Complex task mastered

The construction industry needs a lot of hard-working hands. In many areas, manual work is still the norm. Terhoeven GmbH & Co. KG has now tackled a typical example - the monotonous and strenuous cutting of steel mesh. The medium-sized mechanical engineering company relies on drive and automation technology from Mitsubishi Electric. The result is an innovative system that is not yet available on the market.

Challenge: Separating and lifting the mesh is complex

ASA (automatic cutting system) is the name of the newly developed machine that handles, cuts and stacks the steel mesh fully automatically. Lifting the top mesh from the stack is a major challenge, as the manufacturing tolerances of the steel mesh are in the centimeter range, but handling requires an accuracy of less than a millimeter. In addition, the individual meshes do not lie neatly in the stack. This is why 3D image processing is used, which identifies six suitable pick-up points. When the grippers lift the mesh, the next challenge arises: the mesh bends. Therefore, three separately operating drives are required for each of the six points in order to be able to move the grippers in all three spatial directions. During operation, the drives must be controlled precisely and synchronously.

Solution: drive and automation technology from a single source

In order to compensate for the deformation of the mats during lifting, 18 drives are required for the hoist, plus four drives for transporting the mats within the system. Servo drives from Mitsubishi Electric with the corresponding servo amplifiers are used here. The motors of the MR-J5 series are very compact and offer high dynamics. The appropriate servo amplifiers can be coupled via intermediate circuits, which contributes to the high energy efficiency of the system.

The motion controller enables the required synchronization of the drives to be optimally implemented. All other components of the automation technology also come from Mitsubishi Electric. FR-E800 frequency converters are used for simple conveying tasks. And a safety PLC from the MELSEC iQ-R series controls all processes in the system. This is supplemented by three C controllers on which the image processing runs. CC Link IE TSN is used as the protocol, which enables not only real-time capability but also the necessary safety-related communication. With the gigabit bandwidth offered by the open standard CC-Link IE TSN, the communication of control, motion control and safety can be easily integrated into a network.

Result: Huge system can be operated by one person

After a development period of almost two years, the first six-meter-high and over 40-meter-long ASA was put into operation in spring 2024. It is operated using a GOT control unit from Mitsubishi Electric. In addition to the touchscreen, however, some buttons and switches are also integrated to make it easier to operate with gloves. Converting the system, for example to a new mat size, is very easy with the GOT control unit. Only a few activities have to be carried out by hand during setup. In routine operation, the system can then be operated by one person.

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