For a specific point of interest in three-dimensional space, accuracy is the difference between the actual position in space and the position as
measured by a measurement device. Stage accuracy is influenced by the feedback mechanism (linear encoder, rotary encoder, laser interferometer),
drive mechanism (ball screw, lead screw, linear motor), and trueness of bearing ways. The measurement reference for Aerotech linear products is a laser interferometer.
Straightness is a deviation from the true line of travel perpendicular to the direction of travel in the horizontal plane. For the stage assembly listed
above, a straightness deviation in the travel of the X-axis stage will cause a positioning error in the Y direction. A straightness deviation in the
travel of the Y-axis stage will cause a positioning error in the X direction.
Flatness is a deviation from the true line of travel perpendicular to the direction of travel in the vertical plane. For the stage assembly shown, a flatness
deviation in the travel of the X-axis or Y-axis stage will cause a positioning error in the Z direction.
Roll is a rotation around an axis in the horizontal plane parallel to the direction of travel. If the position of interest being measured is not located at the center
of rotation, then the roll rotation will cause an Abbe error in two dimensions. For the X-axis, a roll rotation will cause an Abbe error in both the Y and Z direction.
Pitch is a rotation around an axis in the horizontal plane perpendicular to the direction of travel. If the position of interest being measured is not located at the
center of rotation, then the pitch rotation will cause an Abbe error in two dimensions.
Yaw is a rotation around an axis in the vertical plane perpendicular to the direction of travel. If the position of interest being measured is not located at the center of
rotation, then the yaw rotation will cause an Abbe error in two dimensions.
Repeatability is defined as the range of positions attained when the system is repeatedly commanded to one location under identical conditions. Uni-directional
repeatability is measured by approaching the point from one direction, and ignores the effects of backlash or hysteresis within the system. Bi-directional
repeatability measures the ability to return to the point from both directions. Many vendors specify repeatability as ± (resolution). This is the repeatability
of any digital servo system as measured at the encoder. All of Aerotech's specifications, which include the effects of Abbe error, friction, etc. are based on
actual operating conditions and usage - not on theoretical, unachievable values.
The smallest possible movement of a system. Also known as step size, resolution is determined by the feedback device and capabilities of the motion system.
Theoretical resolution may exceed practical resolution.
Component of total error motion that occurs at integer multiples of rotation frequency perpendicular to the stage axis of rotation at a given axial location.
Component of total error motion that occurs at integer multiples of rotation frequency in an angular direction relative to the stage axis rotation. In previous
specification tables published by Aerotech, the term wobble was used and is synonymous; however, wobble is no longer preferred.
Component of total error motion that occurs at noninteger multiples of rotation frequency perpendicular to the stage axis of rotation at a given axial location.
Aerotech’s vast application experience, unmatched product scope, and extensive engineering capabilities make us the partner of choice for vacuum-compatible motion systems.
Since its inception, Aerotech has designed and manufactured the highest-performance motion control and positioning systems available, and our vacuum-compatible platforms
are no exception.
Aerotech has a long history of providing components and systems to the semiconductor and medical device manufacturing industries. This experience has provided extensive
knowledge of how to prepare stages for cleanroom use.
All maximum load values in the stage specification tables are based on the stage operating in a Normal Loading Condition. A Normal Loading condition results when the
load is attached to the stage with the center of gravity positioned directly above the bearings.
The condition of a surface or axis which is perpendicular (offset 90 degrees) to a second surface or axis. Orthogonality specification refers to the error from 90 degrees
from which two surfaces of axes are aligned.
Accuracy is defined as the difference between the commanded position and the actual position of a rotary stage. The accuracy can be influenced by the feedback device,
drive mechanism (motor type), axis of rotation error motions, thermal effects (such as environmental changes), and the accuracy of mounting surfaces. Aerotech measures
the accuracy of rotary tables using laser measurement techniques with ultra-precise index tables as the measurement reference. Unless specifically noted, Aerotech
specifies accuracy as a peak-to-valley deviation from the nominal position.
