The customer is a well-known German manufacturer of baking tins for the “Gugelhupf”. The baking molds consist of a deep-drawn body and an inner conical tube. These are connected to one another by a fold that is applied in a forming tool.
Up to now, the production was only partially automated. The circular sheet metal blanks were automatically fed to a hydraulic press that deep-draws the baking mold body. The deep-drawn body was removed from the tool with a gripper and fed to a second hydraulic press that was equipped with a cutting tool and trimmed the edge of the formed sheet metal body. Another gripper has removed the trimmed body from the second press and fed it into a third hydraulic press by the use of a conveyor. An employee at the third press then inserted the conical tube and the deep-drawn body into the hemming tool by hand. Next, the press was triggered manually to connect the conical tube with to the deep-drawn body and roll in the baking pan edges. The finished baking pan could then be removed manually by the employee.
The entire process from loading the first press to removal by the employee on the third press had a cycle time of 16 seconds. The rolled and folded conical tube had to be precisely positioned by hand and placed in the hemming tool, as the bulging fold would otherwise get stuck in the tool during the connection process of the deep-drawn body and the conical tube. If such a malfunction occurred, the entire tool had to be removed from the press to free the stuck parts. This disruption lasted approx. 45 minutes until the production line was up and running again.
Due to the increasing number of parts and the requested delivery times, the customer decided to implement a fully automatic press line without manual intervention.
The customer's specification was a cycle time of 7 seconds and the fully automatic joining of the deep-drawn bodies and the conical tubes using a total of 8 different baking pan variants.
B + R GmbH has solved the concept as follows:
Three new hydraulic presses with different press forces were installed in line. The stacked sheet metal blanks are removed from the blank magazine with a vacuum suction system and fed to the first press for the deep-drawing operation. After each time the press has been lifted, a pneumatic linear axis system with a vacuum suction device removes the deep-drawn mold body from the tool of the first press and feeds it to the fixture of the second press. In this second press, the deep-drawn body is trimmed. After the stroke, a 3D-printed special vacuum gripper removes the trimmed deep-drawn body and places it into a station that centers the part. A gripping system specially developed by B + R GmbH removes the centered deep-drawn body and puts it into position at an angle of approx. 10 °. The preformed and folded conical tube is removed from a magazine stack located in a bypass using a 6-axis robot with a gripping system. Since the position of the fold on the conical tube is arbitrary due to the preliminary process, the gripped conical tube is rotated past a contactless sensor to determine the exact position of the fold on the tube. With this information, the conical tube is placed into a cup of the joining station and connected to the deep-drawn body. A gripper removes the joined parts and places them in the hemming tool of the third press by means of a pneumatic linear axis. After the press has been lifted, the finished Gugelhupf baking pan is removed from the tool using another specialized gripping system. Finally, the parts are fed to a conveyor line and conveyed out of the automatic press line.
The benefits for the client:
After completion of the fully automatic press line, Gugelhupf baking tins are reliably manufactured in large volumes at a cycle time of 7-seconds and without any disruptions.