Since expensive production machines can be run in three shifts only if the automation is integrated, particular attention must be paid to the periphery and, above all, the gripping systems.
 
Schmalz is the world's leading partner for vacuum gripping systems in automation technology. Innovative and complete vacuum automation systems permit a smooth and fully automated material flow. The reduced set-up times result in shorter amortisation periods. Multifunctional palletising and depalletising systems ensure high productivity and availability, together with optimal utilisation of the available working area.

These and other benefits convinced Messrs. Cosack GmbH, specialists for innovative printing and packaging in Arnsberg, who were looking for a supplier to build and equip the material-flow and handling periphery for their production lines for folded cardboard boxes.

The general contract for implementation of a flexible material-flow and palletising system was awarded to Messrs. Bobst Group Deutschland GmbH, with their cooperation partner for automation, Messrs. FPT.

FPT, in turn, commissioned J. Schmalz GmbH with the design and manufacture of a multifunctional vacuum gripper. This gripper, mounted on an articulated-arm robot, grips the corrugated-cardboard boxes full of folded cardboard boxes, or the bundles of folded boxes, for transfer from the production lines to the pallets.

The problem:

• Rationalisation of the periphery of three parallel gluing lines for folded cardboard boxes.
• The cartons containing the folded boxes must be palletised fully automatically, including the insertion of intermediate layers of cardboard.
• Optimal utilisation of the pallets and thus of the available storage space.
• Short cycle times, high availability of the system and free access to the production lines.
• Products: corrugated-cardboard boxes and bundles of folded cardboard boxes
      Length: 200 to 700 mm
      Width: 180 to 400 mm
      Height: 200 to 480 mm
      Weight: about 3 to 25 kg (in exceptional cases 30 kg)
      Intermediate layers of cardboard:
      Size: 800 to 1200 mm 
      Grammage: 200 to 700 g

The requirements:

• Three-shift operation of the system (24 hours per day)
• Total output of the three lines: about 600 cartons (12 pallets) per hour
• Gripping time <1 s
• Release time <1 s
• Flexible adaptation to different corrugated-cardboard boxes or bundles of folded boxes

The solution:

The concept developed by Schmalz in cooperation with Bobst and FPT was a central palletising system which, thanks to modern robot kinematics, was very compact and space-saving.
The multifunctional griping system mounted on the articulated-arm palletising robot uses intelligent vacuum technology:

• It is extremely flexible and grips boxes of various sizes, bundled goods and the intermediate layers of cardboard with one and the same gripper.
• The goods to be packed and the intermediate layers are positioned quickly and precisely.
• High performance thanks to the use of high-tech control and drive technology.

The gripper:

• 6 parallel aluminium beams (length 600 mm, cross-section 40x40 mm)
• Each beam is equipped with six suction pads of the type FSGA 63 NBR with flow resistors (to maintain the vacuum even when some pads are not in contact with the workpiece)
• A total of 36 suction pads on six beams
• Plates mounted above the beams stabilise the workpieces to prevent them from swinging during high acceleration

• Vacuum generation and control
  o The gripper has three separate vacuum circuits.
  o Each of these circuits is provided with vacuum by a multi-stage ejector of the type SEM 100 and has its own compressed-air control valve.
  o The vacuum is regulated to suit the differing workpieces.

• Vacuum and system monitoring
  o Each vacuum circuit has its own digital vacuum switch (VS-V-W-D) in order to detect when its suction pads are in contact with a workpiece (part-present monitoring on the gripper).
  o If the pads of a circuit are not in contact with the workpiece, the circuit is deactivated.
  o This Intelligent control system reduces the consumption of compressed air and thus reduces the operating costs!
  

Customer benefits:

• High productivity thanks to short packing cycles
• Short gripping times and, at the same time, safe and reliable gripping
• No need to convert the system when orders are changed, since the extremely flexible gripper adapts itself to the differing workpieces
• Extremely careful handling of the goods thanks to vacuum technology
• 99% availability of the system
• Amortisation in three-shift operation within 1½  - 2 years