Controlling Laser Power; Control Signals - Novanta v40 User Manual

CONTROLLING LASER POWER

Small amounts of contaminants on the laser's output window (or on any optic in the beam path) can
absorb enough energy to damage the optic. Inspect all beam delivery optics periodically for signs of
contaminants and carefully clean as required. In dirty environments, purge laser optics using filtered
air or nitrogen to prevent vapor and debris from accumulating on optical surfaces.
Optics are fragile and must be handled carefully, preferably by the mounting ring only. Cleanliness is
another important issue affecting performance; a dirty or scratched lens will under perform and exhibit a
vastly shortened lifetime. When the application requires air (instead of nitrogen or argon) as an assist
gas, use only breathing quality air available in cylinders from a welding supply company. Compressed
shop air contains minute particles of oil and other contaminants that will damage optical surfaces. If
compressed shop air is the only choice available, it must be filtered and dried to the specifications shown
in Table 3-1.
Assist Gas
Air
Air
Nitrogen
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 v40 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 lasers. For more
information about the UC-2000, please consult the UC-2000 Laser Controller Operator's Manual.
Tickle pulse
V40 lasers incorporate a built-in tickle generator, freeing customers from the need to supply tickle
pulses between lasing commands. In cases where a 5 kHz, 1 μs tickle pulse is still sent to the laser via a
Caution: Possible Equipment Damage
Table 4-1 Assist gas purity specifications
Specification
Breathing Grade > 99.9996% purity or better
Compressed- 99.9950% purity or better, water-free; oil filtered to 5 mg/m3 or better; particulate
filtered to < 1.0 micron; dried to lower dew point below coolant temperature setpoint.
High Purity Grade > 99.9500% purity or better
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