GL4 Scanner Controller

November 28,2018

Related Glossary Terms

  • calibration

    calibration

    Checking measuring instruments and devices against a master set to ensure that, over time, they have remained dimensionally stable and nominally accurate.

  • interpolation

    interpolation

    Process of generating a sufficient number of positioning commands for the servomotors driving the machine tool so the path of the tool closely approximates the ideal path. See CNC, computer numerical control; NC, numerical control.

GL4 scanner controller

Aerotech’s GL4 scanner controller is optimized for Aerotech’s family of AGV scanners to provide industry leading settling times, long-term thermal stability and micron-level tracking accuracy due to advanced features such as full state feed-forward, 192 kHz servo rates and look-ahead-based velocity control. The GL4 uses advanced interpolation electronics to provide up to 26 bits of effective resolution while onboard real-time 2D calibration ensures accurate beam placement over the entire field of view.

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 GL4, this functionality is now available for scanner applications. 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.

Most competitive scanners have the power devices integrated directly into the head, along with the galvos and feedback devices. These power devices inject thermal energy into the scanner head causing drift in the feedback positions and changing offsets between the mirrors, which reduce marking accuracy. Some systems use PWM power stages to minimize heat input. However, this approach results in reduced tracking accuracy due to nonlinear effects 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.