Valmet-ahlstrom Inc.

Jarmo Kurki

The invention is related to a method for adjusting the knife clearance in sheet cutters. In a sheet cutter, the web material is cut by means of a cutter drum (1) rotated by drive mechanism (4) and provided with cutting knives (2), and a counter knife (5) disposed in a knife support (6) and positioned at knife clearance distance from the moving cutting knives (2). In the method according to the invention, the cutting forces acting on the cutting knives of the sheet cutters, or their effect on the structure of the sheet cutter during its operation, are measured, and the information from the measurement is used as a command variable for the knife clearance. The command variable can be determined in several different ways, and according to one embodiment of the invention, it is determined by measuring the vibration level of the structure of the sheet cutter due to the cutting forces. The invention is also related to an apparatus for carrying out the method.

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Karhula, Finland

Jarmo Kurki