SMT Manufacturing Fundamentals and the Process

SMT, is surface mount technology in full. It is the process of mounting electronic circuits on a tiny piece of components such as resistors and capacitors. One can do this in a wide variety of ways using metal layers and different solder alloys. The benefits of SMT include:

  • Lower throwaway rate
  • The lowest amount of material waste
  • Maximum use and reuse
  • Increased reliability (cheaper to fix)

The SMT process allows for the creation of smaller electronic components with less waste and lower equipment costs.

This methodology can even allow for multiple uses. It allows for recycling and repurposing the same metallic parts from previous components into a new one. Thereby freeing up resources and reducing waste. Using SMT also reduces the cost of producing a single electronic circuit over time compared to other methods. Because of these benefits, SMT is applicable in various fields. They include cell phones, computers, medical devices, and much more.

The difference between SMT and SMD

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SMD (Surface Mount Device) is a type of SMT (surface mount technology) that involves placing components on the surface of the PCB (printed circuit board).

The main difference between SMT and SMD is placing each component in its separate package with SMT. With SMD, all the components are in the same package; this allows for more economical manufacturing. Mass manufacturers mainly use this manufacturing technique for decades. They use it to supply their customers with various technologies.

The transition from SMD to SMT began in the early 1970s, with the invention of SMD. Using newer technology, it is now easier for manufacturers to produce both types of devices. It allows them to manufacture smaller electronic components that are essential in many modern technologies. It is an extremely popular process among manufacturers. This is because it helps to reduce costs and make it easier for customers to repair their products.

What is SMT manufacturing?

SMT production is the process of creating electronic circuits by plating and metal layers. One can do this with various materials such as copper, tin, lead, gold, silver, and many others. The manufacturing methodology involves:

  • SMT Plating: Plating is the process of applying a thin layer of metal to an object. It involves the following steps:
  • Cleaning: where you clean the surface to remove dirt and debris
  • Plating: where one applies a thin layer of metal such as copper
  • Drying: where one removes excess moisture, or chemical materials, from the part.

You may also use Flux material for this process. It allows the plating solution to flow smoothly and turn into a solid covering over time.

  • SMT Solder: Solder is the process of using liquid metal to place components onto electronic circuits. it involves the following steps:
  • Cleaning: where you remove any dirt or residue
  • Tinning: where you apply liquid metal solder to the component
  • Drying: where you remove the excess moisture, or chemical materials, from the part

An essential aspect of this process is using alloys in the liquid solder. These are metals that we use in the solder to make it harder or give it more strength. The alloys can include gold, tin, silver, copper, and more.

  • SMT patterning: This is the process of creating clear shapes on the circuit board for soldering purposes. One can do this through various methods, including:
  • Photolithography: where you use light to create shadows
  • Etching: where we apply chemicals to remove selected areas that are not needed

Why use SMT?

In the early days of SMT manufacturing process, it was a common perception that making a component into a fine, continuous layer would carry more current. It was the logic behind some early technologies. For example, in some cases (e.g., polysilicon), this has improved circuit density and cost/weight reduction. But, it has not improved performance or reliability. But, some modern-day aspects of SMT manufacturing depend on this logic, i.e., some modern-day photoresists have a thinner layer.

A new logic justifies using a fine layer. This logic involves maximizing the usefulness of the electronic circuits created. In other words, there is less need for discards and therefore less waste involved. Also, larger components mean one requires more manufacturing time to produce corresponding electronic circuits. In contrast, one can produce smaller components at a faster rate and with greater efficiency. It is one of the key reasons why SMT manufacturing has become so popular. Making use of its strengths can also allow for a product with greater longevity and improved performance.

The design of the circuit board, for example, is essential in SMT manufacturing. You must replace very single component correctly on it to prevent short circuits or other issues. It ensures that the entire electronic circuit works, without any errors or disruptions.

SMT manufacturing process

This technology has been useful in producing PCBs (printed circuit boards) for over 50 years. According to one estimate, it accounts for 99% of all PCBs produced. This Manufacturing Technology, has become one of the important engineering advances in the last decade.

SMT equipment

One does the assembly process using specific machines and tools, each designed for a particular purpose. Still, all necessary for the manufacturing process to complete without any defects or malfunctions in the finished product.

Examples of such machines and tools include:

  1. SMT placement equipment: You can use this to place the different components into their respective positions on the PCB.
  2. Pick and place equipment: You can use this equipment to pick up components by hand for placement onto a PCB. One can also remove them from their package and place them into position. This is before finally returning them to their original packaging. After this process, you may also need to clean some machines, while others will need calibration for any new parts that may have replaced old parts.
  3. Surface mount oven: You can use this component to remove solder and flux from the surface of a PCB. Do it in an ultra-high temperature environment, sometimes at up to 300°C, which will melt away any excess residue and allow for a clean and smooth surface. It prevents any defects or contamination from affecting the finished product.

