Ball screws suit large powder presses

S-HTF series ball screws from NSK are for the first time enabling powder-press manufacturer Osterwalder AG to employ servo-electric drives on its larger machines, rather than conventional hydraulic drives.

As a result, new systems such as the Osterwalder OPP 2000 multi-level machine with 2000 kN press force, use around 80% less energy than hydraulic counterparts of equivalent power output. In addition, pressed parts are produced with significantly higher dimensional accuracy, which reduces the amount of reworking and substantially lowers process and material costs.
Lyss, Switzerland-based Osterwalder offers a wide range of machines, and with the CA-SP and CA-HM electric powder presses introduced around five years ago, brought to market a completely new type of drive technology. Direct Drive Technology (DDT), as it is known, comprises servo-electric motors and NSK ball screws, and thus replaced the hitherto dominant hydraulic drives in this field of application.
The DDT drive principle has proven itself over the past five years, initially for press forces up to 160 kN, and then up to 640 kN. As a result, it was only logical for Osterwalder to take the next step and equip its larger presses with this drive technology. However, the HTF series from NSK and comparable ball screws from other manufacturers reach their limits here with regard to nominal service life.
As part of its ongoing development programme, NSK had in the meantime developed its S-HTF ball screw series, which would prove extremely timely for Osterwalder. S-HTF ball screws offer a higher dynamic load capacity with the same dimensions, thus delivering a service life that is significantly extended.
Endurance tests performed in the NSK laboratory showed that the TF technology used in the ball screws of the S-HTF series results in triple the service life, as well as a 30% higher dynamic load capacity.
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