SMT – SMD and THT Assembly

PCB Assembly

Automatic assembly technologies at TI-Electronic:

  • THT – Through Hole Technology
  • SMT – Surface Mount Technology

THT Assembly:

At Through Hole Technology the outputs of the parts (which may be fix or flexible) are placed in holes on the side of the circuit unit to be printed and the outputs of the parts are soldered on the other side of the panel. The method of wave soldering is used for this process.

The main disadvantage of this technology is the fact, that both parts of the mounting panel have to be used by the parts.

SMT – SMD Assembly:

At the SMT – Surface Mount Technology The outputs of the parts are not placed in holes but fixed in the appropriate access points on the panels. This way the electronic outputs have a direct contact with the contact surfaces created on the panel, the so called pads.

Advantages of the SMT Assembly:

  • There is no need to create holes on the surface of the printed circuit unit
  • The costs of the production process can be decreased and the process can be automated
  • More practical as the parts need less space for storage

Variations of SMT Assembly:

  • Pure surface assembly – only SMD parts are used for assembly
    • One-side surface assembly (REFLOW)
    • Two-sides surface assembly (double REFLOW)
  • Mixed assembly – both SMD and traditional parts are used for assembly
    • Ono ne side SMD, on the other side RAD-CP parts
    • In case of mixed surface assembly (REFLOW-RAD-CP)