The beam emitted by any Class II, IIIA, IIIB and IV laser product should end its effective path in a
diffused reflection material with suitable reflectivity and thermal properties, or an absorbent material.
Whenever possible, the laser beam open patch must be located either above or below eye level.
Mirrors, lenses and beam splitters should be tightly mounted and subject to controlled movements during
laser emission to prevent accidental spectral reflection of the emission coming from Class IIIB or IV laser
product.
There are risk control procedures for each class of laser:
•
Classes II and IIIA
. They only require precautions to prevent direct, continuous view of the beam.
Momentary exposure due to accidental viewing is not considered dangerous.
•
Class IIIB
. These are considered hazardous when the naked eye is exposed to the direct beam or
spectral reflection. In order to prevent these situations, the following precautions must be taken:
(1) The beam must be used in a controlled area.
(2) The beam must end its useful path at a diffused material with a suitable colour and reflectivity
that allows the beam to be positioned while minimizing the risk of reflection.
(3) In the absence of the conditions specified in point 2, eye protection must be worn.
•
Class IV
. These may produce injuries caused by the direct beam or its specular and diffused
reflections. They also involve fire risk. In addition to the precautions mentioned in the previous
section, the following should also be used:
(1) The laser system must be installed, adjusted and operated only by qualified, trained and
authorized personnel.
(2) The area where the laser marking system will be operating must be identified with a suitable
warning sign (supplied by HITACHI)
(3) The beam and incidence area must be surrounded by the material resistant to the wavelength
emitted by the laser in order to avoid specular reflection in the invisible spectrum due to the far
infrared laser emission.
(4) The presence of people in the beam path must be avoided in order to prevent exposure to
emission or specular reflections.
(5) Carbon plates or other sufficiently thick refractory materials must be installed at the end of the
beam path. Nevertheless some precautions must be taken, as the surface of these materials
can vitrify after lengthy exposure, causing specular reflection.
(6) Whenever possible, the beam path must be located either above or below eye level.
In spite of all safety elements included in the laser marking system end user should wear safety goggles
that completely cover the eyes when operating the system, in order to avoid any injury caused by
specular emission- it is also advisable to wear cotton clothing, which is much more resistant to this kind
of emission.
Each country establishes its own safety standards concerning the sales and distribution of laser
products.
All of them are quite similar.
NOTE
The final path of the laser beam should end at some diffused reflectivity element
•LASER SAFETY STANDARDS 1-2
