SMT assembly (Surface Mount Technology) is also known as SMD (Surface Mount Device). In this area of technology, electronic components are attached to the surface of a PCB. In the technology that preceded SMT, known as PTH (Pin Through Hole), the electronic components' pins or terminals are manually inserted and soldered through holes in the printed circuit board. In this type of technology (PTH) human means are used to perform the assembly. The soldering of the components is done with a reflow machine in which the liquid solder flows along the underside of the printed circuit.
In SMT technology, component inserting machines are usually used (pick and place, chip placer and large placer) during the entire production process, from the application of solder paste up to the assembly of components and the fusion of the solder paste due to the components' small sizes and sensitivity, which require a great deal of precision and demanding very strict control of the process' parameters.
