IPG IX-6168-PS, Hardware Reference Manual

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Beam Delivery System
8-4
Fluence and Optical Damage
It is important to avoid placing any component too close to a focal point of the laser
beam when working with beam delivery components. The beam’s concentrated
power (fluence) near a focal point is strong enough to quickly ruin an expensive optic
or other component.
As a rule, no optical component should be exposed to more than 300 mJ/cm
2
. To
calculate the beam’s fluence at any location, divide its total energy by its cross-
sectional area. For example, if the laser is operating at 150 mJ and the beam size at a
turning mirror is 5

10 mm, then the fluence on the mirror is 150 mJ/(0.5 cm

1.0 cm),
or 300 mJ/cm
2
.
Note: IPG Photonics does not warrant optics against damage caused by focusing a laser on the optic.
Pneumatic Beam Stop
The pneumatic beam stop, mounted after the laser output aperture, consists of an
aluminum plate attached to a pneumatic slide that moves into and out of the beam
path.
When pneumatic air pressure is applied, the beam stop moves out of the beam path,
allowing the laser beam to pass through. When air pressure is removed, the air
cylinder spring automatically moves the beam stop back into the beam, blocking the
laser beam from continuing through the BDS.
The beam stop is controlled using a software control or (in service mode only) using
the
Beam Stop
or
Shutter
switch mounted on the system. For more information about
the software I/O controls, refer to the IX Series “Setup and Operation: Chroma.Net”
software manual (IPG part number MAN-1) .
The beam stop has an integrated interlock switch that is part of the laser safety
interlock circuit. When the beam stop closes, the interlock is satisfied. The integrated
interlock switch is part of the laser safety interlock circuit for the entire system. For
more information about the interlocks, refer to “"Safety" Chapter 1.
Figure 75: Typical Pneumatic Beam Stop
Note
Some systems use a
manually operated beam
stop that has no automatic
or remote control.
Interlock and Data Connection
Pressure Sensor Switch
Pressure Sensor Switch
Air Cylinder
Heat Dump
Beam Shutter