ALIO Industries stands out as a global leader in the provision of nanometer-level precise vacuum stages and robotic systems increasingly crucial across various industries such as fiber optics, biomedical engineering, micromachines, electronics, semiconductors, energy, optics, aerospace, and synchrotrons.
ALIO offers an extensive range of ultra-precise and repeatable motion control solutions, all of which, except their air bearing systems, are compatible with vacuum environments. These include linear, rotary, open center X-Y, hexapods, tripods, and goniometer stages. Available in high vacuum (HV, 10-7 TORR) or ultra-high vacuum (UHV, 10-10 TORR), these systems use materials and components specifically prepared and baked to ensure ultra-low outgassing.
Bill Hennessey, President of ALIO Industries says, “Nano-positioning applications are highly demanding, especially under vacuum conditions or when there is a need for extended travel, higher repeatability, speed, uptime, and lower costs. The design of drive mechanisms, bearings, feedback systems, motion controllers, and the overall kinematic structure is crucial for achieving nanometer precision in both atmospheric and vacuum environments.”
Typically, vacuum motion systems are made from bare 6061 aluminum or 300/400 series stainless steel. Since precision bearings in vacuum are usually made from 400 stainless steel, ALIO uses the same material for the motion system to ensure thermal variations do not affect performance, allowing the bearings to maintain preload. Suitable mechanical bearings for vacuum applications include recirculating ball rails, linear ball bearings, ceramic linear ball bearings, and crossed roller bearings. ALIO uses crossed roller bearings to achieve consistent nanometer-level precision. High-quality bearings, with rollers matched in size, ensure smoother motion, less friction, and minimal straightness deviation.
Hennessey continues, “Feedback systems in vacuum chambers need special designs to avoid outgassing. At ALIO we use optical encoders that read from a tape or glass scale, or directly from a stainless steel ring or a nickel-plated invar spar for higher precision. The invar scale, calibrated using an interferometer, offers near laser precision with excellent repeatability and accuracy, significantly reducing thermal effects. ALIO also employs piezoelectric-driven stages and ceramic linear and rotary servo motors for vacuum motion control. Ceramic servo motors are unique, offering unlimited travel without mechanical hysteresis and maintaining nanometer precision. These motors are robust, with high force and duty cycles, ideal for ultra-high vacuum environments due to minimal outgassing.”
The company uses a range of wet to dry vacuum-compatible lubricants, with Krytox being the most common. Krytox works well with mechanical bearings and screw systems but must be applied carefully to avoid causing the bearings to skid and stick. For ultra-high vacuum environments, dry lubricants like Molybdenum Disulfide and Tungsten Disulfide are preferred for their low friction and smooth motion.
For single to four-axis systems, serial kinematics are used but require precise design and machining to minimize errors. For extreme precision in five or more axes, parallel kinematic solutions are used, reducing error quotients and taking up less space. Hexapods with forward and inverse kinematics can enhance motion profiles by minimizing sub-micron errors.
Hennessey concludes, “Achieving nanometer precision in motion systems involves meticulously coordinating multiple critical components, especially within a UHV chamber where heat dissipation and outgassing are significant challenges. ALIO invites companies seeking nanometer-level motion control solutions for vacuum applications to collaborate and develop customized, cost-effective systems.”
For more information and expert consultation, contact ALIO Industries to explore the possibilities of advanced nano-precision systems.
