What is the difference between SMT and THT?

The printed circuit board serves as the foundation of electronic devices, comprising various components that collectively form functional execution units. It provides essential electrical pathways for seamless operation. Constructing a complete PCBA board involves intricate processes, employing distinct assembly techniques such as SMT and THT.

Lets see the difference between SMT and THT below:

Conceptual Differences


SMT, or Surface Mount Technology, is an advanced assembly technique that involves mounting components directly onto the surface of a printed circuit board using adhesive or solder. This method allows for compact and efficient designs, enabling the creation of smaller and more intricate electronic devices. Further Reading: “What does SMT stand for in electronics?


On the other hand, THT, or Through-Hole Technology, is a traditional PCB assembly method where component pins are inserted into pre-drilled holes on the PCB. These pins are then soldered to create a secure and reliable connection. Further Reading: “What does THT stand for in electronics?”


Process Differences

SMT processIncoming Material Inspection → PCB Stencil → Solder Paste Printing → Component Placement → SPI Inspection → Reflow Soldering → Cleaning → PCBA Inspection.


THT process: Incoming Material Inspection→Manual/Automatic Plug-in→Manual/Wave Soldering→Cleaning →PCBA Inspection.


While both SMT and THT processes can incorporate automation, SMT offers greater compatibility with automated production due to its surface-mounted nature. However, for larger DIP components, manual insertion may still be required even in an automated Through hole PCB assembly. The primary distinction between the two processes lies in the component installation method and the final soldering process


SMT and THT: Technology Intersection


While SMT and THT differ in concept, their fundamental purpose remains the same—to accurately and reliably mount components onto circuit boards. As electronic technology becomes increasingly complex, a single assembly mode is often insufficient to meet all electronic application requirements. Therefore, these two technologies are often used together in PCBA, such as mobile phone motherboards and car controllers. These two technologies complement each other’s strengths, with SMT being suitable for small and highly integrated circuit boards, and THT being preferred for applications requiring mechanical strength or high-power components.


As the PCBA industry continues to evolve, the trend towards miniaturization, high performance, and high reliability in the electronics industry will persist. This means that electronics manufacturers must possess expertise in both SMT and THT to meet the demands of mixed PCB assembly.


However, not all PCBA companies possess strong Assembly capabilities, and there can be variations in PCB soldering quality among different companies. When seeking a PCBA partner for a new project, it is advisable to proactively assess their capabilities and service offerings, including equipment inspection and other relevant factors.


We Fubon Precision, a leading PCB manufacturer in China, has been engaged in PCB design for nearly 13 years. We own all expertise and tools required to complete powerful HDI PCB design, our team of experts has served customers from various industries ranging from medical, and consumer electronics, to automotive, and IoT. Contact us to get reliable PCB design services.