Here is the Manufacturing Process

Material preparation and examination:

First, you must examine the board to ensure that all parts are completely in place. Also ensure that there are no damages in the process. A fine, smooth layer of copper is essential for this purpose. You then clean the boards thoroughly to remove any dirt or debris. It ensures that the entire surface is clean and void of any existing substances or residues.

Stencil preparation:

Stencils are an essential part of the SMT manufacturing process. Here is where you place all the parts of the electronic circuit onto the PCB. It includes mounting pads, resistors, capacitors, transistors, and more.

Solder paste printing:

You must apply the solder paste to the boards’ spots where you place the components. This step is typically manual. But, some production lines use robotics and automation to reduce costs and increase efficiency.


The solder paste is then pre-heated in an oven or device to remove moisture and other chemical compounds. You can typically do this process at a relatively low-temperature level. This is not to affect the electrical properties of the components themselves.

SMC placement:

Once the solder paste is in place, it is time to place the SMTs. Using a machine, you place the leads around the pads to provide connections. We make this process more efficient by the introduction of robotics and automation.

Reflow soldering:

In the most advanced production lines, you then place the SMTs inside a chamber. One uses an oven to heat all the components until they melt and fuse with the solder paste. This entire process typically takes about 5–10 seconds.


Once the solder has melted, then place the board into an oven. It heats it to the highest temperature level to completely dry all the components. This step can take anywhere from 2–5 minutes.

Finished PCB assembly:

The circuit board is then placed onto a conveyor belt to remove excess solder paste and allow full drying. Once you complete this process, you can move it over to a device that uses automated pins to push all the boards into place once you apply the welds.

Clean and inspection:

You should check the board to ensure that all components are correctly in their place and have no mistakes. It is crucial in SMT manufacturing. Because you must solder the board by hand with high-quality solder paste. You will then apply and heat it to provide a smooth and aesthetically pleasing layer of copper.

SMT contract manufacturing

There are several different types of contract manufacturers for SMT, which include:

  1. Original Equipment Manufacturers (OEM). This contract manufacturer has all the tools to manufacture the mechanical devices themselves. They use SMT to make components for their products or other companies under contract, including multipurpose suppliers. Having a global manufacturer such a RayMing PCB and Assemblywill help ensure that your product will be up to standard since you are contracting them for an assembly job.
  2. Electronics manufacturing services (EMS). Service providers do not have manufacturing facilities. But, they can supply equipment and tools to complete the job according to customer specifications.
  3. Original Design Manufacturers (ODM). ODM contract manufacturers have all the tools to make a design, including a PCB or printed circuit board, but they don’t make the components. Instead, they make the PCBs with standard components that another SMT supplier can supply for the assembly process.
  4. Component suppliers. This contract manufacturer usually has all the necessary components. But they do not have their assembly facilities. They typically have facilities used to assemble products or components. The manufacturers then ship to other companies who want to make their products.
  5. Multipurpose suppliers. Suppliers have enough equipment and supplies to make parts for mechanical devices, electronic devices, or even used equipment.

Fusion SMT

We use the term Fusion SMT to describe combining two different manufacturers to create one single manufacturing process. It means that instead of using the same tools and methods for different components, one combines them into one single production plant.

This leads to an increase in the number of companies offering SMT services to their clients. It also allows smaller companies with less resources to manufacture products without necessarily investing in their facility.

SMT assembly

When it comes to SMT assembly service, it involves many different steps. These include the following:

  1. The respective manufacturers make the parts. Then shipped to the assembly line for placement onto the printed circuit board after checking them for accuracy. One may partially assemble these parts during the shipping process. They can still require further work before you place them into position on the PCB.
  2. Once the parts arrive, someone comes to inspect them for any damage from the shipping process. They will also check for packaging errors and whether or not any components need replacement.
  3. What follows is placing the parts into position by using SMT placement equipment. It includes placing the components onto the board’s surface, removing them from their respective packages, and checking their positioning on the circuit board before finally melting down a layer of adhesive to fix them in place.
  4. The manufacturer then prepares the surface of the board using a wave soldering machine. It removes any excess solder or flux on the surface or leads to imperfections in the finished product.
  5. There is the inspection of the circuit board again for any possible defects created during placement, assembly, or soldering.
  6. Then they ship off the circuit boards to other companies for further processing and final assembly into a final product for sale on a retail level.
  7. Finally, they inspect the finished products for further defects. Such as damaged parts, damage to the packages, and malfunctions of electronic components.

