The maximum load that can be applied vertically to the stage and along the surface of the stage. This so-called 'side load' capacity is limited by the load capacity of the bearings.

 

Refers to the amount of force that is necessary to produce a given amount of deflection.

 

The lead screw corresponds to the principle of screw-nut combination. However the screw and the nut respectively are highly precise manufactured. In combination with particular thread pitch and corresponding choice of material static and sliding friction can be reduced to minimum. In spite of high quality of manufacture the lead screw shows some axial backlash . This can be eliminated with help of preload. A limited lifetime is due to friction of the sides of threaded nut and threaded screw. The lead screw is not suited for highly static and dynamic loads.

 

Balls roll on a ground or rolled shaft, having a helical groove. The balls support themselves in a helical groove with same pitch which is incorporated in the nut. Due to the revolving shaft the balls roll in the groove and move the nut (if not revolving) one screw pitch per rotation (further). The nut incorporates a recirculationsystem returning the balls that arrived at the end to the beginning of the nut. This model allows execution of linear motions by rotatory movements. This ball screw shows high efficiency. Stick-slip effect does not occur. Due to selected balls a thread-nut combination with zero backlash can be achieved.