Hiromu Suzuki

Study of Precision Rolling Mill

A 6-high, 3-tandem precision rolling mill was designed and manufactured for a specific purpose of rolling the coelinver for power spring of wrist watches, at the required precision in thickness of product within ±1 μ at 0.1mm thickness. Special attentions were paid for the satisfaction of the requirements, namely, (1) the elastic deformation of the housing and rolls of rolling mill during rolling must be small, (2) the tension imposed upon and the speed of motion of the material must be automatically controlled with accuracy, (3) major parts of the mill must be finished as precisely as possible, (4) a number of pairs of AC motors and hydraulic torque converters must be employed as a power source.An excellent yield of 98% was obtained at the practice run by the trial mill manufactured on the principles described above.In the present report, the structure of the mill and the partial results of experiments obtained by the mill are discussed.