Ultra-Precision Linear Motor Stages

The XM is the ultimate solution for the most demanding manufacturing and test and measurement applications. It meets ultra-precision motion requirements with high dynamics and reliability for 24/7 production environments. Typical applications include semiconductor wafer inspection, sensor test and calibration, laser machining and ultra-precision assembly.
Unlike screw driven stages, the XM employs a center-driven, ironless linear motor as the driving element. Since the linear motor is a frictionless direct drive device, there is no backlash or hysteresis, wind-up or stiction limiting the motion performance. The linear motor drive also offers the advantage of higher speed, acceleration and system responsiveness with no wear to motor brushes or drive screws. The extra-large, ironless motor coil ensures zero cogging for ultra smooth velocity control and provides higher efficiency compared to alternative stage designs. This results in significantly less heat generation, which is generally the main limit for ultra-precision motion applications. To further improve thermal management and its effect on stage performance, the XM also has the benefit of a sophisticated length decoupling of the magnetic track from the stage carriage.
XM stages are machined from stress-relieved 7075 aluminum, ensuring long-term strength and stability. All critical stage surfaces undergo multiple machining processes and precision grinding under strict temperature and quality control to further improve overall performance and accuracy. The T-shaped carriage used on the XM provides the optimum solution for precision XY assemblies without impacting the stage preload. It also more robust and is more tolerant to non-ideal mounting conditions than stages with a C-shaped carriage design.
To ensure the most accurate trajectory control, XM stages feature best-in-class matched pairs of anti-creep crossed roller bearings. The absence of recirculating elements in the XM leads to outstanding ripple-free motion adequate for the most demanding scanning and inspection systems. Moreover, the geared retainers on these bearings prevent bearing cage migration, which can occur with other linear bearings.
Precision position feedback is supplied by a high accuracy LIF 481 Heidenhain Linear Scale. The precision alignment and mounting of this low thermal expansion scale in the center of the stage minimizes the impact of temperature changes on stage repeatability and accuracy. The encoder signals are interpolated by Newport’s XPS motion controller with sub-nm resolution and less than 10 nm noise for outstanding position sensitivity and stability. Absolute home position and limit signals are incorporated on the same scale without any further electronics or mechanics for improved reliability and accuracy. In general, all electronics are attached to the stationary base, so there are no moving cables inside the stage. This results in an extremely compact design with exceptional reliability and safety.