MODIFICATION AND UPGRADE OF MILLS

Mill upgrade (steel mill):
Strip thickness up to 14 mm
Strip width up to 2000 mm
Total roll force 3000 t
Vollmer supply:
Hydraulic power unit and
control cylinders, AGC

The condition for a high speed strip thickness control is the fast and precise screwdown of the rolls. Fast means just a few milliseconds and precise means an accuracy of lass than a µm.

Vollmer has the experience of decades in replacing spindle-motor screwdowns in existing mills with servohydraulic mill screwdown, in designing the new cylinders per the space in the mill, in designing and planning all hydraulic power units and in modifying the mill on site (anywhere in the world).

1. The new cylinders are unpacked
2. Hydraulic power unit, 2 pumps on a motor shaft
3. Valve stand on the mill

The efficiency of the servohydraulic mill screwdown is the necessary basis for the success of the high speed strip thickness control.

The hydraulic cylinders must move to the nominal position with a sufficiently low friction and highest speed (3 mm/sec). The position is controlled by high-resolution position sensors (0,2 µm).