Laser source[edit]

As with selective laser melting, the laser power does not have to be especially high as long as the laser energy is sufficiently concentrated. The achievable rate of material addition depends on both the amount of laser power applied, and the heat of fusion of the feedstock and substrate materials. As different materials absorb different wavelengths of light, it is important that the wavelength of the laser source is appropriately matched to the material's absorption spectrum, to ensure that the amount of energy absorbed by the material is maximised. For example, using LMD to deposit steel is efficiently performed using IR laser sources, while for copper-based alloys green lasers have better absorption.^[5]