Advantages of using SMT

The main advantages of using SMT are:

  1. Reduces costs. The main reason why we use SMT is to reduce costs. It is cheaper to produce, and the parts do not have to replace them often.
  2. Time-saving. Time-saving is also an essential factor that makes SMT such a popular process for mass production. This efficiency reduces the time needed to produce small electronic devices. It then brings these products to market faster than their competitors.
  3. Increased quality. After fixing the components in place, they become more reliable and less prone to early failure in their lifetime.
  4. Simplified assembly. After fixing the components on the board, the manufacturer makes them easier to assemble. It also means that there is less of a chance to assemble things incorrectly or accidentally.
  5. Less of an error rate: With everything in its proper position on the board, there is less chance for error during assembly. The manufacturer can spot problems sooner and fix them on the assembly line itself. This is before they cause any damage or defects to the finished product.

The main disadvantages of using SMT

There are also some disadvantages to using SMT, which include:

  1. High level of automation: Compared to other manufacturing processes, there is more need for automation with SMT. The process involves using robotics and automated machinery. It can be costly and sometimes disruptive, especially during peak times.
  2. Many parts: The complexity of the components makes this process more difficult than other techniques. Using the same adhesive would lead to persistent issues, significantly if misused or at too high a temperature.
  3. More parts to assemble: With SMT, there are generally more parts than other manufacturing processes. It isn’t easy to place all the components and secure them within their respective component packages before final assembly.
  4. High temperature. High temperatures can cause issues for SMT. It is because components generally need to place them in position before heating up and melting the adhesive onto the board’s surface. This temperature change can cause a component to shift or become stuck in place on the board.
  5. Different components. Depending on the components used, SMT can be a more complicated process than other manufacturing techniques.

SMT applications

SMT has many different applications, which include:

  • We use this type of application to create LCD screens for vehicle infotainment systems or central consoles. We can also use SMT for most vehicle systems, including the creation of GPS tracking units, navigation panels, radios, and even TV screens.
  • Consumer electronics. This is another area where we commonly use SMT to complete different tasks. It includes creating cellular phones or Bluetooth devices. In this instance, the processes used are similar to those of manufacturing printed circuit boards.
  • IT: The IT industry is one where SMT has been responsible for creating many electronic assemblies. These include creating newer devices such as computer processors, keyboards, mice, and even gaming consoles.
  • Medical: The medical industry has also found many uses for SMT in the creation of components. These include patient monitors, surgical instruments, and even motion sensors.
  • Military: The military sector uses SMT to create electronic assemblies for military use, such as communications equipment and radar systems.
  • Industrial: One area where we use SMT extensively by industrial users is assembling mechanical devices such as machine tools and laboratory equipment.
  • Aerospace: This sector uses SMT to create aircraft components such as surveillance systems and control panels.
  • Sport: One area of sport that is beginning to use SMT applications is golf equipment, such as putting mechanisms and golf cart motor controllers.

Future of SMT

As SMT in manufacturing is becoming more widely used, it has also started to face competition from other forms of manufacturing equipment. As a result, many companies are looking at ways to improve current systems or even develop new methods to maintain their competitive position in the market.

One area where SMT has developed is the creation of track systems, which are essential in placing different components during the assembly process. These systems are programmable and can guide the component through the entire placement process without human assistance or interference. In some cases, it may even be possible to place components at different points on a PCB at each stage of production. In this way, the company may find that it can use the PCB to its full potential and create a more cost-effective finished product by eliminating wasted time or effort.

Other prospective areas for SMT manufacturing include:

  • SMT offer: These offers are essential for the creation of electronic assemblies and components. They provide a more efficient way of creating finished products and increase the efficiency of the production process.
  • The SMT conversion: We use this conversion to convert existing component components into different types of products, although this often involves replacing existing parts with new ones that use SMT technology. For example, we may convert printers into copiers by replacing the existing inkjet heads with inkjet cartridges containing SMT technology for easier placement and removal.
  • SMT assembly: This is where one loads the components into their final position on a PCB. Such a process ensures that they are all in the correct location before sealing with solder.
  • SMT fixturing: You create a design and then place onto a carrier containing components. Next stage is soldering to the board using SMT technology and equipment.
  • The SMT testing: This occurs after placing all components onto a PCB at the end of production. We often carry out SMT testing using devices designed to pick up the components off the board and place them into small test boards or containers for further checking.
  • Magazinefed SMT line: We use this for highly automated production processes. The we place printed circuit boards in the magazine feeder, rotating them through a machine tool that holds each PCB during its process.
  • SMT equipment: This includes all of the tools and machinery used to manufacture SMT.
  • Robotic SMT placement: This is where we use robotic systems to place components onto a PCB without the help of humans. They may also move components around on the board during production, although these systems can be quite expensive to procure.


Many companies use SMT technology today. Whether they are manufacturers of equipment or actual contract manufacturers. It provides a highly automated process that is both viable for mass production and cost-effective. The ability to place components into position precisely means that there are no wasted resources or time mistakes made in the construction of the final product.

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