A Pick and Place machine places the components on the printed circuit board (previously silk- screened with tin paste and a reflow oven) and welds the electronic components.
With the SMD technology, high assembly speeds of up to 60,000 components per hour can be achieved.

THT assembly is an old technology, however not completely outdated, that consists in the manual assembly of the components by inserting the pins into the printed circuit. A wave welding creates the union of the pin with the printed circuit.

The two technologies are often used at the same time, but the future is the SMD as we can see in many markets like mobile phones.