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What's Going on in the Electronic Assembly? Answer's Here


Thur, Oct 22, 2020

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In general, an electronic assembly showcases a number of electronic components (integrated circuits or elements) that are connected together in order to perform one or several specific functions. Components on the board are connected and they can be replaced or disassembled. It is capable of being disassembled and replaced as an entity. 

Electronic assembly or also called the  printed circuit board (PCB)assembly finds application in almost every piece of technology that surrounds us in our daily lives. For instance, an end design of an electronic assembly is used in your smartphone, in your pocket, or any desktop computer. Most people can easily recognize a printed circuit board when they see it. In this article, we will review the whole assembly process, so make sure to stick around.

Part 1: The Process of the Electronic Assembly

The electronic assembly is a process of mounting electronic devices on a printed circuit board. Even the  most advancedboard will not be able to deliver functionality unless it has electronic components mounted on it. The mounted circuit boards are called assembled PCBs and the process of manufacturing is called the PCB assembly or simply PCBA.

There are several main stages in the electronic or PCB assembly. The process includes inserting solder paste onto the board, component placement, test, and inspection. These four stages of electronic assembly are the main stages required for the production of a high-quality entity. They have to be executed one after another in a specific order and the leaders in that field of work are using the latest surface mount technology that we will review on its own later in this article. First, we will review the four main steps in electronic assembly to a printed circuit board.

Solder Paste

Extreme precision is required for this process, as solder paste needs to be applied to those areas of the printed circuit board where are the components pads. A solder screen is used to achieve such insertion while a runner is moving across the screen and squeezing solder paste through the holes onto the board. The amount of solder has to be exactly as necessary and the whole process is done in a controlled environment.

solder paste

Component Mounting - Pick & Place

Once the solder paste is inserted onto the board, the pick and place process is starting. During this stage, a machine equipped with all the components is placing them at their right spots on the printed circuit board. The tension of the solder paste is keeping the components in place. Every printed circuit board has its own design information that is later provided to the pick and place machine, which executes with extreme precision.

During other assembly processes, for example, the pick and place machine is squirting a very small amount of glue to secure the position of the components, but this is only done whenever the board is to be wave soldered. The method with the glue is not preferred over the traditional way due to the difficulties that may occur in case of requested repair, even though the glue should degrade during the soldering process.


Now, when the components are added to the board, the next step of the electronic assembly is the production process on the soldering machine. As we already mentioned, the wave assembly processes do not pass through the soldering machine, this process is not preferred for surface mount components. However, in these cases, the solder is provided by the wave soldering machine, but reflow soldering is the method that most assemblers go with these days.


After the soldering process, high-end manufacturers such as PCBONLINE always pass their board for inspection. However, manual inspection is not a reliable way for the surface mount boards, instead, an automatic optical inspection is performed, in which there is much more clarity in the micro-level of possible failures. The machines that are executing the inspection stage are designed to locate faulty components, bad soldering, and any perspective for malfunctioning.

inspection machine


This is one of the most important objectives in the process. It is extremely important for the PCB manufacturers to test their entities after the electronic assembly process. There are a series of durability and stress tests before a PCB can exit the assembly process, such as flying tube tests, in-circuit tests, functional tests, etc. Quality and reliability are mandatory when it comes to PCB assembly due to the damage that a faulty PCB can cause to a certain industry.


During and after the process of electronic assembly, the input and output of the printed circuit board are monitored in order to ensure the rightful execution of its duties. Many failures and malfunctions are detected via this method and the issues are resolved in the early stages that are preventing further complications. The perfect place for a feedback test is right after the soldering process because this is the part in which most of the issues are occurring. This way the defect is detected quickly and resolved before the next step of the assembly process.

Have in mind that the process of the electronic assembly is simplified as an overview in this article and there are a lot more details that are taken under consideration by manufacturers when assembling printed circuit boards. High-end developers are using optimized methods in which the cases of failure are minimal and the quality is a top priority.

Part 2: Techniques We Use in Electronic Assembly

The process of electronic or PCB assembly includes several different approaches, including SMT, THT, and DIP. We will take a look at each of them with a basic overview.

SMT - Surface-Mount Technology

As we discussed earlier, SMT, surface-mount technology is a method in which the electrical components are mounted onto the surface of the printed circuit board (PCB). The component itself is mounted in an action referred to as a surface-mount device (SMD) with an SMT stencil. SMT is the latest and widely used electronic assembly approach because complete automatization with this process is possible. This remarkable technology reduces the cost and increases the quality of the assembly, which makes the preferred method over Through-Hole Technology (THT). The electronic components of SMT are often smaller than its through-hole competitors because in most cases they don’t have leads and even if they have, they are smaller.


