Comprehensive automation part 1

de Man develops palletizing system for flour sacks: For the SchapfenMühle, de Man Automation + Service GmbH & Co. KG has developed a flexible palletizing system for sacks with flour and wholemeal. The challenge was the great variance in the dimensions and filling levels of the sacks, which are now perfectly stacked by a specially developed gripper. The project was only the first of three stages of extensive automation for the customer. In the next step, de Man delivers another palletizing system and then a comprehensive pallet conveyor system including pallet winder and labeler, which takes over the automatic removal of the finished pallets from the two systems.

SchapfenMühle GmbH & Co. KG is a traditional mill company from Baden Württemberg that specializes in spelled products, baking mixes and health food. Bags should be palletized with flour, wholemeal and peeling products, which differ not only in size and weight, but also in the degree of filling. The dimensions vary in length between 480 and 950 mm, in width between 225 and 480 mm and in height between 120 and 190 mm. The weight is 10 kg (flour) or 25 kg (flour / wholemeal / peeling products). The fill levels range from lax to tight. A wide range also had to be taken into account when it came to the pallet types used: the mill used EURO pallets, H1 hygienic pallets and container pallets. The specified output for the flour and wholemeal products was a maximum of 560 bags per hour and for the peeling products a maximum of 480 bags per hour. In addition to the large variety of products to be palletized, the small amount of space and the low ceiling height had to be taken into account.

Bottom layer magazine with handling
In the first stage of the extensive project, a palletizing system with two pallet magazines, a bottom layer magazine and a pallet lifting station was created for the SchapfenMühle by de Man. The entire facility extends over a length of almost 13 meters, a width of 12 meters and a height of approximately 3.75 meters. The two pallet magazines (one of them with a buffer space) each have a capacity of 15 pallets and are filled manually with an electric pallet truck. The width can be adjusted to accommodate the different types of pallets. A transverse carriage takes the empty pallets from the pallet magazine and transports them via a pallet conveyor to the floor layer magazine, which holds a EURO pallet with cardboard floor layers. With the help of a handling system, a bottom layer is removed from the stack and placed on the empty pallet. This is then transported from the transverse carriage to the buffer area of ​​the robot cell and, if necessary, to the palletizing area. The long construction of the entire system is due to the next step of the project: The second palletizing system will be positioned exactly between the two pallet magazines and the first system, so that the magazines supply both systems with pallets via the conveyor line. Before that, two new filling lines for flour and peeling products were created on the customer side, which would then each serve one of the two palletizing cells.

Suspended from the ceiling
For the feeding of the bags, an ascending conveyor and a leveling belt (both already on the customer side) were integrated into the system. The entire feed had to be suspended from the ceiling for space reasons. The bags are taken over by the ascending conveyor by means of a swivel conveyor, rotated 90 degrees and conveyed to the leveling belt with the bottom ahead. A conveyor belt now takes over the sacks and transports them with a curve to the pick-up point in the palletizing cell, from where they are conveyed on a roller conveyor to the end stop. The robot - a KUKA KR120-R3200 with 4 axes was used - now stacks the sacks on the empty pallet in the palletizing station. In order to transport the different sized and heavy bags safely, the specially developed gripper has an upper and side pressure plate in addition to the gripper fingers. The maximum width of the gripper can be set manually using a handwheel.

Lowering the finished pallets
The finished pallets are transported to the pallet delivery area, which is designed as a lift. Here they are lowered from a height of 500 mm to 80 mm and then removed with a hand pallet truck. The travel area of the cross conveyor, the bottom layer magazine and the palletizing station are surrounded by a protective fence, access to these parts of the system is via protective doors. The safety interlock with guard locking only allows the protective doors to be opened when the dangerous movements are safely stopped. In the course of the implementation of the 3rd stage of the project, both palletizing cells are connected to the higher-level ERP system "Navision", from which they receive all order-related data (pallets, palletizing schemes, winding programs, label data). A regular exchange of production, performance, order and master data for all items then takes place between the systems and "Navision".