For a specific point of interest in three-dimensional space, accuracy is the difference between the actual position in space and the position as
measured by a measurement device. Stage accuracy is influenced by the feedback mechanism (linear encoder, rotary encoder, laser interferometer),
drive mechanism (ball screw, lead screw, linear motor), and trueness of bearing ways. The measurement reference for Aerotech linear products is a laser interferometer.
Straightness is a deviation from the true line of travel perpendicular to the direction of travel in the horizontal plane. For the stage assembly listed
above, a straightness deviation in the travel of the X-axis stage will cause a positioning error in the Y direction. A straightness deviation in the
travel of the Y-axis stage will cause a positioning error in the X direction.
Flatness is a deviation from the true line of travel perpendicular to the direction of travel in the vertical plane. For the stage assembly shown, a flatness
deviation in the travel of the X-axis or Y-axis stage will cause a positioning error in the Z direction.
Roll is a rotation around an axis in the horizontal plane parallel to the direction of travel. If the position of interest being measured is not located at the center
of rotation, then the roll rotation will cause an Abbe error in two dimensions. For the X-axis, a roll rotation will cause an Abbe error in both the Y and Z direction.
Pitch is a rotation around an axis in the horizontal plane perpendicular to the direction of travel. If the position of interest being measured is not located at the
center of rotation, then the pitch rotation will cause an Abbe error in two dimensions.
Yaw is a rotation around an axis in the vertical plane perpendicular to the direction of travel. If the position of interest being measured is not located at the center of
rotation, then the yaw rotation will cause an Abbe error in two dimensions.
Repeatability is defined as the range of positions attained when the system is repeatedly commanded to one location under identical conditions. Uni-directional
repeatability is measured by approaching the point from one direction, and ignores the effects of backlash or hysteresis within the system. Bi-directional
repeatability measures the ability to return to the point from both directions. Many vendors specify repeatability as ± (resolution). This is the repeatability
of any digital servo system as measured at the encoder. All of Aerotech's specifications, which include the effects of Abbe error, friction, etc. are based on
actual operating conditions and usage - not on theoretical, unachievable values.
The smallest possible movement of a system. Also known as step size, resolution is determined by the feedback device and capabilities of the motion system.
Theoretical resolution may exceed practical resolution.
Component of total error motion that occurs at integer multiples of rotation frequency perpendicular to the stage axis of rotation at a given axial location.
Component of total error motion that occurs at integer multiples of rotation frequency in an angular direction relative to the stage axis rotation. In previous
specification tables published by Aerotech, the term wobble was used and is synonymous; however, wobble is no longer preferred.
Component of total error motion that occurs at noninteger multiples of rotation frequency perpendicular to the stage axis of rotation at a given axial location.
Aerotech’s vast application experience, unmatched product scope, and extensive engineering capabilities make us the partner of choice for vacuum-compatible motion systems.
Since its inception, Aerotech has designed and manufactured the highest-performance motion control and positioning systems available, and our vacuum-compatible platforms
are no exception.
Aerotech has a long history of providing components and systems to the semiconductor and medical device manufacturing industries. This experience has provided extensive
knowledge of how to prepare stages for cleanroom use.
All maximum load values in the stage specification tables are based on the stage operating in a Normal Loading Condition. A Normal Loading condition results when the
load is attached to the stage with the center of gravity positioned directly above the bearings.
The condition of a surface or axis which is perpendicular (offset 90 degrees) to a second surface or axis. Orthogonality specification refers to the error from 90 degrees
from which two surfaces of axes are aligned.
Accuracy is defined as the difference between the commanded position and the actual position of a rotary stage. The accuracy can be influenced by the feedback device,
drive mechanism (motor type), axis of rotation error motions, thermal effects (such as environmental changes), and the accuracy of mounting surfaces. Aerotech measures
the accuracy of rotary tables using laser measurement techniques with ultra-precise index tables as the measurement reference. Unless specifically noted, Aerotech
specifies accuracy as a peak-to-valley deviation from the nominal position.
