The world's first fully automated line for reinforcing steel mesh

ASA (automatic cutting system) is the name of the newly developed machine that handles, cuts and stacks the reinforcing steel meshes fully automatically. Lifting the top mat from the stack is a major challenge, as the manufacturing tolerances of the structural steel mats are in the centimeter range, but handling requires an accuracy of less than one millimeter. In addition, the individual mats do not lie neatly in the stack. For this reason, 3D image processing is used to identify six suitable pick-up points. When the grippers lift the mat, the next challenge arises: the mat bends. Three separate drives are therefore 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.

To compensate for the deformation of the mats during lifting, 18 drives are required for the lifting gear, 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 from the MR-J5 series are very compact and offer high dynamics. The appropriate servo drives can be coupled via intermediate circuits, which contributes to the high energy efficiency of the system. With the motion controller, the required synchronization of the drives can be optimally implemented. All other automation technology components also come from Mitsubishi Electric. FR-E800 frequency inverters are used for simple conveying tasks. And a safety PLC from the MELSEC iQ-R series controls all the processes in the system. This is supplemented by three C controllers on which the image processing runs. The protocol used is CC Link IE TSN, which enables real-time capability as well as the necessary safety-related communication. With the gigabit bandwidth offered by the open CC-Link IE TSN standard, communication between the controller, motion control and safety can be easily integrated into a network.

After a development period of almost two years, the first six-metre-high and over 40-metre-long ASA was put into operation in spring 2024. It is operated via a GOT control unit from Mitsubishi Electric. In addition to the touchscreen, a number of buttons and switches are also integrated to facilitate operation with gloves. Converting the system, for example to a new mat size, is very easy with the GOT control unit. Only a few tasks need to be carried out manually during set-up. In routine operation, the system can then be operated by one person.