Galvo and Controller Combination Offers Infinite Field of View and 24-Bit Resolution
Aerotech’s Nmark AGV-HP
August 22, 2012
• Wide range of apertures and focal lengths
• Many mirror surface treatments for a variety of laser wavelengths
• Nmark CLS controller has high-bandwidth linear power stage for quick settling
• Position Synchronized Output for consistent laser spot placement
Aerotech’s Nmark AGV-HP advanced galvanometers use innovative optical feedback technology to increase resolution to
greater than 24 bits. Both the standard AGV and higher performance AGV-HP series scanners may be directly driven by
Aerotech’s Nmark CLS galvo controller, which offers a full suite of advanced application tools that include Position
Synchronized Output (PSO) and Infinite Field of View (IFOV). The AGV is available with 10, 14, and 20 mm apertures with
standard F-Theta lens interfaces to provide maximum application flexibility. The AGV can be configured to accommodate
1064, 532, and 355 nm wavelengths, with other wavelengths available upon request. A variety of focal lengths are standard,
with correction files provided to remove lens distortion effects.
The ability to accurately place a laser spot as a function of X/Y axis position is a key feature of Aerotech’s linear
positioning tables for laser processing applications. With the release of the Nmark CLS, this functionality is now available
for scanner applications. The Nmark CLS offers Position Synchronized Output (PSO) that ties laser pulses directly to galvo position.
While other scanner controllers use time-based pulses to shutter laser light, the Nmark CLS PSO allows true position-based
triggering. The ability to accurately trigger the laser as a function of position removes the need to program mark, jump,
and polygon delays, resulting in reduced programming complexity. By using the Position Synchronized Output functionality,
scanner-based processes can now be programmed in the same fashion as traditional X/Y stage-based applications.
The Infinite Field of View feature seamlessly synchronizes servo and scanner motion under one controller environment
to allow fast scanner positioning over the entire servo travel, eliminating galvo field of view constraints.
The Nmark CLS has two high-power drive circuits, one for each axis in the scanner, that are optimized to get the peak
performance from the AGV product family.
Both the AGV and AGV-HP have thermally stable feedback transducers with virtually no gain or offset drift.
The Nmark CLS uses advanced interpolation electronics to provide greater than 24-bits of effective resolution.
Onboard real-time 2D calibration ensures accurate beam placement over the entire field of view.
Remote Power Devices
Most competitive scanners have the power devices integrated directly into the head, along with the galvos
and feedback devices. These power devices can inject considerable thermal energy into the scanner head
causing drift in the feedback positions and changing offsets between the mirrors, all of which detract
from marking accuracy. Some systems use PWM power stages to minimize heat input. However, this approach
results in reduced tracking accuracy due to nonlinear effects that are present when the galvo motors and
control currents reverse polarity. By moving the power stage out of the head, it is possible to use higher
performing transistors to drive the galvos and the heat source is effectively removed from the scanner resulting
in improved system accuracy.
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