ASMAG - Anlagenplanung und Sondermaschinenbau GmbH

Multi-roll strighteners for tubes

ASMAG, Austria, a supplier to the steel and non-ferrous metals industry, has developed a unique, new generation multiroll- straightening machine for steel tubes for Wiederholt GmbH, Germany.
The 10-roll-straightener – branded type RRM-pro 125/420/10 – is working up to a maximum tube outside diameter of 125mm and line speed of 180m/min.
To achieve the best accuracy in straightness, a new drive system was developed to reduce the roller centre distances to an absolute minimum. Moreover the individual high efficiency AC servomotors enable roll wear compensation and high dynamic process control.
A further feature of the machine is the identical design of the vertical and angular adjustment of all ten rollers. In association with additional adjustments on the inlet and outlet troughs the 1st and the 5th pair of rollers can be fully integrated in the tube bending/ovalisation process. The centreline of the machine can be changed.
The vertical adjustment of each roller is performed by hydraulic cylinders controlled by servo valves; each roller is limited in load by limiting the pressure in the hydraulic cylinder. Together with direct measuring by absolute encoders, clearances in the system are eliminated.
With the new straightening mode ‘Realtime Setting’, adjustments are not restricted to the time period before and after a cycle.
This mode has already been proven on the ASMAG 2-roll-bar straightening machines and allows adjustments during the straightening process in real time.
This mode also enables different settings for tube rear end, front end and the remaining tube if necessary. For this purpose the drives of the high dynamic controlled vertical and angular adjustments of the rollers are designed and calculated to suit the most challenging straightening loads.
ASMAG’s aim was to establish the pioneering technology of tube straightening machines, which meets with ASMAG’s general philosophy in developing its machines.
Mr Johann Vielhaber, managing director of ASMAG, commented, “As a leading supplier it is our challenge to set new standards in tube processing.”
The straightening machine is part of a fully automatic drawing line for welded tubes, incorporating pointing, drawing, tube rear and front-end cutting, straightening, ultrasonic/eddy-current testing and multiple cutting equipment.