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Handling of grog tubes

Starting point / Task definition

The Wolfshoehe brick plant has been investing in automation for years, wherever it makes economic sense. For example, fireclay chimney pipes provided with tongue and groove joints were previously transported by linear units. Since this factory was being decommissioned, the company regarded the move to a new facility as a chance to modernize its handling equipment.
Implementation / Solution
Handling of grog tubes
Handling of grog tubes

Today the fireclay chimney pipes are handled by three KUKA robots, as a result of which productivity, quality, and flexibility have all improved. The robots used consist of a four-axis KR 180 PA palletizing robot and two six-axis KR 45 standard robots. The fireclay blanks are automatically cut to lengths of 330 or 660 mm. A group of four 330 mm long pipes and a short stacking ring make up a unit, which is later stacked into a tower by the KR 45s. When 660 mm long pipes are produced, two pipes and a stacking ring make up a unit. In the next step they are transferred to the transport troughs of the pipe production system. The system operator uses a control panel display to select the program corresponding to the length and diameter of the blanks. The robots are controlled using the KUKA Control Panel. In the case of 330 mm long pipes, two blanks are placed in each trough, alternating between pairs of pipes with and without a stacking ring, which are then moved to the pickup position. There the KR 180 PA picks them up using its vacuum cup gripper and places them in the troughs of the transverse pipe conveyor. This simultaneously feeds one blank each to the tongue and groove cutting stations on the left and right sides. The stacking ring, on the other hand, is tipped out onto the pipe conveyor. After the cutting process, the transverse conveyor brings the pipes to the two KR 45s. These robots pick up the blanks and stack them vertically one on top of the other on the stacking ring which is already located on the pipe conveyor. Since the stacking ring is mechanically located in a defined position, the KR 45s can stack the pipes with accuracy to the millimeter. In this process, the robot controller uses a laser sensor integrated into the gripper to monitor the remaining distance continuously. This information makes it possible to position the blank with great sensitivity. Once a pipe tower is complete, the conveyor advances it to a pipe pickup unit. This picks up the tower and transfers it to the furnace carriage. For 660 mm long pipes, the user only needs one KR 45 and one transverse pipe conveyor. Moreover, in this case the remaining six-axis robot always picks up only one blank, and the KR 180 PA adds a stacking ring in every second cycle.
System components / Scope of supply

  • One KUKA KR 180 PA palletizing robot
  • Two KUKA KR 45 robots
  • Three PC-based KUKA robot controllers, including control panel with familiar Windows interface
  • Three vacuum cup grippers which can be adjusted for various pipe diameters
  • Robot programming
  • Commissioning

Supplied by FREYMATIC AG, Felsberg, Switzerland.

Results / Success

  • Advantages of the “palletizing expert”

    The KR 180 PA “palletizing expert” is a four-axis robot with a passive fifth axis, whose application-specific, FEM-optimized kinematic system guarantees particularly efficient palletizing processes. Its arm is made of carbon fiber composite material (CRP), which thanks to its smaller mass moment of inertia provides truly remarkable acceleration rates. The KR 180 PA can stack loads weighing up to 180 kg to heights of up to 3000 mm. It was precisely this long reach which was the decisive factor for the user in selecting the right robot for the job. Another advantage of the KR 180 PA is its lower manufacturing cost compared to a six-axis machine. Additional cost savings are achieved through the extensive use of standard components.

  • Output increased significantly

    The conversion to robots resulted in a significant increase in output. The area of the Wolfshöhe brick factory where the robots are used now operates more than 50 percent faster than before. Furthermore, the company now requires much fewer employees in that area. The current production rate of 16 fireclay chimney pipes per minute is achieved thanks to the short cycle times of the robots, and the fact that the chimney pipes are provided with their tongue and groove not sequentially, as before, but in pairs at two parallel stations.

  • Higher quality

    In addition, the Wolfshöhe brick factory obtains better quality because of the robots’ high repeatability and their extremely gentle handling of the blanks, as a result of which there is no longer any deformation.

  • High flexibility

    Another advantage of the robots is their flexibility. This is demonstrated, for example, by the way they can handle five pipe sizes with diameters ranging from 120 to 200 mm.

  • Reduced personnel requirements

    Use of the KUKA robots means that the corresponding manual operations, as well as various transfer tasks, are no longer required. In this respect the user also benefits from reduced personnel requirements, a minimized error rate and shorter transfer distances. The user has also noticed a reduction in damage.
Number of report
R 222
Ceramics, mineral products
Handling, loading and unloading
Other handling operations
Medium payloads (30-60 kg)
Palletizing robots
KR C (Robot Controller)
Wolfshoeher Tonwerke GmbH, Germany

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