JPH05237717

PURPOSE:To realize stable side trimming without burrs even in high speed by determining a cutter position from the thickness of a material to be trimmed, the position of the upper surface of the material in the trimming time and a result of measuring the diameter of a cutter in the trimming time to correct the cutting quantity of the cutter. CONSTITUTION:Both edges of a metal strip 1 is notched by a side trimmer 3 to a predetermined cutting quantity leaving the uncut portion and the notched portion is nipped by upper and lower opposed push-back rolls 7 in the direction of the thickness of the metal strip to cut off the uncut portion. Then, the thickness of trimmed portion of the metal strip 1, the position of the upper surface of the trimmed material in the trimming and the diameters of trimmer cutters 3a, 3b in the trimming are actually measured, so that the cutting quantity (a) of the trimmer cutters 3a, 3b is corrected in real time. As a result, slitting without burrs can be stably carried out even in high speed running.