Servo actuators for a hoseless future

>Schmale Maschinenbau, based in Altena, Germany, about 25 miles south of Dortmund, says its latest processing machine, the X2000NC, constitutes a "minor revolution", being the first machine that's virtually oil-free. Rather than the more familiar hydraulic systems, this innovative wire, pipe and strip processing centre employs electronic motion control.

>Key to this control is TPM+ Power 050 servo geared actuators from Wittenstein. Schmale sales and service manager Andreas Goseberg comments: "The servo axes of the processing centre manage without any hydraulic assist. The decision to do away with all hydraulic hoses and units means the spectre of leaks in the hydraulic circuit is no longer hanging over users. What's more, the amount of maintenance work has been reduced because the hydraulic system no longer has to be filled, bled and cleaned - quite apart from the problem of disposing of the hydraulic oil."

>Highly compact, the TPM+ Power 050 provides a  motor output of 18.4kW, maximum acceleration torques of 750Nm at the output and an overall length of just 346mm including the brake and the encoder. This makes the TPM+ power 050 motor-gearhead units a viable alternative to hydraulic pressure systems when it comes to power and integration. Managing director Daniel Schmale enthuses: "In machines with several dozen auxiliary axes, these servo actuators can reduce the size of the footprint by as much as forty percent."

>There are big savings in energy consumption as well, as Wittenstein's Andrea Esser explains: "Sample calculations with different machine configurations, numbers of axes and cycle rates demonstrate the enormous potential for improving energy efficiency. Up to 70% of the total energy demand can be economised compared to traditional hydraulic manufacturing." The machine is far simpler to operate, too, thanks to the servo technology. The electronic control system merely needs to be told a few parameter values such as the stroke and the number of degrees, which can be entered on a touch screen. All mechanical cams have been eliminated from the forming processes, as has the time consuming task of retooling the machine. Servo control simultaneously makes the system extremely flexible.

>Daniel Schmale comments: "If the worst comes to the worst, it's much quicker to replace an actuator than to repair a hydraulic problem. So the TPM+ Power 050 also helps optimise machine uptime." These manifold advantages have also persuaded Schmale to use the servo actuators in other projects. "A project involving several servo actuators in the TPME 500 series is currently under way," reports Wittenstein product manager Siegfried Wallauer. This actuator series uses a water cooled motor with 107kW peak power and 63kW continuous power. "Owing to the innovative cooling technology, the continuous power has been doubled and there's been a significant improvement in productivity," comments Wallauer. "Yet in spite of this high power density the maximum surface temperature is no more than 50°C."

>Schmale forming technology and Wittenstein servo actuators have joined forces to bring the hydraulic era in this segment to a close and pave the way for a new age.