The Assembly of PCBs

The Assembly of PCBs
4 min read
26 December 2022

The PCB assembly process can be viewed as a collection of steps used in the construction of electrical devices. It entails pick-and-place, reflow, and wave soldering. Every single one of these procedures is essential to the creation of an electrical device.

Soldering by reflow

During PCB assembly, reflow soldering is used to create sturdy joints for the components. It entails a number of crucial actions.

Components are positioned over solder paste and fastened using surface tension during this procedure. A solder joint is created when the solder paste melts at a high temperature and then solidifies. To avoid heat shock to the components, this junction is then cooled.

In order to facilitate the combination of solder powder spheres and reduce surface tension at metal junctions, flux is additionally applied to the board. A metallurgical connection is also facilitated by flux.

The flux is then used to lower the surface tension before melting the solder powder at a higher temperature. This enables the flow of the solder alloy. The joins will solidify during the cooling process to provide a sturdy solder joint.

The principal hydrocarbon utilised in the reflow process determines the maximum temperature permitted within the oven. The joints may become damaged or inefficient if the procedure is not carried out correctly.

The Assembly of PCBs

soldering in waves

Wave soldering is a method for putting together PCB boards. It is a highly quick and effective method of board assembly. However, there are several considerations to do in order to guarantee the finest outcomes.

Prior to beginning the wave soldering procedure, it is crucial to pre-heat the PCB board to the appropriate temperature. Inadequate solder thickness and mechanical stress on the board can result from the inappropriate temperature.

Make sure the board has the appropriate quantity of flux applied to it as well. If there is too much of it, the board may develop voids and other flaws. Additionally, it can accelerate the PCB's long-term deterioration.

There are numerous varieties of soldering methods available. Reflow soldering and wave soldering are examples of this. They are all utilised to affix electronic parts to the board. The time and temperature requirements for each approach, however, are different.

a pick-and-place device

Pick and place equipment plays a critical role in PCB assembly. They allow a more precise location and are used to insert components onto the board.

Manual and semi-automatic pick and place devices are both available. The manual version is intended to increase yield while reducing operator fatigue. This kind of device features a head that is supported by an arm and is run by software. An unattended manual model can be set up for high-speed operation.

Positioning accuracy is crucial for small components. The component is moved by the machine's head using a suction to guarantee precise installation. The pick and place machine dispenses a liquid, typically solder paste, and temporarily adheres the component to the PCB while the vacuum is operating.

The pick and place device also has a fluid dispensing system and a nozzle that pours glue or other substances. For prototypes and one-off PCB assembly, these systems are crucial.

The Assembly of PCBs


A critical stage in the creation of printed circuit boards is PCB inspection. You can use it to check for flaws or alignment issues that might impair your product's performance. Short circuits and malfunctions may result from these flaws.

Inspections can take many different forms. Both human and automatic inspections are part of them. Choose an inspection technique that will guarantee the PCB's integrity. You won't have to deal with a faulty board if you select the proper approach.

The cost of manual inspection techniques is high. They do, however, let you see a thorough overview of the PCB. Five joints can be inspected by certain inspectors every second. This implies that a PCB inspection can be completed quickly by a knowledgeable specialist.

An enhanced visual inspection method is automated optical inspection. It can identify flaws like open solder junctions using an optical method.

Another useful technique for evaluating the quality of your PCB's components is x-ray inspection. Additionally, it can spot erroneous or missing connections.


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NextPCB is one of the most experienced PCB manufacturers in Global, has specialized in the PCB and assembly industry for over 15 years. Not only could NextPCB p...
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