Design Optimization of a Decurler for Sheet-Fed Presses.

The program carried out to develop an optimum decurler for sheetfed presses is described. Although the principle of employing a vacuum pump and an inversely formed bar or on-press decurling was invented in the 1950s, little or no data was available for design optimization. Consequently, it was necessary to run tests to confirm the relationship between paper curl and decurler bar geometry, which had been deduced from theoretical considerations. This test data was then used to establish the optimum bar geometry. A second phase of the program entailed optimizing the vacuum system so as to enable a given press system to be used over a wide range of paper widths. This phase consisted of tests aimed at optimizing the flow area of the bar and of determining the optimum match of the pump and the bar. The paper describes all of the tests which were run, together with the design recipes that were formulated and the actual equipment design which resulted.