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bottle circumference
Fit checks
Key dimensions
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wrap label length
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sleeve lay-flat width
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overall verdict
Assumptions in this check
Methodology — the five checks
The checks run as a pipeline in the order a labeling engineer applies them. Every formula is shown with the constants used; limits of the standard U-Packer round-bottle OPP series come from themachine specification table.
1 — Wrap-around label length
L = π × (D + label film thickness) + overlap film thickness ≈ 0.03–0.06 mm (OPP) — negligible; overlap 10–15 mm, 12 mm used hereThe label must wrap the full circumference plus an overlap seam where hot melt bonds the trailing edge over the leading edge. L must stay within the machine's maximum tag length (600 mm on the standard series).
2 — Label height clearance
label height h ≤ usable body height − 2 × clearance (2–3 mm each side) and h ≤ machine maximum tag width (130 mm on the standard series)3 — Taper (conicity) check
taper angle θ = arctan((D_bottom − D_top) ÷ (2 × label height)) θ ≤ 1° → flat wrap OK · 1–2.5° → arc-shaped label · > 2.5° → use sleeve or two-panel self-adhesiveOn a conical bottle a straight label tries to follow a slanted surface and skews. The arc-shaped label is cut as a section of an annulus whose outer radius is approximated as R ≈ label height × D_bottom ÷ (D_bottom − D_top). The checker computes R when taper is detected.
4 — Small-diameter / high-speed handling
Below ≈ 40 mm body diameter, containers are tippy and the wrap-station contact arc is short; rotary machines need pucks or a timing-screw infeed. Not a disqualifier — an engineering flag for the quote.
5 — Shrink sleeve fit
lay-flat width W = π × D ÷ 2 × (1 + 5–8% pre-shrink margin, 6% used here) required shrink r = (D_applied − D_grip) ÷ D_applied material max TD shrink: PVC 52% · OPS 68% · PETG 75% (midpoints of the published ranges)Pass when r ≤ 80% of the material limit (production-safe), warning up to the limit, fail beyond it — a sleeve that cannot shrink to the smallest covered diameter will tent, bridge or wrinkle.
These checks cover geometry and process fit. Adhesion on treated/untreated surfaces, condensation, and container wall rigidity are verified with physical samples. Sizing a line as well? Use theCapacity Calculator; running costs are in theGlue Cost Calculator.
Frequently asked questions
How long should a wrap-around label be for my bottle?
Label length = π × (bottle diameter + label thickness) + overlap. Label film thickness is usually negligible (0.03–0.06 mm for OPP); the overlap is 10–15 mm and is where the hot melt seam bonds the trailing edge over the leading edge. A 65 mm bottle with a 12 mm overlap needs a ≈ 216 mm label.
My bottle is slightly conical — can I still use wrap-around hot melt?
It depends on the taper angle θ = arctan((D_bottom − D_top) ÷ (2 × label height)). Up to about 1° a flat label applies cleanly. Between 1° and 2.5° you need an arc-shaped (curved) label cut as a section of an annulus, which this checker dimensions for you. Beyond ~2.5° a flat or curved wrap will skew or wrinkle — use a shrink sleeve or a two-panel self-adhesive label instead.
What shrink rate do I need for a sleeve label?
Required shrink rate r = (application diameter − smallest diameter the sleeve must grip) ÷ application diameter. The sleeve is applied over the largest body diameter and must shrink down to the narrowest point it covers. Material limits: PVC ≈ 50–55% TD, OPS ≈ 60–75%, PETG ≈ 70–80%. Stay under 80% of the material limit in production to avoid tearing and distortion.
Is there a minimum bottle diameter for high-speed roll-fed labeling?
Below roughly 40 mm body diameter, bottles become tippy on the conveyor and the wrap station has very little contact arc — high-speed rotary machines need pucks or a timing-screw feed to keep them stable. Flag the diameter when you request a quote so the infeed is engineered for it.
Which labeling process should I choose for a shaped bottle?
Cylindrical or near-cylindrical bottles at speed: roll-fed hot melt wrap-around (lowest material cost). Flat or elliptical panels, premium look, moderate speed: self-adhesive. Full-body decoration, tamper band, or heavy taper/contours: shrink sleeve. The checker above flags the boundary cases with the reasons.