Identification of Sheet Hole and Defects in Newsprint Mills, 1997 Newsprint Forum Proceedings

Sheet holes and defects are a major quality and productivity problem in the paper industry. Emphasis is placed on this sheet quality problem because of the increased use of recycle, the demand for high quality sheets (zero defects), the increased installation of hole detectors, and the economic climate. A ten-step problem solving methodology is presented to help identify the problem, study the process, list and identify root causes, and select solutions and controls. A flow chart is used to demonstrate the ‘hands on” procedure for collecting and observing sheet samples. The examination with a high intensity light, viewing under a stereoscope, and testing the sheet defect with a spot test kit are also described. The process of sheet and hole identification shows that each sheet hole defect has a distinction which usually indicates the approximate location of its origin within the paper-making processes. The common mechanical problems that contribute to sheet defects, and the paper-making process areas to inspect if the sheet defect is caused by contamination are discussed. The objective of the sheet hole and defect procedure is to help the papermakers identify and solve their sheet defect quality problems in a timely fashion...