Swiss food manufacturer Hero AG has installed three FANUC 6-axis robots fitted with customised grippers to handle the heavy and labour intensive task of palletising the company’s jams and preserves. Operating around the clock, the closed cell provides a fast, reliable and accident -proof alternative to manually stacking boxes of jam as they leave the assembly line.
Loading the jam pallets was a task previously undertaken by five employees at the manufacturer’s headquarters in Lenzburg. It was a tedious and backbreaking job getting the boxes stacked and ready for distribution. Now, three FANUC M-710iC robots are taking the load.
Behind the installation was local automation specialist Robotec, who designed and tested the closed cell and integrated its special gripping technology onto the three FANUC robots.
In order to increase productivity, the FANUC robots pick up two boxes already packed with jam simultaneously, turning towards the pallet and setting down the boxes within millimetre precision on the pallet according to the programmed stacking scheme. Because the jam is packed in various containers, from individual portions in aluminium pots used by the hotel trade to heavier glass jars, the gripper design had to be customised to accommodate different box weights.
It is a seamless operation. Once the pallets are loaded according to the specification, a signal is sent by the FANUC robot to the operator, who opens the cell and uses a pallet truck to remove the full pallet and place an empty one in position. The operative uses a hand-held device located on the cell exterior to select the appropriate stacking program. Each time the operative leaves the cell and the access door close, this is relayed to the hand device, whereby the next stacking program is selected and palletising resumes.
Rather than installing an overly complex touchscreen, an intuitive control panel with fewer buttons was created to assist Hero’s international workforce. It means that operatives don’t have to select or change programs on the robots. In addition, universally recognised colour codes – red button for stop, green for start – were adopted, and the control panel was modified to restrict key steps, for instance pallet change.
A firm grasp of the challenges
Forgoing vision technology meant that the Robotec design team had to customise the stainless steel gripper technology so that the end tooling stayed the same regardless of the size or weight of box being manoeuvred by the M-710iC robots. Robotec’s development engineer Daniel Bärtschi explains: “We chose a shovel shape with an integrated slide, which pushes slightly against the boxes when setting them down on the pallet, whilst the gripper shovel retracts.”
Although the FANUC robots installed by HERO have a payload of 70kg, when designing the gripper, Robotec also had to factor in the different box weights, the centrifugal force of the fast pivoting movement from the conveyor towards the pallet and also how foil packs still warm from the production line might behave when gripped and impact the palletising pattern. Daniel notes: “With the jam temperature transferring onto the foil, a box may become slippery during the gripping and transport process potentially resulting in a crooked stack which would need re-palletising.”
Commenting on the role that automation plays in reducing human hazards and the subsequent risk of product damage, FANUC UK’s regional sales manager John Rainer says: “Robots help to eliminate workforce injuries, especially on tasks like palletising which are repetitive and arduous. Equally, you need to keep operatives safe, and there are all types of technologies and safety concepts that can be deployed within the working envelope when automating a task. In the case of this Hero jam palletising application, it’s a typical caged solution. However, there is a wide range of reliable, approved software-based safety systems, including FANUC’s Dual Check Safety system (DCS), available to manufacturers today that have the potential to optimise productivity by providing faster, easier access to the robot working area, reducing any potential downtime.”
For further information about FANUC robots please visit www.fanuc.eu.