A non-circular turning system to minimise roll geometry errors

Increased running speed and the reduction in accepted vibration levels in paper machines have set new demands for the roundness and cylindricity of paper machine rolls. The diameter variation is mailny caused by the slideway straightness error of the machine tool. The rotational errors during the machining process come about because of the changing distance between the roll centre axis and the tool and are copied to the roundness error in the roll. A 3D turning system, including a measuring device, was developed to compensate systematic roll geometry errors. In this study, the non-circular turning method was applied to a supercalender roll. The 3D turning reduced the average roundness error in the test roll by 62 %. The diameter variation in the axial direction was reduced by 83 % and the 3D geometry error by 78 %.