT, the tweezers are used, but for SMT, this is usually a robotic process that eliminates human error and fatigue, allowing the production line to run around-the-clock.
After the components have been placed, the boards are sent through reflow soldering, where they go into an oven that heats the solder, melting it and ensuring all connections are made correctly. This is done before the board goes into a series of coolers to cool the solder and cement the components in place.
Upon completion of the soldering and inspection steps, the resulting board is tested for function. This can be done with a visual inspection, or with the aid of a tool that checks for errors in the design and manufacturing processes. If a mistake is detected, it can be corrected before the next batch of boards is produced, saving time and money for all parties involved.
Whether you need a basic printed circuit board to test a new prototype, or a complex electronic device, a professional PCB manufacturer can meet your needs with fast, accurate, and cost-effective service. Contact us to discuss your requirements and receive a quote. We look forward to hearing from you!