In many branches of industry such as the paper, plastics, textile and sheet metal industries, material in continuous, flexible strip form (web) is unwound or rewound before and after processing. A primary goal of web handling is to prevent tearing during all the handling processes. Accurate tension control is required to ensure that the material is wound without forming wrinkles or creases.
As an example an unwinder with one drive on the take-up roller, and another on the pull-off roller, necessitates a control element to balance the speeds of each drive unit. The pull-off roller usually operates in a speed-controlled manner. The material is unwound using a constant web speed. The winder determines the tensile force, while the speed signal from the pull-off roller functions as a control signal. In many applications, the drive for the pull-off roller is not necessary. It can be replaced by a master encoder that delivers the master signal for the winder.
With the Movidrive concept by SEW-Eurodrive, a wide range of functions can be used extensively and efficiently by accessing standard application modules and technology functions built into Movidrive inverter units, including standard IPOS plus positioning and sequence control. For example, for the winding application, the 'Centre tension winder' application is used. This user-friendly interface guides the user through the process of entering the parameters such as fixed diameter and tension must be entered. The application module turns this information into the control programme and loads it into the inverter.
Many winding machines measure the winding diameter to determine and set the correct winding speed. This measurement process can be neglected since the current diameter can be precisely determined through calculation by IPOS plus in the Movidrive unit. The 'Centre tension winder' application module offers the possibility of reducing the tensile force with increasing winding diameter. The winding characteristics can be set in accordance with any requirements.
However large the variety of applications for centre tension winders, the wide range of functions provided by the application modules in Movidrive have an appropriate solution for the task, including choice of fieldbus or terminal control, display of web speed and current diameter, counters for material length, and monitoring for material tearing.
For more information contact Carrina Davies, SEW-Eurodrive, 011 248 7000, [email protected], www.sew-eurodrive.co.za
| Tel: | +27 11 248 7000 |
| Email: | [email protected] |
| www: | www.sew-eurodrive.co.za |
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