“All-In-One” USB micro-positioning stage provides sub-micrometer precision and nearly zero friction under all load conditions
New Scale Technologies, Inc. today announced it has added absolute encoding to its M3-LS Linear Smart Stage, a USB micro stage with fully-integrated drive electronics and the industry’s smallest all-in-one positioning stage. Absolute encoding eliminates the need to “home” the stage on power-up. It is a significant improvement over stepper motor driven stages, which must be homed to locate the zero reference position every time power is cycled, and during operation can lose count of steps moved.
The M3-LS Smart Stage is driven by a self-locking SQUIGGLE piezo motor and holds position when power is turned off. When restarted, its absolute encoding allows it to move directly and immediately to the commanded position with 0.5 µm resolution.
Absolute Encoding Eliminates Process Disruptions
“Absolute measurement of linear position is a big hit with our customers,” said New Scale’s chief technology officer David Henderson. “They can set a position, hold it with the power off, turn the power back on and resume their work -- without having to disrupt their experiment or process by moving the stage to a zero reference mark first. Absolute encoding simplifies integration, saves time, and avoids interference with sensitive processes.”
To achieve absolute encoding, New Scale integrated a low resolution optical encoder into the stage to complement the stage’s existing high resolution magnetic encoder. On power-up, the M3-LS automatically queries the optical encoder to determine absolute stage position within 0.5 mm. It combines that result with the higher-precision magnetic encoder reading to determine absolute position with 0.5 µm resolution.
Innovative Slide is Nearly Frictionless Under All Load Conditions
Henderson explained that customers have been equally enthusiastic about the M3-LS Smart Stage’s precise and very low-friction bearings.
“We created the M3-LS Smart Stage to solve the friction and clearance problems of commercial bearing guides and at the same time optimize the internal arrangement of the motor and position sensors,” he said. “We integrated the bearing guide so our customers don’t have to, and eliminated a major source of their design and integration headaches.”
For the M3-LS Linear Smart Stage, New Scale developed a novel slide with six radial ball bearings arranged in a kinematic “v” guide-way. The design has zero clearance, high stiffness and nearly zero friction. Significantly, the friction is uniform over the entire travel range, under high direct loads and side loads, and has low sensitivity to particles.
In contrast, many commercial micro stages employ ball or cross roller bearings in cages which can migrate off center, with “cage creep” causing friction to increase by more than an order of magnitude. Other commercial micro stages use recirculating balls that inevitably touch each other while moving along the recirculating path, causing intermittent high friction spikes. Both types of stages are sensitive to particle contamination and the preload needed to achieve zero clearance.
Specifications and Applications
The all-in-one M3-LS Smart Stage measures less than 29 x 20 x 10 mm and has 6 mm travel with less than 10 µm run-out. All electronics are completely integrated in the stage housing and accept simple high-level motion commands via USB, I2C or SPI standard serial interface.
The stage requires only 3.3 V DC input and can be powered by USB or standard batteries, making it ideal for motion in hand-held, mobile and portable instruments including miniature microscopes or spectroscopy systems. It can be used to miniaturize micro assembly and biomedical probing or sampling systems, UAV/UGV controls and optics, miniature camera systems and more.
M3-LS stages are easily assembled into two-axis and three-axis systems. Longer-travel versions are in development.
Find out more about New Scale Technologies' absolute encoding in tra-compact M3-LS Linear Smart stages.