Drive Systems
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Leadscrews
A drive system consisting of a screw and a nut coupled to the carrier. Leadscrews are self-locking but exhibit higher friction (motor output power, max. velocity) than recirculating ballscrews. M-125, and M-400 stages are equipped with leadscrews. Standard PI leadscrews have a pitch of 0.5 mm/revolution.Recirculating Ballscrews
Recirculating Ballscrew
Recirculating ballscrews reduce the sliding friction of leadscrews to rolling friction. They consist of a screw, a nut (ball housing) and a number of balls riding between the screw and the nut. When the screw rotates, the revolving balls transmit an axial movement to the housing attached to the carriage. Before the balls reach the end of the thread they recirculate to their original position through a channel in the housing. By selecting a certain ratio of ball diameter and thread diameter a backlash eliminating preload is generated.
Ballscrews show significantly reduced friction, wear and longer lifetime than leadscrews. They reach higher velocities than leadscrews with efficiencies up to 90 %. Ballscrews are not self-locking. M-500 stages are equipped with recirculating ball-screws. Standard PI ball-screws have pitches of 1 and 2 mm/revolution.
