The scaffolding manufacturer MJ-Gerüst in Plettenberg produces scaffolding system components on ultra-modern special machines developed in-house. Schunk components are installed several times in an interlinked production line for the manufacture of long scaffolding tubes. In this specific large-scale plant with various handling and processing stations, all modules and processes are interlinked.

Clamping technology and automation are growing together

Almost 120 PGN-plus-P grippers are in action, around 25 EGM magnetic grippers and several lathe chucks. "We attach great importance to quality, robustness, stability and durability," emphasizes Jörg Brauhardt. "The repeat accuracy of the gripper is also very important due to the long components and the deflection. All components in the system must meet high requirements, because we need a reliable overall process." With 27 years of experience in design, he knows what is needed for the automation of the specific task. "This is a robust, rough business, it's safety-relevant, so we need quality here. Everything has to fit, it has to work and it has to last." A machine failure means the entire production line comes to a standstill because all stations are interconnected. "That can't happen, we have to rule it out," emphasizes Brauhardt. The raw material arrives in bundles by crane or forklift and is placed in the first station for separation. Each pipe is first automatically measured for length. It is then transferred by two robots, each with several PGN-plus-P grippers, to a pusher on which a Rota TP 200 three-jaw chuck from Schunk is installed. The pusher moves with the tube into a laser cutting cell. While the laser head positions itself, the tube is held in place and then rotated endlessly until the ends on the left and right are cut off. The laser cell stops rotating when the cutting is complete. "After the cutting station, the tubes are deburred, initially picked up in packs of two, transferred and fed on in bundles of three," explains Brauhardt. "The magnetic grippers with an adapted half-shell grip the pipes very tightly and close together. This prevents rattling and clattering at this point and protects the material."

Stations work hand in hand

For the next stage - marking with a serial number and article number using needle scribing - each tube is separated again. This marks each individual tube, which is important for the manufacturer during welding and storage. The marking is still visible after galvanizing and ensures the permanent traceability of the components. Finally, a pipe end is tapered via cold forming, which thickens the material and results in a highly stable pipe connection. The pipes are now measured again to zero point so that they can be gripped securely by the robot for the next and final process: Six tubes in a bundle are inserted into the final laser cell, where the tubes are perforated.

Six finished tubes leave the line every 60 seconds. Schunk components do their job reliably and in large quantities at every processing and handling station. The universal gripper PGN-plus-P is used in the system in both sizes 100 and 125. The proven and versatile parallel gripper has a high load capacity due to the improved multi-tooth guidance and offers maintenance-free, reliable operation thanks to permanent lubrication. "We have adapted the gripper jaws specifically to the pipe geometry at each station, depending on the handling situation," explains Jörg Brauhardt.

The EGM electro-permanent magnet gripper for energy-efficient handling of ferromagnetic workpieces also shows its strengths in this system. With its low weight and high dynamics, it handles the long material reliably. The workpiece accessibility without interfering contours enables a dense and gentle handling situation. Power is only required for magnetizing and demagnetizing. "The Rota TP 200 power chuck is also in the right place here," says the design manager. With the integrated clamping cylinder, a large through-hole is possible, which is ideal for tube machining. The chuck can also be operated at a standstill. Pneumatic power chucks from Schunk are a suitable alternative if the chucks are not to be actuated manually or via hydraulics.

The cycle time-optimized, interlinked system is designed for the future, assures Brauhardt. The gripper and clamping modules do what they are supposed to do. "This is top quality, nothing breaks." Thanks to the close cooperation and intensive discussions between the user and Schunk, the solution could be realized. Once again, the customer benefits from the fact that Schunk, with its extensive automation expertise, can provide suitable components for the respective processes. "In this system, the combination of clamping technology and automation is certainly unique," summarizes Jörg Brauhardt.