Handling of animal fodder sacks

Starting point / Task definition

BASF was looking for an automated palletizing solution for its vitamin A concentrate, which is used primarily in animal food, but also in food for humans and in pharmaceutical products. The main reasons for this conversion from manual to automated handling were a desire for higher productivity and better working conditions for employees.

Implementation / Solution The automated system is built around a KUKA KR 125 six-axis robot equipped with a fork gripper. A decisive criterion in the selection of this automated system was the floor space requirement. The space which was available was relatively small, and was also not very high. During handling operations, only three centimeters remain between the top of the robot and the ceiling when the robot reaches its highest position.

Originally BASF had planned to use a palletizing machine, up until then the standard solution for such applications. The major argument against this, however, was its height requirement, which would have necessitated constructing a pit. Besides the additional expense this would have involved, such a design would have been questionable from a food technology point of view, if only because of the difficulty and expense of cleaning. Additional arguments in favor of the robot were its short cycle time and good figures with respect to repeatability and flexibility.

The vitamin A is put into 25 kg sacks. When preparing shipments that will be sent overseas, BASF additionally places each sack in a cardboard box. The sacks and boxes are carried on conveyor belts through a weighing and labeling station before arriving at the robot. Just before reaching the robot, the goods are transferred from the conveyor belt to a roller conveyor. In this way, the vision system can report to the KR 125 that a container has arrived, and the robot can reach between the rollers of the conveyor with the forks of its gripper, and lift the sack without damaging it. The robot then gently stacks the bag on a pallet, which is located on the outgoing roller conveyor. The robot can also handle cardboard boxes using the same fork gripper that is uses for the sacks.

System components / Scope of supply

KUKA KR 125 robot
PC-based KUKA robot controller, including control panel with Windows interface
Fork gripper
Incoming and outgoing conveyor systems
Safeguards
Weighing and labeling station
Robot programming
Test setup to verify system functions at an early stage
Commissioning

Supplied by KUKA systems partner Koch-Industrieanlagen GmbH, Dernbach near Dierdorf, Germany.

Results / Success

High repeatability

The high repeatability of the KR 125 means that it can handle the sacks and boxes gently and stack them precisely, which plays a large part in preventing transportation damage.

Remarkable flexibility

Thanks to the robot’s flexibility, the user can switch quickly at any time between different container forms and stacking patterns. For example, the robot “knows” how to make composite stacks of sacks and column stacks of cardboard containers. Compared to a conventional palletizer, which sometimes actually has to be modified in the case of varying containers or conditions, with the KR 125 all one has to do is choose the appropriate program from those stored in the robot controller. To simplify this procedure even further, BASF had a lever installed which makes it even easier to select either one of the two standard programs, even if the operator has practically no prior knowledge of the system. Other programs are also provided, for example for varying the number of layers depending on the forwarding route.

Short cycle time

At a cycle time of ten seconds, the KR 125 stacks approximately 30 tonnes of vitamin A concentrate per shift. The capacity of the system is designed for growth, and a cycle of seven to eight seconds could be implemented. The gain in productivity from using a robotic cell becomes apparent if one considers that palletizing one sack previously took a whole minute.

Rapid payback

Since the introduction of this automated palletizing system, BASF has required two fewer workers in this area, thus achieving a relatively short payback period. The high availability of the robot is also important here; BASF is reinforcing this by sending some of its own employees for training by the KUKA systems partner.