STRIP SHAPE MEASUREMENT

Shape as a quality feature
In the past, the strip thickness tolerance was the essential dimensional quality criterium for strip material. Today, it is a necessity that the strip thickness tolerance satisfies the highest demands. Mills which do not satisfy this criteria, are upgraded immediately.

In addition, the strip shape has become an equally important characteristic in judging the overall strip quality.

The measurement of strip shape in operation has become easy! Even though the measurement systems are very complex, their application is almost invisible for the customer. The strip shape is measured with shapemeter rolls that are installed into the mill in place of the existing deflector rolls. The diameter and body length of the shapemeter rolls correspond exactly to those of the original deflector rolls and the bearing of the shapemeter rolls also corresponds to the bearing of the deflector rolls.

The advantages are obvious:

• No additional space required for the shapemeters
• No effects on the strip passline

While the strip is pulled over the shapemeter rolls, a variety of discreet measurement zones measures the strip tension distribution. At the same time, the monitor indicates the desired shape for the current strip. If the mill has the suitable control components, the shape is controlled in accordance with the requirements of the end customer (refer to Strip shape control).

An important factor for the design of the shapemeter rolls is the selection of the number of measurement zones for the rolls. The more measurement zones, the more precise the detection of the shape profile, but also the more expensive the measurement rolls. Our experts will be glad to give their advice at any time, based on decades of shape measurements on running strip material in mills of all types and on strips of all materials.

Vollmer offers three different types of shapemeter rolls:

• The roll with piezo force sensors
• The roll with transducers
• The roll for tension levellers