In machining centers employed on production lines, it is important to obtain maximum speed from the machine without sacrificing accuracy. One of the limiting components for both of these parameters is the spindle used for axis movement. Conventional machines employ a rotating threaded spindle to move the tool carriage back and forth as required. An alternative method, developed by Bosch Rexroth AG, uses a non-rotating spindle. A nut in the carriage, rotated by an alternating current servomotor, produces the relative tool carriage movement along the spindle.

Particularly attractive for applications where spindle lengths as long as 7.5m are involved, the MHS 40 direct-drive system offers several advantages:

Although the servomotor/nut configuration gives a faster drive, Bosch Rexroth has achieved this without sacrificing positioning accuracy. This is at least in part due to the direct drive which needs no couplings or drive belts. When the servomotor/nut is used in combination with a glass scale, or when it is used with a measurement system integrated into the guide rails, the system has a specified accuracy for linear positioning of more than one micrometer.