While making PCBAs is a fun task, learning how the brains of all electronics are created offers joy and a sense of accomplishment. Each step of the assembling process is carefully thought out to produce a board that works flawlessly. Additionally, as electronics become more sophisticated, PCB manufacturing equipment is increasing and becoming more fascinating than ever.
Solder Paste Printing Machine
Solder paste is applied to the board as the initial step in PCB assembly. Usually composed of tin, lead, and silver alloys, solder paste is a grey-coloured goo formed from a combination of very microscopic metal particles. Consider it as the glue holding your finished board together. Components wouldn’t adhere to your bare board without it.
The PCB is covered with a stencil before the paste is applied. A PCB stencil is a piece of stainless steel with tiny laser-cut holes that allows solder paste only to be applied to the SMD pads, which are the board parts where the component connections will eventually be located on the finished PCB.
Glue Dispensing Machine
The glue dispensing machine uses glue dots on the PCB before component insertion to hold the component bodies until the leads and contacts are connected. This is crucial for reflow soldering or double-sided wave to prevent component drop-off and wave soldering, where the force of the solder wave may remove bigger components.
Reflow Soldering Machine
The most used soldering method for PCB assembly is reflow soldering. The assembly is transported via a conveyor via a lengthy, enormous oven called the reflow soldering machine once the board has been fully populated with components. As the PCB boards move through several temperature-controlled zones, the solder paste melts and steadily hardens to make reliable electrical connections between the component pads and their corresponding components.
The circuit board is moved along a conveyor system through the equipment’s various temperature zones. The solder paste is dried, heated, melted, wetted, and chilled before the components are soldered to the printed circuit board. The main component of reflow soldering is using an external heat source to heat the solder, causing it to melt, flow, and re-infiltrate the circuit board.
Automated Optical Inspection (AOI)
The boards have now been assembled, and testing and inspection are next. Automatic visual inspection is more crucial than ever due to the rise in the complexity of PCB boards. Even though you can still try to use your naked eyes to discover errors, manual inspection is ineffective for mass production since workers quickly become worn out, and errors are more likely to be overlooked. Testing PCBAs is essential in PCBA manufacture to prevent expensive re-manufacturing costs and material waste. AOI systems identify issues early in the production cycle, allowing for the modification of methods or the correction of specific boards.
AOI systems can complete tests formerly done by humans but much more quickly and accurately by using optical technologies to detect errors. The AOI machine uses high-resolution cameras to capture the board’s surface and create an image for analysis.
Functional Validation Test (FVT)
Before shipment, completed PCBs must pass Functional Validation Testing (FVT), which is the last phase. We are no longer merely looking for physical flaws like solder bridges or tombstones. The board is instead loaded with software, and we are testing to see if it will function when utilised in whatever application our customers have in mind.
Likely, components won’t be manually soldered when many PCBs need to be created. Expert assembly companies steps in to assist with the fabrication of both the bare boards and the assembly of all the parts into the Printed Circuit Boards, or PCBs.