THT - Through-Hole Technology

Through-hole technology is another mounting scheme, used mainly for electronic components. This method is using leads on the components that are inserted through the holes, pre-drilled on the printed circuit board. The pads on the opposite side are soldered either by insertion mount machines or by hand. The innovation of the through-hole technology replaces many earlier electronic assembly approaches. Invented in the 1950s, slowly growing until the 1980s when it became the main process that high-profile manufacturers are using. Unfortunately, this method was later replaced with the innovation of the surface mount technology. However, many manufacturers still use this technology for projects demanding through-hole methods.

DIP - Dual-In-Line Package

A Dual-in-line package (DIP) or also dual-in-line pin package (DIPP), is a package of electronic components with two parallel rows of connecting pins with rectangular housing. For instance, the electronic package of components could be inserted in a pocket or through-hole mounted to the printed circuit board. The DIP is often showcased as DIPn, where the “n” is the number of pins. For example, a microcircuit with two rows of five vertical leads would be a DIP10. This technology was invented in 1963 by Don Forbes, Bryant Rogers, and Rex Rice at the Fairchild R&D.

Part 3: Best Electronic Assembly Services Are Here

If you are looking for reliable PCB manufacturing with high standards and quality of work, PCBONLINE is a global electronic group with 20+ years of experience in PCB fabrication, assembly, and EMS solutions. They have a world-leading quality management system, focusing on advanced PCB manufacturing and assembly. This is the best physical and online retailer with the lowest prices on the market.

With their years of experience, PCBONLINE has become a large technology-oriented team with 60+ software developers, 45+ member hardware department, and 500+ senior technical engineers. They have fully automatic intelligent equipment and an independent developing team, constantly investing in R&D and technical training.

Their innovative workflow includes IMS intelligent manufacturing system, SCM in time delivery, and traceability to ensure product quality and lean manufacturing. Make sure to check many positive testimonials from clients on their  feedback page and many informative and interesting articles and guides in their  blogs. If you are interested, they provide an online quote option for free, so if you have any concerns or inquiries, make sure to get a quote on their website.


High-end PCB assembly manufacturer delivering customizable solutions and good quality. Here are some of the efficient options when working with PCBONLINE.

  • Low Volume PCB Assembly- One of the most advanced solutions provided by PCBONLINE. It is referring to 5 to 2,000 pieces that require soldering parts on. It is one quick and reliable way with electronic samples production and testing. This is an optimal solution with a quick turnaround and a small volume.
  • High Volume PCB Assembly- You can have both, consigned high-volume PCB assembly and turnkey service. If the demand is more than 10,000 pieces of PCB to be assembled then this is the workaround for you. It includes soldering components, SMT stencils, AOI inspection, DFT checking, and more.
  • Consigned PCB Assembly- Again we have both partial and full consigned assembly service. As a trustworthy complex consigned PCB assembler, PCBONLINE provides optimal solutions, regardless if you have the parts of a bare printed circuit board.
  • Turnkey PCB Assembly- This is a process that enables you to complete assembly and manufacturing in one place. If time is a valuable resource to you, the turnkey PCB assembly is the optimal solution, as you don’t need to worry about anything. One-stop PCB service is designed to provide reliable components, full assembly, and delivery packaging. The turnkey PCB assembly involves all possible steps that certain projects might require. Starting from the fabrication to the assembly process passing through all necessary details covering every aspect and delivering high standards.

Part 4: What Does an Electronic Assembler Do?

The electronic assembler has a wide range of meanings depending on your duties. You could be assembling electronic parts such as circuit boards, mounting them into larger assemblies or casings. Electronic assemblers also ensure that the installation and soldering are properly performed as well as electric wiring. As an electronic assembler, you might be even troubleshooting equipment in case it is returned to service or failed.

With the innovation of electronic components, they have become smaller and smaller. Most of the processes are one with automatization equipment which requires a human touch to perform as per the requirements. As an electronic assembler, you will need to have excellent knowledge of the equipment responsible for the major electronic assembly. The assembler’s duties are depending on the field of work and focus area. One thing is for certain, electronic assemblers have extreme dedication and precision towards outstanding quality in production.

Bottom Line

In general, when most people hear of electronic assembly putten this way, they are referring to a collection of electronic parts assembled together into a larger unit. As we already discussed in this article electronic assembly would be printed circuit board and the implementation of electronic components via technical processes with substages. Electronic Manufacturing Services - (EMS) is another way that we could describe electronic assembly including design, development, test, distribution, and repair services.

Keep in mind that the process is far more complicated than in this overview. There are many details and complex issues that are occurring during the process of electronic assembly, which suppliers are optimizing every day towards a lower volume of failure. Now when you have a general idea of what’s going on with the electronics assembly, you might be wondering " How Can I Find A Good PCB Supplier". If this article was interesting to you and you want to find out more about electronic assembly, make sure to check the" What Do You Need to Know About Turnkey PCB Assembly and EMS?