State-of-the-art production systems have long been part of everyday life at Gustav Hensel, a manufacturer of electrical installation and distribution solutions. However, the medium-sized company from the Sauerland region recently took its first steps in automation with collaborative robots (cobots) - and successfully so: with the help of a robotic arm from Universal Robots (UR) for palletizing packaged cable junction boxes, the family business is increasing its process efficiency and at the same time freeing employees from this physically demanding task.

The medium-sized family business based in Lennestadt has always strived to set new standards in the field of installation technology. To this end, the company employs around 550 people in Germany to develop and manufacture electrical installation and distribution systems.

In order to keep product quality high and remain competitive in the face of global competition, the company manufactures according to the lean principle: with a keen eye for detail, Hensel identifies every type of inefficiency along its entire value chain. Christoph Kaiser, Head of Plastics Production at Hensel, knows that it is crucial to deploy the workforce specifically for high-quality activities: "We have the ambition to be market leaders as well as to produce largely at our home base. This is only possible if we automate."

Robot frees up personnel capacities

In the production of cable junction boxes, huge amounts of man-hours were spent every day on palletizing packaging units. There was potential for optimization here, Hensel thought, and shortly afterwards became aware of the collaborative robots from Universal Robots at a trade fair. They met the company's clear requirements: the palletizing robot had to be able to be accessed directly at all times and a combination of reach and payload had to be optimally adapted to the packaging system. Kaiser adds: "Our aim was not to replace employees, but to create more capacity for higher-value activities. In terms of the lean concept, manual packing and bundling of the cartons did not add any value at all."

UR partner Dahl Automation designed the suction gripper for the robot arm so that it can flexibly handle bundles of different sizes. © Universal Robots

Together with UR partner Dahl Automation GmbH, Hensel launched the "First Cobot" project in spring 2017. Due to its payload capacity of 10 kg and its reach of 1.3 m, the company opted for the largest robot model from Universal Robots: the UR10. "When the robot has to place the packaging units right at the bottom of a pallet, its extensive working radius is extremely important," explains Kaiser. The handling of its risk assessment also played an important role in the implementation of the UR10. After this was successfully completed with the support of Dahl Automation, the robot arm is allowed to work in the immediate vicinity of its human colleagues without any protective housing. The basis for this are the patented safety systems of the Danish robotics pioneer. Overall, the integration of the UR10 at Hensel only took a few days, which is partly due to the professional preparation by Dahl Automation. André Gödde, Sales Manager at the UR partner, reveals: "Before we put a robot arm from UR into operation at our customers, we put the application through its paces in our own factory. This allows us to react quickly if, for example, motion sequences need to be optimized." On average, installation at the customer's premises is completed in one to two days.

Robot "James" moves 2.5 tons per shift

At Hensel, the UR robot works in two-shift operation as the last component in a complex, fully automated system consisting of assembly and packaging machines for the production of cable junction boxes. Equipped with a suction gripper custom-made by Dahl Automation, it palletizes around 1,200 packaging units per 8-hour shift. To do this, the system provides the robot arm with the packaged products in two boxes at a time. In a first step, the UR10 picks up the two packages and places them in a strapping machine. Once it has placed another pair of packages there for bundling into a four-unit, the machine straps them. The robot arm then stacks the cardboard bundles on a Euro pallet. "The UR10 lifts just under 10 kg during this last process, which means we make full use of its load capacity," explains Kaiser.

To further increase efficiency, Hensel provides the UR robot with two Euro pallets. When one of them is full, the UR10 automatically continues stacking at the other pallet location. Kaiser is satisfied: "The employee then only has to move the full Euro pallet out, prepare the next one for the UR robot and continue. This allows us to achieve perfect utilization of the application overall." Furthermore, the robot arm can be reprogrammed for different package sizes in the system in under three minutes with just a few clicks. It can move four different carton sizes as required.