Three Important Steps To Follow During PCB Assembly

Three Important Steps To Follow During PCB Assembly

Now, electronic products are everything. As the heart of all our electronics, PCB lets them run as expected. Therefore, electronics companies must understand and anticipate the needs of consumers to develop boards and products that customers satisfy. Although most consumers will never put a second on the board running their devices, this is arguably the most important part of product development. Do you know what the design and assembly of your board is? What’s the key to PCB Assembly? We’ll explore the answers in this blog today.

PCB Assembly Process

PCB assembly combines circuit boards with other electronic components to be embedded in a product. Now we will delve into the PCB Assembly Process:

PCB Assembly Process

Component selection

The first step in the PCBA assembly process is to select the electronic components based on the schematic and Bill of Materials (BOM). The BOM provides a detailed list of components required for the specific design. It includes information such as part numbers, quantities, and reference designators.

Solder paste

The solder paste itself consists of metallic solder. The components of the solder are silver, copper, and tin, and the solder paste is mixed with flux. The technician can apply solder paste to specific areas of the final printed circuit board where components are located.

Component placement

The next step is to place the components on the PCB board. If there are SMD components in the design of the PCB board, it is common to start with the SMD components.

Component placement SMT VS THT


SMT is known as Surface Mount or Surface Mount Technology and is one of the most popular technologies in the electronics assembly industry today. When we assemble using a technology like SMT, we will use the Automated PCB assembly and reflow soldering:

Automated PCB Assembly

The entire process of automated PCB assembly is computer-controlled and involves robots picking up components and placing them on the board according to the design file. The automated PCB assembly process is faster and more accurate than manual assembly and is suitable for mass production. PCB assembly today is mainly done by machines. Automated PCB assembly machines include placement machines, solder paste machines, reflow ovens, and more.

Reflow soldering

Reflow soldering involves heating the PCB assembly to a specific temperature that melts the solder paste and creates reliable electrical connections between the components and the PCB. The temperature and time of the reflow soldering must be controlled carefully, as too high or too low can damage the components or the PCB. This step ensures that the solder joints are formed properly and provide robust electrical connections.


Through-hole technology is where components are inserted onto a circuit board and then soldered in place. When we assemble by THT, we will use Manual PCB Assembly and Wave soldering.

Manual PCB Assembly

Manual PCB assembly saves technicians from manually placing components on a PCB. However, manual methods are slower and more prone to error than automated assembly. So manual assembly is mainly used in a few PCB assemblies, such as prototypes, or small PCBA with only a few components.

Wave soldering

Wave soldering lets the soldering surface of the plug-in board directly contact with high-temperature liquid tin to achieve the purpose of soldering, its high-temperature liquid tin maintains a slanting surface, and by a special device to make the liquid tin to form a wave-like phenomenon.

Quality control and testing

Once the soldering process is complete, the PCBs are subjected to quality control and inspection. This is to ensure that they are assembled correctly and meet all specifications. Inspection can be done manually or using an automated optical inspection (AOI) or X-ray inspection machine.

PCBA Functional Test

After the PCB has been assembled and inspected, it is tested for functionality. This is done to ensure that the PCB works properly in its intended application and environment. During this test, the electrical characteristics of the PCB assembly (PCBA) are measured and compared to specifications. Rise or Fall Time of Voltage and current will indicate abnormal device function.

PCBA Functional Test


After functional testing, the PCB is cleaned to remove any residual flux or other contaminants.


The final step in the PCB assembly process is to package the PCB for shipment to the customer. The packaging must also meet the requirements of the mode of transportation used.

Three important tips for PCB Assembly

As mentioned above, the PCB Assembly Process is significant for our electronic products. Here are some essential tips for your assembling:

Design and testing

PCB design is the roadmap for the entire project. Without proper design, there will eventually be secondary equipment that does not meet consumer demand, and these devices will not operate as expected or required. For this reason, it’s critical for the design process.Some companies like to listen to customer needs and create their circuit diagrams from scratch. Others tend to pass these requirements to contract design and manufacturing services for help. In either case, you need to pay the most attention to detail. At this stage, you can decide which components and components you need, how to install and arrange them on the board, and how they work together. This will determine productivity and efficiency, as well as its size constraints. For best results, we recommend that you get suggestions from industry professionals, who may find any problem areas and make improvements.Furthermore, testing should also be done to ensure that production does not occur on inappropriate equipment.

The most advanced technology

The latest and most advanced technology for assembling circuit boards is required if we are to stand up to the competition. Manufacturing smaller, more compact but still dense circuit boards requires advanced machinery.
Please do not hesitate to contact FC, as we have the high-end technology and equipment to satisfy you!

Troubleshooting and repair

Your contract manufacturer should be able to troubleshoot any potential problem and then make the necessary repairs, rather than simply throwing away faulty equipment. Not only is this more cost-effective, but it also boosts consumer confidence because you can ensure the overall integrity of the board by simply replacing or repairing the necessary components. After all, PCB assembly requires great concentration and attention to detail. Whether the final product is complex or simple, the circuit board must be carefully crafted to exact specifications. Knowing and understanding all the necessary steps is critical to ensuring your electronics are in the best possible condition.
Welcome to contact your reliable PCBA partner FC, we have three steps above to ensure PCB Assembly success.

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