Label Layout on the Cylinder
How many labels fit around the cylinder and across the web, the real gap between them and how much material goes to waste.
- filled: labels
- hatching: waste (margins, gaps, what is left over)
- dashed: the limits of one turn of the cylinder
How it is calculated
Around: N = the whole part of P ÷ (L + g). The real gap = P ÷ N − L: the repeat is shared out evenly between the labels.
Across: n = the whole part of (W − 2m + g2) ÷ (w + g2); what is left = (W − 2m) − (n × w + (n − 1) × g2).
Waste = 1 − (n × w × N × L) ÷ (W × P): the share of the web area not taken by labels.
N = floor(P / (L + g)) gap = P / N − L n = floor((W − 2m + g2) / (w + g2)) waste = 1 − n·w·N·L / (W·P)
Worked example
P = 292.1 mm, L = 70 mm, g = 3 mm: N = floor(292.1 ÷ 73) = 4; gap = 292.1 ÷ 4 − 70 = 3.025 mm.
W = 330 mm, m = 5 mm, w = 100 mm, g2 = 3 mm: n = floor(323 ÷ 103) = 3; left over = 320 − (300 + 6) = 14 mm; waste = 1 − (3 × 100 × 4 × 70) ÷ (330 × 292.1) = 12.86%.
An estimate: purely geometric, without plate stretch allowances or the press's technical strips.
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