Renishaw InfiniAM Spectral, User Manual

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InfiniAM Spectral
20
Description
7 .1 .3 Operating principle
Figure 4 shows the Renishaw optical module (20), the LaserVIEW hardware module (10) and the
MeltVIEW hardware module (2).
A fibre laser (1) emits intense laser light which reflects from a fixed mirror (11) and passes through
a dynamic focussing system (12). A small percentage of the laser light leaks through the first turning
mirror and impinges on a photodiode (10). The beam is reflected from a two-axis galvanometer mirror
system (19), passes through an optical window (16) and comes to a focus on the powder bed (14) of
the Renishaw AM system.
The interaction of the intense laser beam with metal powder results in a melt-pool (18) and
plasma (17). Plasma and melt-pool both emit in the near-infrared spectrum (700 nm to 1700 nm).
Radiation is emitted in all directions, with a small proportion propagating back up the beam line of the
Renishaw optical module. The coating on the first turning mirror has been tailored to reflect visible and
infrared wavelengths outside the primary laser wavelength. Therefore plasma and melt-pool emissions
pass through the mirror and into the MeltVIEW module.
Near-infrared emissions from plasma are separated from the near-infrared emissions from the melt-
pool using mirrors (8 and 7). Plasma emissions (700 nm to 1040 nm) are focused onto the surface of
an infrared sensitive photodiode (4), whilst melt-pool emissions (1090 nm to 1700 nm) are focused
onto the surface of a infrared sensitive photodiode (5).