The reliability and throughput on a hot-plate production line at Slovenia’s leading foundry has been improved with the installation of 36 axes of servo control.
The bending and welding production line at ETA Cerkno was suffering from reliability problems and unacceptable levels of downtime. Breakdowns meant that bending or welding had to be carried out manually, a costly exercise. Availability of spare parts was a further issue, while replacing the six machines was prohibitively expensive.
“The mechanical side of the machines was fundamentally good,” says Marko Vrabl, manager of PS Logatec, Control Techniques’ local drive centre, “and so ETA brought us in to upgrade the electrical control system. In four of the six production cells there is a three-dimensional wire bending machine and a four-dimensional SCARA robot for assembling and welding the wire contact onto the heating plate. Two other cells have just a SCARA robot. Before the retrofit, the program was written in a low level language and was loaded from a PC that was wheeled between cells as required.”
According to Vrabl the system is now much easier to program and use. Each cell has its own control cabinet complete with seven Unidrive SP AC drives working in servo mode and with a position controller and touch screen terminal. To program a bending machine is now a simple matter of keying in a set of parameters. Each cell has a high level of security and safety, with power immediately turned off if the door is opened.
The robot is programmed using a teach-in feature on the Unidrive SP drives. This has proved very popular with ETA. An operator is able to go safely into a cell and, using just a 48 V power supply, drive through all of the robot axes using a handheld control unit. This rehearses all the movements and actions that are needed. Then, when the operator is out of the cell and the door is secured, the full power can be restored and the robot is ready to go.
Unidrive SP is a ‘solutions platform’ AC drive which is configurable into open and closed loop, vector, servo and regenerating modes. It has connectivity to most industry standard networks, is configurable for all types of AC motors including linear motors, and accepts 14 position feedback protocols.
For more information contact Control Techniques, Bianca Botha, +27 (0)11 462 1740, [email protected], www.controltechniques.co.za
| Tel: | +27 11 462 1740 |
| Fax: | +27 11 462 1941 |
| Email: | [email protected] |
| www: | www.controltechniques.com |
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