METHOD FOR TEMPERATURE COMPENSATION IN A POSITIONING SYSTEM

摘要

A positioning system and a method of compensating for thermal expansion variations in a positioning system, as well as a component mounting machine, a jet dispensing machine, and a dispensing machine, including such a positioning system. The positioning system includes an elongated beam (104) extending along an axis (x), where the shape of the beam is subject to variations due to thermal expansion during operation of the positioning system. The system comprises a positioning unit (106) movably suspended on the beam, at least one motor for providing movement of the positioning unit along the axis, and at least one work head (112) mounted to or integrated with the positioning unit. A shape permanent, elongated reference element (110) is provided, which has a longitudinal extension along the axis, substantially in parallel to the beam. A reference distance is measured between the positioning unit and the reference element at a plurality of locations along the axis. The measured reference distances are used during positioning of the positioning unit for compensating for thermal expansion.