What Is SMT Assembly?

Surface Mount Technology (SMT) involves the direct mounting of electrical components onto a PCB's surface. This intricate process commences with the application of solder paste through stenciling, followed by the precise placement of parts onto the board pick-and-place machines. Subsequently, the PCB assemblies undergo reflow soldering in an oven to fuse the solder. Throughout the SMT process, various inspection points are integrated to uphold the utmost quality standards at each manufacturing phase.

SMT Manufacturing Process

Solder Paste Printing
The printer employs a stencil and squeegee to apply solder paste at an angle between 45° to 60°. The flux acts as a temporary adhesive to secure surface mount components in position. Solder paste facilitates the connection between surface mount components (SMCs) and solder pads on the printed circuit board (PCB). Ensuring the accurate application of paste on each pad is crucial.
Components Placement
Pick-and-place machines are employed for mounting components onto the PCB. Components are extracted from their packaging using either a vacuum or a gripper nozzle, and then precisely positioned by the placement machine into their designated spots. The PCB advances along a conveyor belt as the swift and precise machines populate it with electronic components.
Reflow Soldering
Once the surface mount components (SMCs) are positioned, the PCB proceeds into the reflow soldering oven. Inside, it traverses through distinct zones including Preheat, Soak, Reflow, and Cooling, facilitating the soldering process. For double-sided printed circuit boards, these steps might be repeated, employing solder paste or adhesive to secure the SMCs in position as needed.

3 Common Methods of SMT Test



This inspection method relies solely on experience, demanding a relatively high level of expertise from technicians. Unlike other testing methods, it does not necessitate the development of a test program; instead, it relies on intuitive visual inspection of the targeted area.



AOI utilizes a cutting-edge vision system, innovative lighting techniques, high magnification, and intricate processing methods to achieve a high defect capture rate swiftly from the surface. Primarily employed on production lines, this testing method focuses on detecting various defects during the operational process.



X-ray technology relies on a transmitter within the machine to emit high-energy electrons, generating X-rays for imaging samples by penetrating them. As X-rays interact differently with objects of varying densities, they produce distinct images, which subsequently reveal the location and morphology of defects within the sample.

Adventages of SMT

Allow the use of smaller components.

Provide the maximum flexibility in constructing PCBs.

Reduce manual intervention in component placement.

Lower material costs.

Simplify the manufacturing process.

Smt Lines


FAQ: Your Guide to SMT.

Here are answers to some common questions and key considerations when choosing SMT.

what is surface mount technology?

what is surface mount technology?

Surface mount technology (SMT) stands as the primary method employed in electronic manufacturing for assembling printed circuit boards (PCBs).

What is SMT PCB?

What is SMT PCB?

SMT PCB assembly involves mounting electronic components directly onto the surface of printed circuit boards (PCBs), offering advantages like compact designs and improved performance.

How does SMT electronics assembly work?

How does SMT electronics assembly work?

Manufacturing electronics with surface-mount technology (SMT) entails the automated assembly of electronic components, where machines precisely place them onto the surface of a printed circuit board (PCB).

What is the SMT Manufacturing Process Step by Step?

What is the SMT Manufacturing Process Step by Step?

SMT manufacturing is a standardized procedure in electronics contract manufacturing, yet the intricacies within the process can significantly influence the success or failure of the project.

What is SMT Manufacturing?

What is SMT Manufacturing?

Surface Mount Technology (SMT) is a modern electronic assembly method where components are directly soldered onto a PCB's surface, eliminating the need for through-holes.

What is an SMT Line?

What is an SMT Line?

SMT production lines use advanced components for efficient assembly. High-speed machines and automated systems minimize errors and downtime, ensuring peak productivity. Continuous improvement keeps these lines adaptable to industry demands.

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