Everything You Need To Know About Types Of PCB Assembly

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PCB assembly technologies widely serve different departments like industries, the army, and space. The experts are using different types of PCB assembly technology to bring about reforms and new inventions in the world. As it is very clear for almost all devices, we need the PCB and different types of PCB assembly to get into the completion of the world.

We will not live without these little magical boards in the next coming decades. PCB assembly processes serve extraordinary procedures in different working fields. If we generally talk about the process of PCB assembly, it includes some automated and some manual steps to get complete construction.

Types of PCB assembly you need to know about

While preparing the PCB assembly, the experts use different techniques to assemble the PCBs and other electrical components on a single board. They use different materials and techniques to make different amazing circuits to supply different amounts of current to the devices. Here, we shall discuss three main types of PCB assembly by discussing their different parameters or features, advantages, and disadvantages.

Surface mount assembly technology.

One of the most common types of PCB assembly technology is surface mount assembly or SMT. In this type of PCB assembly, the experts use printed boards for mounting the PCBs and other electrical components to complete a circuit. The manufacturers use solder paste for mounting the components on the printed surface of the board.


Surface mount assembly is a PCB assembly technique consisting of three basic and distinct steps other than the basic steps. So, during SMT, the experts follow the steps.

  • Solder paste printing

For creating a circuit, the experts prepare a board for printing and pasting the solder paste through a solder paste printer. Solder paste printing helps the designer with the theme he needs to follow for creating the circuit. A printed solder screen is responsible for solder pasting accurately at the right place where you feel you want to mount the components.

  • Picking and placing components

After painting or placing the solder paste on the board for making the printed paths to follow, it is time to go for picking and placing the components. The automated machines will start mounting the components of the circuit, including the PCBs on the solder pasted board. The automated machines choose the right position for the components. So, you may say the past solder print was the map for mounting the components.

  • Reflowing solder

Every component of the PCB assembly is in its right place, but do you think it will be there permanently? It is possible only when the manufacturer reflows the circuit by passing it through high temperatures. When you pass it through high temperature, the solder melts and makes joints with the board and components. It helps the circuit to keep every component in the right place after cooling.


SMT is one of the best PCB assembly technologies that tends to bring you many advantages, some of which are as follows.

  • Design flexibility

Surface mount assembly comes with a flexible design which means there is no restriction of design to follow every time. The design of this circuit is quite flexible and can be adjusted as per need.

  • Stability 

Due to soldering paste, the circuit components get a strong connection with one another for a longer time. Now, the stability of the circuit increases and will remain for a longer time.

  • Automated fabrication

You do not need to do mounting with your hands during SMT, but the automated machine will do everything. An automated machine will pick and place the components.

  • Best performance in every condition

Surface mount assembly will work brilliantly no matter in which condition you are using it. It is suitable for all weather conditions and can resist harsh conditions.


Like other things, SMT also has some disadvantages over all these advantages. Some disadvantages are as follows.

  • Not reliable

Surface mount assembly is not reliable due to its paste print on the board that can get damaged with time and cause a cut of the current supply.

  • Low surface area

The components used in this assembly are usually of small size, so the surface area is very small for some complex processes.

  • Complex

Everyone cannot use it easily, but experts can.

PCB assembly


  • You will find wide uses of SMT assembly.
  • We use SMT in medical devices.
  • Scientists use SM in aerospace systems.
  • SMT is also useful in defense systems

Through-Hole assembly technology

The most ancient of all types of PCB assembly technologies is Through-Hole assembly technology which was launched first in the 1950s. Later, SMT took charge of it in the 1980s after the invention of the computer. Through-Hole assembly is much famous among the people still now.


The experts or even new designers, while working on making Through-Hole assembly technology, have to go through the following steps.

  • Placement of PCBA components

The placement of the PCB assembly component is a different form than the other two types of PCB assembly technologies. In the other two types of PCB assembly technologies, the automated machines serve this step. In the case of through-hole PCB assembly, the engineers do the placement of components of PCBAs by using their hands and little tools like tweezers.

  • Inspection or quality checking

After placement of the components of the PCBA, the engineers look for the inspection of This PCB assembly. In this process, the matching board will help to recognize whether the board is in the right position or not. In this step, the experts check whether everything is in the right place or not, and it's an automated process.

  • Wave soldering

In this step, the Through-Hole assembly is passed through the wave of a high temperature of about 500 Fahrenheit. This temperature will surely enhance the soldering of the assembly and make it reliable for a longer time.


Here are some advantages of the through-hole assembly technology that you need to know.

  • Reliable

No doubt, this type of PCB assembly technology is ancient, but it is still reliable as the components used are soldered perfectly. These are good enough for long-running.

  • Easy to use manually

This type of PCB assembly is not made automated and has distance among the components of the PCB assembly so that you can manually use it. The composition of this type of assembly is quite simple, and even new users can easily use it.

  • Durable

The soldering of this PCB assembly is quite good and solid enough.  

  • Easy testing process

It is easy to test whether the components are placed in the right positions just by matching the transport frame.


  • Not suitable for multilayered PCB

It is so simple in composition and has smaller PCBs; that's why not suitable for multilayer PCBs.


  • It is used in smartphones
  • It is used in LED light.

Mixed PCB assembly technology

Mixed PCB assembly is the most powerful and widely used technology as it consists of two types of PCB assembly technologies. It uses SMT and THT both for developing any kind of mixed PB technology. To understand mixing PCB assembly, the following information helps you.


When we talk about mixed PCB assembly, we come to know that it consists of two types of PCB assembly technologies. Mixed PCB assembly technology can follow any of the following conditions.

  • Single-sided

This type of mixed PCB assembly has only one type of assembly, which is usually SMT which may have a little amount of THT assembly. In this type of mixed PCB assembly, there is very little amount of Through-Hole PCB assembly. So, there is no need to add adhesive in between them. So, it is the cheapest of the other two types of mixed PCB assembly.

  • Double-sided

With double-sided mixed PCB assembly, you will observe two alternatives, one with adhesive and the other without adhesive. Double-sided mixed assembly with adhesive needs three sessions of heating process for proper composition.

  • SMT on one side and THT on another side

The third type or condition of mixed PCB assembly is one side with SMT and the other with THT. Both other basic types of PCB assembly technologies are jumbled in this condition. For connecting these two PCB assemblies, adhesives are required.


  • Feature of both SMT and THT PCB assemblies
  • Have different types
  • Testable by X-ray detection


  • Soldering issue

As the adhesive is added to the mixed PCB assembly technology, it can cause soldering issues that may lead to low stability.

  • Low efficiency

Due to the addition of adhesive and more than one type of PCB assembly technology, the mixed PCB assembly will go through three more heating processes. This increase in heating will decrease the efficiency of the mixed PCB assembly.

  • Expensive

As Mixed PCB assembly requires adhesives for binding SMT and THT, so it enhances the cost-effectiveness of the process.


  • Mixed PCB assembly aids in video processing
  • It is also available on CPUs
  • You are going to use it on smartphones
  • Communication devices like computers, phones, radar, etc., can have Mixed PCB assembly.
  • It is present in LEDs lights
  • Server boarders


These are the types of PCB assembly and a guide to their technical information.  You can get to know where you need to use it.


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