Nano-positioning comes to large travel applications

Baldor has released a new type of X-Y positioning stage, which provides rapid sub-micron positioning over very large working areas.

Based on a combination of stepper and piezo-electric linear motors for coarse and fine positioning, the stage is available with travels of up to 3 x 1.5 m, for payloads of up to 1.8 kg.

These features provide scope for OEMs to improve productivity on a wide range of test, inspection and handling equipment involving ultra-fine positioning, such as wafer probing, fibre optic assembly, and biomedical sample manipulation.

Called NanoStepper, the stage provides two axes of movement implemented using the combination of linear stepper and linear piezo-electric friction motors. The linear stepper motor with its frictionless air bearing provides fast movement for coarse positioning of the payload, with a velocity of 1.5 metres/sec and acceleration of 19.6 metres/sec/sec. Mounted on this stepper motor is a piezo-electric friction motor which performs the subsequent fine positioning. This motor moves payloads at 100 mm/sec over a 10 x 10 mm area, and offers an optical encoder feedback resolution of 10 nm and a repeatable accuracy of <30 nm.

The NanoStepper stage provides its X-Y positioning capability within a small profile of just 31 mm. This is around half the height (or less) of a combination of a conventional air bearing stage and a piezo motor for example – a technology currently used by some OEMs producing ultra-fine positioning – and smaller still than any system based on rotary components such as belts or ballscrews and servo motors.

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