Precision Gantry Systems

Ultra Precision Gantry

Magnetically preloaded XY air bearing gantry
Over one meter X and Y travel with submicron stability
Dual encoder Y-axis feedback for dynamic yaw control of crossbeam and active error correction
Zero cogging linear motors for ultra-smooth scanning motion
Optional Z-axis modules, vibration isolation and dual beam designs
Ideal for Flat Panel Display Processing

Anorad's Ultra Precision Gantry incorporates air bearing technology to permit virtually frictionless motion and dynamic performance well beyond the capabilities of conventional mechanical bearings. These large systems feature a massive granite base and rigid steel risers to create an extremely stable platform. A magnetically preloaded XY air bearing system - with well over 1 meter of travel in each axis - is affixed to this rigid structure and provides the high accuracy multi-axis motion. The lightweight moving X-axis crossbeam has dynamic yaw control through use of specially engineered supports. This enables the moving carriage to continuously maintain optimal alignment with a workpiece located on the system's large granite reference surface. Dynamic yaw control is achieved using dual linear encoder feedback on the Y-axis and sophisticated servo control algorithms that identify and compensate for minor workpiece misalignments. Even with travel that can exceed 1.5 meters, it can deliver micron-level repeatability and accuracy with submicron position stability over its full travel.

Air bearing technology virtually eliminates friction for ultra-precise motion control

The Ultra Precision Gantry uses Anorad's patented zero-cogging brushless linear servo motors driven by sinusoidally commutating servo amplifiers. Non-contact design elements assure cleanroom compatibility and include optical encoders, brushless linear motors and air bearing guides that minimize particle generation for extremely clean, low-maintenance operation. The result is an extremely robust and responsive system that provides rapid move and settle rates as well as extremely smooth constant velocity scans to set new performance benchmarks for large travel precision XY motion.

One potential use for the Anorad Ultra Precision Gantry is in flat panel display (FPD) applications. The systems are available in travels large enough for many common display sizes and Anorad can supply them with optional value-added equipment including vibration isolation systems, a variety of precision Z and Theta axes, welded steel support frames and complete servo drive and motion control packages.

Specifications

Parameters	Axis	Specification
Travel 1	X	1370 mm
	Y	1540 mm
	Z	78 mm
Straightness	X	± 5 µm
	Y	± 3 µm
	Z	± 2 µm
Flatness	X	± 6 µm
	Y	± 2 µm
	Z	± 2 µm
Orthogonality	X to Y	± 5 arc-sec
Orthogonality	Z to XY Plane	± 2.5 arc-sec
Pitch	X	± 7.5 arc-sec
Pitch	Y	± 1.0 arc-sec
Yaw	X	± 6.5 arc-sec
Yaw	Y	± 0.5 arc-sec
Resolution 2 (before controller 4x)	X,Y, and Z	± 0.05 µm
Repeatability (3 σ)	X	± 1.5 µm
	Y	± 1.5 µm
	Z	± 0.7 µm
Accuracy (3 σ)	X	± 3.0 µm
	Y	± 2.5 µm
	Z	± 0.8 µm
Position Stability 4	X and Y	± 0.2 µm
Position Stability 4	Z	± 0.1 µm
Velocity 3	X and Y	450 mm /sec
Velocity 3	Z	100 mm / sec
Acceleration 4	X and Y	3,000 mm / sec²
Acceleration 4	Z	2,000 mm / sec²
Typical Move Times 4	X, Y, and Z	See Performance Graphs

Notes: Specifications are stated per axis. Anorad offers custom, higher performance, and error mapped systems by request.

Includes overtravel before contacting resilient stops
Resolution available from 0.01 µm to 5 µm based on application requirements
Maximum velocity is dependent on encoder resolution and controller input frequency
Load on X-axis will affect overall system performance, contact Anorad application engineering for details

Performance Graphs

Move Times

All move times include 60 millisecond smoothing times
All move times include settling within ± 1.5 µm of target point

The plots above are that of a single machine under specific test parameters, depending on the application requirements, results may vary

Angular Error Plot

Dynamic yaw control keeps yaw error under 1 arc sec

Numerical Analysis: ISO (modified) 3.0 σ>
Accuracy (A):	0.75 as.
Accuracy (A):	0.56 as.
Accuracy (A):	0.71 as.
Repeat:	0.46 as.
Repeat:	0.00 as.
Repeat:	0.00 as.

The plots above are that of a single machine under specific test parameters, depending on the application requirements, results may vary

Linear Error Plot: X-axis

X-axis unmapped accuracy (3 σ) over full 1370 mm travel is better than ± 3 µm (6 µm) and repeatability is ± 1.5 µm (within 3 µm)

Numerical Analysis: ISO (modified) 3.0 σ Algebraic Sign Convention
Accuracy (A):	5.822 µm
Accuracy (A):	5.418 µm
Accuracy (A):	5.462 µm
Repeat:	2.125 µm
Repeat:	1.359 µm
Repeat:	1.940 µm

The plots above are that of a single machine under specific test parameters, depending on the application requirements, results may vary

Linear Error Plot: Y-axis

Y-axis unmapped accuracy (3 σ) over full 1540 mm travel is better than ± 1.5 µm (3 µm) and repeatability is ± 1 µm (within 2 µm)>

Numerical Analysis: ISO(modified) 3.0 σ Algebraic Sign Convention
Accuracy (A):	2.380 µm
Accuracy (A):	2.314 µm
Accuracy (A):	2.194 µm
Repeat:	1.181 µm
Repeat:	1.181 µm
Repeat:	.90019 µm

The plots above are that of a single machine under specific test parameters, depending on the application requirements, results may vary

Dimensions

Shown with optional Z-axis

The dimensions above represent Anorad's most common high-volume models, custom configurations available by request