Z-Lift Vertical Motion Systems to Address the Limitations of Traditional Z-Wedge Vertical Stages

ALIO Industries has developed its Z-Lift Vertical Motion Systems to address the limitations of traditional Z-wedge vertical stages. The design goals were to enhance the performance of linear stages when oriented vertically and to minimize their physical footprint. Inherent in the design of Z-wedge stages are multiple complexities: they consist of three machined components with intricate angles, three sets of bearings, a motor linked via a coupling, and an encoder, all of which contribute to considerable inaccuracies. Conversely, ALIO’s Z-Lift stages are engineered to deliver superior accuracy and repeatability.

The patented NANO Z® air bearing stages from ALIO are a breakthrough with their use of air-bearings combined with two voice coil motors within a compact design, allowing up to 50mm of travel. The utilization of air bearings reduces friction to almost nothing, which in turn provides unmatched accuracy and repeatability, reaching precisions in the low double-digit nanometers. This design incorporates variable counterbalancing to manage heavy loads such as wafer chucks while maintaining nano-level precision throughout the entire travel range. The strategic placement of the vertical force in alignment with the payload allows the stage to be positioned directly beneath the payload rather than adjacent to it, significantly reducing cantilever errors and virtually eliminating issues with pitch, yaw, and roll.

ALIO’s GeoSymmetric™ Vertical Positioning Stages represent another innovative approach, employing either voice coil or linear direct drives along with high precision crossed roller bearings. These stages feature various counterbalance options within a unique design that allows for flexible installation, thanks to the unique geometric shapes of the stages that provide mounting surfaces on multiple sides. Direct mounting of payloads to the stage enhances stability and reduces resonance problems. The symmetry in the component arrangement within these stages — where the counterbalance, motor, bearings, and encoder are centrally aligned — distributes mass evenly, leading to enhanced performance with bi-directional repeatability as fine as +/-45nm and travel ranging from 6mm to 70mm, supporting loads up to 30kg.

For applications requiring extended travel without sacrificing precision, ALIO offers linear motor-driven, low-profile Z-lift stages. These stages utilize similar design principles as the GeoSymmetric series, with central alignment of core components like the counterbalance and motor. These stages are ideal for applications where payloads need to be mounted directly onto the stage face and are available in configurations that allow for travel between 25mm and 170mm, and in the case of the Z-ABCB version, up to 200mm or more with a payload capacity of up to 25kg.

For industrial automation, large-scale metrology tools, or any application demanding significant lift capabilities with nanometer precision, ALIO’s vertical Z stages with precision ball screws are the optimal choice. These stages are powered by a frameless torque motor and feature pneumatic release spring engage brakes to handle up to 20kg without additional counterbalancing. For heavier loads, a “pneumatic boost” option is available, further enhancing the payload capacity to 50kg. Moreover, these stages boast +/- 100 nm bi-directional repeatability over travels up to 50mm, making them highly suitable for applications that demand high loads and extended travel ranges without compromising precision.

In imaging applications, achieving the perfect focus is crucial and often depends on the ability to adjust the distance between the sample and the optics. This is typically managed with a Z-axis focusing stage which may need to accommodate varying sample thicknesses, different objective focus requirements, or the need to handle different sample types. Additionally, some advanced microscopy techniques require precise focus adjustments to generate 3D images of samples, an area where ALIO’s direct drive focus stage technology excels, providing the required precision and flexibility for these demanding applications.

See our stages in action here – https://alioindustries.com/video/z-lift-vertical-motion-stages/

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