CONTROLLING LASER POWER
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Table 4-1 Assist gas purity specifications
Assist Gas
Typical Purpose
Specification
Air
Cutting/ Drilling
Breathing Grade:
> 99.9996% purity; filtered to ISO Class 1
particulate level
Air
Cutting/Drilling
Compressed:
Instrument-grade air filtered and dried to ISO
8573-1:2010 Class 1, 2, 1 (< 10 1.0–
5.0 μm particles/m3; <
–40
°F (–40 °C) dew point; < 0.01 mg/m3 oil vapor)
Argon
Welding
High purity grade:
> 99.998% purity; filtered to ISO Class 1
particulate level
Helium
Welding
High purity grade:
> 99.997% purity; filtered to ISO Class 1
particulate level
Nitrogen
Cutting/Drilling
High purity grade:
> 99.9500% purity; filtered to ISO Class 1
particulate level
Oxygen
Cutting/Drilling
Ultra-Pure Grade:
> 99.9998% purity; filtered to ISO Class 1
particulate level
Controlling laser power
The Controlling laser power section includes subsections:
•
Control signals
•
Operating modes
Control signals
Much of the information provided in this section describes the use of a Novanta UC-2000 Universal
Laser Controller to provide PWM Command signals to the i401 laser. If using an alternate method of laser
control, thoroughly review this section, controlling laser power, as well as the following section, User I/O
connections, for an understanding of the signal requirements necessary to control I401 lasers. For more
information about the UC-2000, please consult the UC-2000 Laser Controller Operator’s Manual.
Tickle pulse
Tickle pulses pre-ionize the laser gas to just below the lasing threshold so that a further increase in pulse
width adds enough energy to the plasma to cause laser emission. Tickle pulses cause the laser to
respond predictably and almost instantaneously to PWM Command signals, even when there is
considerable delay (laser off time) between applied Command signals. All I401 lasers incorporate a built-
in tickle generator, freeing customers from the need to supply external tickle pulses between lasing
commands. Internal circuitry monitors the incoming PWM signal and determines the amount of time the
Danger: Serious Personal Injury
Because of phase differences, external tickle pulses may combine with the internally generated tickle
signal causing the LASE LED to flicker during the transition from tickle to lasing. Laser output may
occur if the LASE LED flickers.
