Flying splices on turret unwinds and other unwinds generally produce a butt splice. The splice may be biased or even have a complex taping pattern. The splice is made very quickly at running speed with a paste brush or paste roller followed inches or centimeters later by a knife cut.
Due to spacing differences between where the paste and cut take place, an overlap or tail results from a flying splice. This is a region where two layers of web overlap, held together with double-sided tape. The tail may be wrinkled or have a ragged edge.
A shorter tail runs through the remainder of the web line better than a long tail. Tail length is a setting on the splice controller. How well does the tail length setting on your controller match the actual tails seen at your winder?
The first step is recovering the splice at the winder. Most winders coordinate the winder to index just at the point of splicing. The splice then ends up buried at the core, or at the outside of the completed roll.
It may make economic sense to bury the splice, particularly if the web at the core is deemed unusable and the tail near the core does not crate defects in the roll. Burying the splice moves the problem of disposing of the splice to the downstream consumer of the roll.
Indexing with the spice on the outermost wrap of the completed roll permits inspecting and disposing of the splice immediately after each splice.
The faster the line, the more difficult to get a short tail. In the paper industry, flying splices are consistently made at speed in excess of 2,000 mpm.
To get a consistent short tail, the timing of the paster and knife must be very repeatable. The glue line marker must be set very accurately by the operator. The splice controller must be very fast (<1 msec). Fast sensors (minimal filtering) for the detection of the glue line should be used. Sensors and actuators should be wired directly to the splice controller and not through a PLC or other device. Consider whether the diameter of the incoming roll affects the timing of the splice. Diameter changes may affect the splicer and knife stroke thus changing the timing. Finally, it is important to calibrate the timing of the splicer and knife. Your splice controller vendor should have provided a procedure and sensors for this calibration.