| 摘要 |
A flattened plastics foil ribbon (3), which is drawn from a blown foil extrusion unit at a prescribed constant drawing speed and is wound into a coil (4), is subjected before winding to a periodic angular displacement of a thickness error (10), which is effected by a displacement tool e.g. the extruder die (1), which rotates at a certain angular displacement velocity (w). To produce a coil 4 of truly cylindrical external form, the angular displacement velocity (w) is reduced as the plastics foil ribbon is wound, in proportion to the increase in the winding times for successive foil layers, thereby maintaining a constant displacement arc of the thickness error (10) for each of a long succession of foil layers. Equipment for carrying out this process incorporates a monitor (15) which emits a control signal based on the number of foil layers and/or the coil thickness, the rest of the control equipment being adapted so that the controller (14) for the displacement tool driving means (13) maintains a constant displacement arc. <IMAGE> |
