Understanding PCB Assembly

Electronic components must be assembled to form printed circuit board assembly or functional printed circuit assembly once the Printed Circuit Board (PCB) is complete. This process is known as PCB assembly. A multiple step process, PCB assembly includes through -hole technology and surface mount technology (SMT). The requirements for PCB assembly include knowledge of PCB components and assembly as well as the knowledge of the printed circuit board design. Furthermore, you must have a strong understanding of PCB fabrication and the final product.

Component leads are soldered through a wave soldering process after they’re place onto the board in through-hole assembly. You can use the wave soldering process to solder some SMT components after placing them on the bottom side of the board. In source mount technology process, components are placed on the connection pads of the PCB after the pads are solder-pasted. In order to electrically and mechanically connect the component leads to the PCB, the solder paste is melted in a reflow furnace.
If you want to deliver the perfect product the first time, you must consider the assembly of PCB as a critical part of PCB fabrication and important piece of the puzzle. Thanks to their close-knit design, PCBs are easy to install and repair. However, you will only benefit from PCB installation if you assemble a printed circuit board accurately. Following are the assembly steps in PCB fabrication:

Choose the PCB technology

In order to assemble PCB, the first thing you need to do is choose the assembly technology. This means that you need to choose between through-hole technology, surface mount technology and mixed technology. You can move onto the rest of the assembly process once you’ve chosen the technology.

Solder the components onto the board

The second step in the assembly process is soldering the components onto the board. Attach the electronic components to the printed wiring board using a tin or lead solder.

Attach the components

A schematic patter or drawing is what you’ll find on the circuit board. Using a machine loaded with component reels, the components need to be picked and placed onto the correct position on the board. The tension of the solder place holds the components placed onto the board. Provided the board isn’t jolted, this is enough to keep them in place.

Pass through Soldering machine

The design of the soldering machine allows all the components to be properly affixed on the circuit board. Furthermore, it prepares the printed circuit board for the next step in the assembly process. Because the solder is provided by the wave soldering machine, solder paste isn’t added to the board when wave soldering is used.

Inspect

Inspect the board after it has been passed through the soldering process. For surface mount PCBs, manual inspection isn’t an option. Instead, machines are used for this purpose. Automated inspection machines are commonly used to inspect main PCB assembly for quality control.

Test for defects

The final step in the assembly process is testing the PCB for defects. Automated Optical Inspection (AOI) is the most commonly used process for inspecting and testing printed circuit boards. The AOI machines check for loose components, over-soldering on the circuit board, loose joint, etc.