Apparatus and method of determining sheet shrinkage or expansion characteristics

摘要

A method for determining the cross-machine shrinkage or expansion profile of a travelling sheet produced in a sheetmaking machine between an upstream location and a downstream location. The method involves marking the sheet at the upstream location with an array of marks at measured, predetermined intervals in the cross-machine direction. The sheet is inspected in the cross-machine direction at the downstream location to measure the spacing of the array of marks. A shrinkage or expansion profile of the travelling sheet is developed based on the changes in the spacing between the array of marks at the downstream location. Apparatus for carrying out the method is also disclosed. The method and apparatus of the present invention permit rapid and precise determination of the sheet shrinkage or expansion profile to allow for better control of property variation across the sheet.