| 摘要 |
Films (3, 4) and drum (6) carrying welding forms (10), pass an ultrasonic emitter (5), moving at differing speeds (V1, V2). This bonds the films along a welding zone differing in shape from that of the welding forms. Preferred features: The first assembly (comprising both films, 3, 4), is moved along at constant speed. The speed (V2) of the second assembly (comprising the welding drum and forms, 6, 10) is varied. V1 = Vn initially, a nominal speed. V2 is increased to an accelerated speed Va, then decreased back to nominal (Vn) to obtain a welding zone reduced in extent, i.e. foreshortened, in comparison with the size of the welding form (10). Between acceleration and deceleration, the drum runs at constant speed or is stopped. At least one acceleration or deceleration of the drum is instantaneous. The welding zone includes a straight line portion parallel to film motion. The speed V2 is varied. Either or both films are printed with a series of impressions. The process assures suitable matching between positions of printing and those of welding. If necessary, the films are re-positioned with respect to the matrix. |
