METHOD FOR ADJUSTING SHEET THICKNESS OF PLASTICS SHEET IN ROLL FORMING PROCESS BY AUTOMATIC CONTROLLABLE T-DIE

摘要

PROBLEM TO BE SOLVED: To obtain a high qualified sheet with a smooth and substantially uniform thickness even in an extremely thin sheet. SOLUTION: This adjusting method is such that the extrusion thickness is made via an aimed profile of the T-die to be controlled at width directional pitches (p) in a roll forming process. In this case, the aimed profile P is set In a thicker complex compensation type profile P than the one added by an uneven part compensation method in which the recess (a') in a central wall thickness part (section III) and a projection (b') in both the thin wall parts (section I and V) of the uneven parts (a), (b) between the further small pitches (p) are arranged at a thicker position (lower side) and thinner position (upper side) than respective ones, with respect to a roll curvature compensation type profile P' set to be substantially thick in its central part relative to both the side parts.