Circuit Board Assembler – What Is It?
Circuit Board Assembler
A printed circuit board (PCB) contains conductive pathways that connect components and turn it into a functional electronic device. A circuit board assembler is the person who attaches those components to the PCB to create an operational circuit. The assembly process involves multiple steps that can be categorized into pre-assembly, during assembly, and final assembly. Depending on the type of circuit board being assembled, the steps may differ between Surface Mount Technology (SMT), Through-Hole Technology (THT), and Mixed Technology. Choosing the correct assembly process depends on the design layout, space constraints, and production volume of the resulting circuit board.
The first step in a circuit board assembly job is applying solder paste. This is done by a stencil, a thin layer of stainless steel or other durable material that matches the PCB layout and has openings corresponding to where components will sit on the finished circuit board. The stencil is affixed to the PCB, then a squeegee, a metal or plastic blade, is used to spread the paste evenly over the area of the board that will contain components.
After the solder paste is applied, it must be inspected to ensure that the paste was placed properly. This can be done manually, or with an automated inspection system. Looking at small components for hours on end can cause eye fatigue and inaccuracies, so automated systems are preferred in most cases.
Circuit Board Assembler – What Is It?
Once the paste has been inspected, the assembler can begin placing the components. This step can be automated, depending on the component type and size, or manual. For example, SMT machines can precisely position components with pins or other flat connections directly onto the surface of a PCB using pick-and-place technology.
For through-hole components, a hole must be drilled into the PCB. Computer-controlled drilling machines use a specialized bit coated with tungsten carbide to avoid dulling the copper in the board’s substrate. The holes can be made conductive by electroplating or inserting hollow metal eyelets. The drilled holes, along with the through-hole components, are then inserted into the PCB, and the through-hole connectors are soldered to the holes.
Circuit board assembly is a crucial process in the manufacturing of electronic devices, encompassing a series of steps to create functional electronic circuits. These circuits serve as the backbone for countless devices, ranging from smartphones and computers to medical equipment and automotive systems. The process of circuit board assembly requires precision, expertise, and advanced technology to ensure the reliability and functionality of the final product.
The next step in a circuit board assembler’s process is to pass the completed circuit board through reflow soldering, which melts the solder paste and secures the components to the substrate of the PCB. The assembly then goes through a cooling zone, which helps to prevent thermal stress and thermal damage. The reflow process is also known as “wave” soldering, because the circuit boards are passed over a molten wave of solder to complete the electrical connection between the components and the PCB. If necessary, rework can be performed at this stage to replace defective or damaged components.