High-precision and extremely gentle
Eisenmann uses a complete system comprising a synchronous servo geared motor, cable and matching drive controller from STOBER:
An industrial robot with a gripper handles rims of different sizes and weights in a paint line. Eisenmann had previously relied on pneumatic drive technology. However, it proved uneconomical and only allowed limited control. This is why this mechanical engineering company trusts technology from drive specialist STOBER, which supplied a system consisting of synchronous servo geared motors, cables and suitable drive controllers optimally tailored to the requirements.
“Our robot system can pick up a raw egg so carefully that it is not even damaged,” says Peter Butz, Product Developer at Eisenmann GmbH in Böblingen. This underscores the sensitivity with which the system can be controlled. Instead of handling eggs, the robot actually grips rims of different sizes and weights and supplies them to a paint line. In addition to industrial painting and handling systems, this mechanical engineering company also develops driverless transport systems and technologies for pre-treatment and filtration. “All our solutions are unique, because we tailor them to our customers’ specific requirements,” says Butz. “They vary in the complex interplay of process steps and the corresponding conveyor systems.” In its development work, the company focuses on solutions that are cost-efficient and save resources – always with the aim of creating clear, comprehensible added value for its customers.
From pneumatics to electronics
With this goal in mind, Eisenmann has also optimized the handling system. “It consists of industrial robots with one or more grippers. We had previously installed pneumatic drives,” explains Peter Butz. Initially, there was a lot to be said for them: They are simple, dynamic and comparatively inexpensive to buy. Yet they are considered inefficient and only allow limited control. In addition, compressed air generation is energy-intensive, and leaks cause additional losses and costs. For this reason, Eisenmann opted for electric drives. These are significantly more energy-efficient and economical to operate and allow direct integration of sensors.
After deciding on a servo-electric drive solution, the aim was to integrate this technology into the existing gripper concept in a practical way. As they examined the new project requirements, the Eisenmann developers began to focus on drive solutions from STOBER.
With Klaus Buschko as their contact person in Sales and Robert Boger in Application Development, STOBER worked with Eisenmann to develop a suitable solution. The starting point was a pilot system that showed that the competitor’s drive technology, initially used as a prototype, did not fully meet the requirements for controllability. In particular, the two-cable solution originally planned proved to be a disadvantage when during gripper movement.
High-precision drive technology
With the STOBER solution, the gripper attached to the robot first moves towards the component at high speed, then stops a millimeter before touching it and approaches the rim at creep speed in a controlled manner to pick it up. This allows a sensitive approach – even a raw egg can be safely gripped without damaging it. “A high holding torque is particularly important to us,” explains product developer Peter Butz. This is because the robot arm can stop moving abruptly and start up again quickly, while the rim must be held securely at all times. Therefore, the drive solution had to be lightweight and compact, since it is installed directly in the gripper.
STOBER supplied KL series helical bevel gearboxes with a directly mounted EZ synchronous servo motor. This compact unit offers good installation dimensions and high power density. “Thanks to their robust bearings and high-quality gearing, STOBER helical bevel gearboxes are extremely resilient and tilt-resistant,” explains Buschko. Another important feature of this series is its very smooth operation. Since the gripper moves along two axes, the compact SC6 stand-alone drive controller is used for control. If additional grippers need to be added, the SC6 can be combined with the SI6 drive controller, which is designed for multi-axis drive systems. This enables solutions with two to five grippers, allowing Eisenmann to respond to a wide range of customer requirements.
The geared motors and drive controllers are connected via STOBER’s One Cable Solution (OCS). The hybrid cable with the future-proof EnDat 3 protocol transmits both encoder data and power data via a single cable. The result is an integrated system consisting of a synchronous servo geared motor, cable and drive controller. This avoids the problem that would arise with the planned two-cable solution and significantly reduces the installation effort.
Independent of the robot type
STOBER has added additional PROFINET functions to the SC6 and SI6 drive controllers. In conjunction with the SU6 safety module, they support safety functions such as STO (Safe Torque Off) and SS1 (Safe Stop 1) via PROFIsafe. “The possibility of free programming allows Eisenmann’s developers to contribute their own know-how at specific points.” The result is a flexible, multifunctional system that can be integrated into different types of robots, regardless of the manufacturer.
During the project, potential for optimizing operation was also uncovered. During longer downtimes, the motors remain energized and thus generate heat. To avoid this thermal load, the drives were retrofitted with a brake.
STOBER also fitted torque arm brackets to the gearboxes. These absorb reaction torques or differential torques and transfer them to the surrounding support structure. This prevents the motor or housing from twisting. To achieve an even more compact design, the geometry of the supports was adapted accordingly.
Eisenmann now benefits from a drive system that is specially tailored to its requirements, as well as from responsive technical support. “With STOBER, we have chosen a future-proof, energy-efficient drive solution – one that is sensitive down to the last detail,” says Butz with satisfaction.
Image 1: Strong rim handling performance: Eisenmann’s industrial robot with gripper performs packaging operations safely, precisely and with process stability.
Image 2: Maximum sensitivity: The Eisenmann gripper can even grip a raw egg without damaging it.
Image 3: KL series helical bevel gearbox (right) with directly mounted EZ synchronous servo motor featuring the One Cable Solution (OCS).
Image 4: The STOBER portfolio includes drive controllers, geared motors and cables – so users can get all their drive components from a single source.
Photo credits: STÖBER Antriebstechnik GmbH + Co. KG
You can find high-resolution image material for downloading here.
STOBER develops and produces precise, highly efficient drive components and systems, including gearboxes, motors, gear racks and drive controllers for custom solutions. They are used in various industries, including automation and robotics, as well as the plastics, packaging and machine tool industries. STOBER has 14 locations and 80 service partners in over 40 countries. In addition to its headquarters in Pforzheim, Germany, there are also production facilities in Hungary and the US. The family-owned company currently employs around 1,000 people worldwide.
Contact data for country-specific publication:
| Germany: | Austria: |
| STÖBER Antriebstechnik GmbH + Co. KG Kieselbronner Str. 12 75177 Pforzheim Phone: +49 7231 582-0 sales@stoeber.de www.stober.com | STÖBER Antriebstechnik GmbH Hauptstraße 41a 4663 Laakirchen Phone: +43 7613 7600-0 sales@stoeber.at www.stober.at |
| Switzerland: | |
| STOBER Switzerland AG Rugghölzli 2 5453 Remetschwil Phone: +41 56 496 9650 sales@stoeber.ch www.stober.ch |
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