140 percent more productivity

Jörg Monsig, plant manager at Lang Metallwarenproduktion Neubrandenburg GmbH, is looking for the weak points. The goal is to optimize production in order to remain competitive and an attractive employer. "We want to create modern, intelligent and networked workplaces," Monsig explains. Back in 2013, he introduced a company health management system and optimized various work processes according to ergonomic aspects. Now the task was to automate the assembly of a spot welding system and thus increase productivity and workplace safety.

Lang Metallwarenproduktion Neubrandenburg GmbH can look back on a long tradition: The parent company, Lang und Vertriebs GmbH, based in Munich, has been manufacturing and assembling stamped and drawn parts for over 60 years. It started with chrome components for the automotive industry. the company moved1992 into new production premises at the Woldegk site in southeastern Mecklenburg-Vorpommern and founded Lang Metallwarenproduktion Neubrandenburg GmbH. Today, the approximately 50 employees manufacture stamped and drawn parts mainly for the automotive industry - from stainless steel and all common metals in small quantities up to large series.

"We always look to see where we can avoid monotonous manual tasks," says Jörg Monsig, pointing to a yellow robot separated by a protective fence. The robot picks up sheet metal parts from a turret table. Until six months ago, a worker stood here. He took a stamped and bent part, loaded it into the spot welding machine, which joined it to an automatically fed nut. After joining, he inspected the joint. "Monotonous work tends to lead to a higher reject rate," the plant manager points out. What also bothered him was that only one person could work on the system, which limited output.

The people responsible from Woldegk wanted to change that and directly started an R&D project with support from the European Regional Development Fund. Their automation requirements: "A robot was to pick up the components from above and separate them. For this, we needed a gripper that enables high cycle times and can accelerate to five meters per square second," says Monsig.

A mechanical gripper solution proved to be a technical dead end: It would fail when it came to separating the thin stamped and bent parts measuring 150 x 150 millimeters and weighing 500 grams. A pneumatic variant would face completely different challenges: The gripping surfaces are limited due to engravings, holes and the three-dimensional geometry and lie in different planes. "An off-the-shelf solution seemed difficult to us," describes the plant manager. But not for the vacuum experts at J. Schmalz GmbH: "Jörg Monsig and his team needed a gripper for robotic automation that was specially tailored to the particular geometry of the sheet metal parts," recalls Dr. Florian Fritz, Head of Business Development Process Vacuum Systems at Schmalz. For the vacuum experts, the solution was therefore obvious: The lightweight gripper SLG can be individually adapted to the sheet metal parts - without any design or manufacturing effort for the user. Using the STL file of the bent stamped part, Monsig was able to configure the gripper online and assemble it just a few days later. "In order for us to deliver custom-designed and automation-engineered grippers in such a short time, we use 3D printers. Additive manufacturing technology not only reduces weight, but also interference contours, as the air guide is integrated right into the end-of-arm tool, eliminating the need for a separate hose guide," explains Dr. Fritz. Economical operation was also crucial: the gripper holds the component for a long time - during pickup, during the welding process and the quality check until it is put down. "The SCPSi compact ejector meets these requirements with flying colors," emphasizes Dr. Fritz, adding, "Thanks to its eco nozzle technology, the SCPSi achieves a high suction capacity with minimized compressed air consumption. This can be reduced by up to 80 percent thanks to the integrated air-saving function. "

The new system has enabled the automotive supplier to optimize its material flow. An employee stacks the bent stampings on the turret turntable while standing at a safe distance from the robot and the automatic welder outside the safety fence. The robot picks up the parts one by one from the table and holds them in the spot welding machine. Piece by piece, the table lifts the stack so that the robot can always remove the part from the same position. The welding gun closes and joins an automatically fed nut to the bent part using resistance spot welding. The robot holds the component securely during the process and then guides it in front of a camera, which checks that the connection is correct. It then drops the component onto a conveyor belt.

Lang Metallwarenproduktion benefits from the Schmalz solution in several ways: "Our productivity has improved by 140 percent," describes Jörg Monsig. In addition, process reliability has increased significantly. "The system is running smoothly. Within six months, we have welded 180,000 components without any malfunctions." The employees have also accepted the system very well. "We have been able to clearly improve working conditions and the activity has become safer. Cumbersome manual tasks have been eliminated, and the performance of all the people involved has increased - an important aspect in view of demographic change. We are very satisfied with this solution," Monsig sums up. There is also much praise for Schmalz's service. "The delivery took place only a few days after the order and the system was quickly installed on site. Afterwards, we went straight through."