Shape Control in Cluster Mills

Cluster mills first came into existence in the 1930s. They are characterized by small-diameter work rolls that are supported by a cluster of rolls as shown in Figure 1 (which shows the location of eight backing assembly shafts: “A” through “H” containing eccentric saddles and bearings). More than 600 cluster mills are now operating around the world. Of these, approximately 400 are of the Sendzimir type, in which, with few exceptions, the housing is monoblock with very short columns and rigid construction, resulting in a high mill modulus (stiffness).