PCBs Manufactured
A printed circuit board is the mechanical and electrical backbone of a wide variety of electronic devices. It connects components through conductive pathways and signal traces on copper sheets laminated onto a non-conductive substrate. From household appliances to high-tech machines, PCBs enable the functionality of an array of electronic devices.
pcb design, fabrication and assembly is a complex process with many interconnecting stages. To prevent errors that can result in short circuits or incomplete circuits, strict quality control standards are applied throughout each stage of the process. This includes visual inspection and a comprehensive battery of tests and assessments.
The PCB fabrication process begins with a design blueprint. The schematic design outlines the layout of the board’s components and their interconnections. The blueprint is created using computer-based software programs, the most commonly used of which is called Extended Gerber.
How Are PCBs Manufactured?
Once the PCB design has been green-lit, the fabrication process can begin. First, the base material for the circuit board is fabricated from a combination of woven glass fibre and epoxy resin. The materials are then semi-cured in an oven and cut into panels. These panels are layered together with adhesive copper foil, and the layers are bonded together under high temperatures.
Next, the PCB receives its outer layer imaging. A photoresist is applied to the copper surfaces of the PCB, with black ink preventing light from penetrating areas that are meant to remain as pathways. Then, an ultraviolet light is applied to the circuit board. The UV light passes through the translucent photoresist and hardens those sections that are meant to remain pathways. This also erases any mistakes that may have been made in the earlier image scanning stage.
The final imaging step involves the application of solder masks and silkscreen. The solder masks protect the copper surface of the circuit board from damage during the soldering and assembly stages. The silkscreen, on the other hand, is used to print text and images that serve as a guide for assemblers and facilitate quality control.
After the outer layer imaging and component placement steps, the assembly dance begins. Automated pick-and-place machines, equipped with vacuum nozzles and precision robotic arms, delicately place the components on the PCB. The machines are programmed with the component placement data, ensuring that each piece finds its designated spot on the board. Once the components are in place, the assembly moves on to the soldering stage. During this phase, a metal alloy known as solder undergoes its transformation from solid to molten, establishing a robust and reliable connection between the components and the PCB.
Wave soldering caters to through-hole components, while reflow soldering serves the needs of surface-mount components. Both soldering methods require a precise choreography to ensure that the components and the PCB are seamlessly joined. Once the soldering dance is complete, the assembled boards are inspected and tested to verify that they comply with the specified performance and reliability standards. If all tests are passed, the PCB is ready for shipment to its final destination.