Fiber Orientation Characterized by the Relative Movement of Stock Flow to Wire

Stock flow velocity was measured with a jet velocity meter system in various operating conditions of industrial headboxes. Edge flow made the flow directions of both machine sides more inner, and side bleed made them more outer. Larger recirculation inclined the flow direction to the overflow direction. Slice opening profile affected the flow direction, too. These flow behaviours were reflected in fiber orientation of paper. Experiment was performed with changing the differential vector between stock flow velocity and wire velocity. It was suggested that fiber orientation of paper is mainly determined by the relative movement of stock flow to wire at J/W≠1 rather than by the fiber orientation in jet. Furthermore, the z-directional profiles of fiber orientation in x-y plane in papers made by commercial paper machines were measured by a newly developed method. The information of the differential vectors on sheet forming can be obtained from these z-directional profiles.