Selective Laser Sintering or Selective Laser Melting

       

SLS  is called Selective Laser Sintering. SLS
technology uses laser to irradiate the material powder and melt the special
added materials to achieve the function of binder, so as to combine the metal
powder to achieve metal printing.

SLM is called Selective Laser
Melting. SLM technology is the technology that the metal powder is directly
heated by the laser to melt completely in the cooling process.

The principle of these two technologies is
to use the thermal effect of the laser beam, but because SLS and SLM laser work
on different objects, they use different lasers. SLS technology is generally
used in long wavelength (9.2-10.8 μ m) CO2 laser. In order to melt metal
better, SLM technology needs to use laser beam with higher absorptivity of
metal, so it generally uses Nd YAG laser (1.064 μ m) and fiber laser (1.09 μ m)
with shorter wavelength.

From the material point of view, there is a
big difference between the two technologies. In addition to the main metal
powder, the materials used in SLS technology also need to add a certain
proportion of binder powder. The binder powder is usually metal powder with low
melting point or organic resin. SLM technology can make the material melt
completely, so it usually uses pure metal powder. Because the powder of SLS
technology is mixed powder, even if metal powder is used as binder, the
strength of metal materials with low melting point is generally lower, so the
strength of sintered parts of SLS technology is lower than that of parts with
single metal material. In addition, the mechanical properties and forming
accuracy of SLS sintered parts are worse than SLM due to the existence of
voids.