When the roll is thicker, larger diameter tube or workpiece with stronger material strength, lower the driving roller a small amount each time. Molding is carried out in a small number of times.
When the roll roll is thick, the diameter is larger or the material strength of the workpiece, each time a small amount of the active roll. It is molded in a small number of multiple ways.
When rolling thick and large diameter cylinder or workpiece with high material strength, a small amount of active roll is lowered each time. A small number of times to form.