positioners

A positioner is a device used to accurately position an object in space, often by providing controlled translation and/or rotation. Positioners are used where precise placement and orientation are required prior to processing, measurement, or operation.

Common classes include linear positioners (linear stages) that move objects along a straight axis; rotary positioners (rotary tables or goniometers) that rotate around a fixed axis; and multi-axis positioners that combine several axes to provide complex motion. Some devices provide tilt, tip, or spherical motion for three-dimensional orientation. Positioners can be manual, motorized, or servo-controlled.

Actuation is usually electric motors (stepper or brushless DC) with ball screws or leadscrews for linear displacement, or direct-drive torque motors for rapid motion. In some applications pneumatic or hydraulic actuators are used. Most modern positioners operate in closed loop with feedback from encoders or resolvers to achieve specified accuracy and repeatability; controls may be integrated in a controller or PLC.

Positioners find use in semiconductor lithography, micromachining, metrology and optical alignment, spectroscopy, microscopy sample handling, CNC and robotic workcells, welding and assembly, and packaging. In optics, positioners enable precise alignment of lenses, prisms, or telescopes; in semiconductor fabs they support wafer stages with nanometre-scale precision.

Key specifications include travel range, repeatability, resolution, load capacity, stiffness, backlash, thermal stability, and environmental suitability. Design considerations address rigidity, thermal drift, vibration, backlash compensation, and ease of integration with tooling. The term encompasses dedicated stages, goniometer assemblies, and precision rotary tables used to position workpieces or instruments.