3.1 Laser power
A high power laser is used to melt metal powder supplied coaxially to
the focus of the laser beam through a deposition head.The energy poured
into the melt pool gradually rises along with the laser beam’s
intensity. The laser power is the rate at which energy is emitted from
the laser beam. The laser is primarily used in the LENS process to
liquefy metallic powder to form a melt-pool, which solidifies upon
cooling to form the build voxel of a respective layer. Laser power is
possibly the most important process parameter in LENS, with variations
in this parameter having the greatest impact on the mechanical
properties of a part. When a dense structure is required, for example,
the laser power can be increased to avoid partial melting zones (porous
structures), but this can also result in undesirable microstructural
changes. In some cases, increasing laser power causes grain size to
increase, lowering hardness and potentially affecting other mechanical
properties.Not only does laser power affect mechanical properties;
according to Mahamood and Akinlabi analysis, surface roughness decreased
linearly with increasing laser power, improving surface finish.