The SMT PCB Assembly Process

The SMT technology was introduced for the automatic and rapid production of electronic devices. It has been constantly developed since the 1970s and is now an integral part of the electronics industry. Thanks to the appropriate equipment and technologically advanced production lines, SMT surface assembly can be fully automated, making the whole endeavor more profitable and efficient. What should you know about one of the most popular component assembly methods?

Currently, electronic components are mounted on a printed circuit board using SMT (Surface Mount Technology) or THT (Through-Hole Technology) systems. However, SMT allows for more densely packed elements on the boards and speeds up the entire assembly process. The trend towards miniaturization of devices and their components gradually causes SMT to replace THT. As a result, we can use tiny components to produce electronic devices without losing the quality of end products.

What are the characteristics of the SMT PCB Assembly Process?

Surface Mount Technology (SMT) is a method of placing electronic components (SMD) directly onto the surface of a printed circuit board (PCB). If required, CM can mount the details on both sides. SMT requires excellent precision when arranging electronic components on the pads. For this reason, the entire process is automatic and carried out on the appropriate production lines. Machines intended for SMT assembly are devices characterized by high precision and, above all, speed. That translates into greater possibilities in serial production needs and ensuring complete repeatability in the SMT surface mount production process.

The SMT PCB Assembly process – how does it work?

Most of the parts in SMT technology will be placed on the printed circuit board using a unique and fully automated pick-and-place machine, which puts the elements with great accuracy and at a speed of up to 40,000 pieces per hour. Before production begins, bare boards and components must be specially prepared. If the inspection team approves the details, CM can proceed with the assembly, which consists of four main stages:

  1. Applying solder paste (through a special template)
  2. Arranging elements collected from feeders on a PCB
  3. Multi-profile furnace brazing
  4. AOI quality control of assembly

Advantages of using SMT

SMT is by far the fastest and most convenient way to assemble PCBs. Process automation guarantees high precision and minimizes the risk of errors. Thanks to this, the manufacturer can count on reducing production costs. Proper quality control guarantees failure-free operation and functionality of the most complex systems, thus ensuring the manufacturer’s fine reputation. We can also indicate other advantages of the SMT PCB Assembly Process:

  • miniaturization of devices and high density of components arrangement,
  • the ability to arrange elements on both sides of the PCB,
  • the boards have better electrical properties, i.e., low connection impedance, which results in better properties at high frequencies,
  • less weight of elements results in better mechanical properties in the event of shocks or vibrations.

Surface SMT mounting-limitations

Elements mounted on a PCB with the help of SMT technology should have a flat surface so that a unique suction cup can pick them up and arrange them. However, CM can cover uneven elements with a special foil and avoid these difficulties. Besides, SMT has no other limitations. The SMT PCB Assembly Process has been developed for years, thanks to which it has reached a high level of advancement.

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