Roll Length and Splices: What You Should Actually Accept
A roll sold as 500 metres measures 480, and two extra splices show up mid-run. Both can be checked at goods-in with simple steps.
Two things cause most disputes at goods-in for roll labels: the length and the splices. A roll sold as 500 metres seems to run out early, and a roll that turns out to hold two splices makes the printer alarm twice. Both have objective answers and both can be checked on site.
Length is measured, not weighed
During slitting and rewinding, length comes from a measuring roller. That roller is driven by friction, so if the web slips on its surface or tension is too low and the web floats, the counter over-reads. Excessive tension causes the opposite error: the web stretches, the real length falls slightly short, and a metre or two accumulates over a full roll.
Deriving length from weight is worse. Dividing gross weight by grammage assumes stable moisture content, coating weight and liner weight. In production, adhesive coat weight varies and moisture content moves with the season, so a calculated length commonly lands 2 to 5 percent off. On a 500 metre roll, 2 percent is 10 metres.
How many splices are normal
Parent rolls generate splices at web breaks, at material changes and where defects are cut out. Common practice allows one or two splices per finished roll, with anything beyond that declared in advance. The splice itself is not a defect. The real issue is whether it is marked, and whether the marking is visible.
A splice roughly doubles the caliper at that point, which is where a thermal printer's gap sensor misreads and reports a missing gap or an out-of-paper condition. Manual application just means peeling the splice off and applying the next label. An automatic line usually has to stop. Marking the splice clearly, with a coloured tape flag or a folded corner, is what keeps the line running.
Winding tightness is the invisible spec
A roll wound too loose shifts in transit, then tracks badly on the machine and frays where the edge meets a guide. A roll wound too tight squeezes the adhesive, and after a few weeks in storage the adhesive squeezes out at the roll face, worst in summer. The hand test is to stand the roll upright and push it gently: it should roll without feeling slack. Pressing the face should give even rebound with no soft spot.
Face alignment deserves a look as well. A dull slitting knife or uneven tension produces steps, burrs or one edge protruding, and that roll will misbehave on any high speed line.
Three checks you can run at goods-in
First, pull three rolls and measure. On a flat floor, unwind ten metres, measure and mark it, and use the ratio to estimate the whole roll. More than 1 percent short is worth questioning. Second, count splices. Unwinding a full roll is impractical, so either watch for them during printing or require the supplier to flag each one and state the count. Third, inspect the roll face and the feel, which tells you about tightness and slit quality.
Put length tolerance and splice limits into the purchase contract and the argument disappears. State a minus tolerance of no more than 1 percent on nominal length, no more than two splices per roll, and every splice flagged. Acceptance then has a basis instead of an opinion.
Length deserves the tightest wording of all, because it is the easiest number to leave vague and impossible to reconstruct afterwards.
Keep the measuring roller clean as well. Adhesive dust builds on the surface, the web starts slipping, and the counter silently overstates length on every roll that follows.
