n MACHINE BUILDING n The drilling spindle needed the smallest, lightest motor possible. “This allows us to keep the mass to be moved for the five axes low, and thus achieve rapid positioning,” explains Guido Wittenauer, Stober’s representative handling the Soga account. In addition to drilling, the machine also had to perform countersinking operations. This requires highly dynamic motor controls. Stober supplied its encoderless Lean motor, which allows speed and torque to be set to any point, from a standstill to maximum speed, while providing full torque control. The motor is much lighter and smaller than an asynchronous drive with a similar output would be, and is said to be more costeffective and rugged than a servodrive. In addition, the motors have efficiencies of up to 96%, cutting Roma’s energy use. Each head has three motors placed as close together as possible. “Since our Leanmotor functions without an encoder, only one standard power cable is necessary, without any additional cores or shielding,” Wittenauer explains. The motors are paired with Stober’s 45mm-wide S16 double-axis controllers, which allow challenging movements. STO and SS1 safety functions are built in and certified in accordance with EN 13849-1 (Pl e, Cat 4). “Thanks to the serial connection of multiple controllers, the number of axes to be controlled can be scaled without limit,” Wittenauer points out. For power distribution, Stober’s patented Quick DC-Link modules click onto standard copper rails. They simplify the installation of the drive controllers. Stober not only supplied the machine’s components. It also took care of mechanical design and dimensioning. “We developed the idea that the motor would form one unit for the X-axis with the gearbox and helical gear together in project conversations,” says Soba’s MD, Fabian Gallenbach. The axes could be parameterised easily on site. Roma reports that the new machine is operating more reliably than its predecessor, and that reworking is no longer needed. n The five mounting heads move independently of each other on a gear rack.
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