Soldering terminology

The long-wavelength end of the visible spectrum is about 0.76 to 0.8 µm. Beyond this range, we speak about far infrared radiation which corresponds to the rotation range of molecules while the spectrum of the molecular vibration falls within the range of near infrared. Radiation of this wavelength excites the molecules of a substance to thermal motion and increases its temperature. Using this method in the assembly of PCBs, individual spots can be warmed in a short time. Far infrared radiation is easy to use in reflow soldering ovens. IR generally stands for infrared.