How should bottle label placement tolerance be specified and checked?

What should a placement-tolerance statement contain?

State the label or artwork feature being measured, its target position, the allowed movement in each relevant direction and the conditions of the test. Identify the bottle format, label roll, fill state, running condition and whether the value applies after initial setup, during stable running or after a changeover.

Use a drawing or marked approved bottle rather than a sentence alone. The acceptance sheet should also state who measures, which tool is used and how results are recorded.

Where should label position be measured from?

Measure from a physical bottle feature that is repeatable and relevant to presentation, such as the base, a panel edge or another controlled datum. For rotational placement, identify the seam, handle, cap feature or panel centre used as zero. If the chosen bottle feature itself varies, that variation must be recognised in the acceptance method.

Do not measure from an unstable visual reference such as a distorted reflection or a mould detail that changes between cavities unless its variation has been assessed.

How many formats and samples should be included?

Include every format that has its own acceptance requirement and the formats that create the greatest handling challenge. The number of measured samples should be sufficient to show normal variation and should be agreed for the project; one approved bottle demonstrates appearance, not repeatability.

Where a machine is expected to change between formats, repeat the check after the agreed changeover sequence. Keep individual results rather than only a pass statement.

How should front-to-back registration be defined?

Define each label from a common bottle datum and separately define their relationship to one another. This may include vertical alignment, centre-line relationship, spacing around a round bottle or alignment of specific artwork features. Front-to-back registration should not be assumed from two independent label-position statements.

Use both production rolls during the trial because different label sizes, liners or release behaviour can alter each head independently.

How should cosmetic appearance and measurable tolerance be separated?

Placement measurement shows where the label sits; it does not by itself assess wrinkles, bubbles, edge lifting, trapped contamination or artwork appearance. Record cosmetic requirements as separate acceptance points with approved examples or clear defect descriptions. This prevents a visually unacceptable pack passing only because its measured position is correct.

What evidence should be retained at FAT and commissioning?

Keep the approved drawing or sample, bottle and label-roll identities, individual measurements, photographs, machine setup references and any agreed exceptions. Site commissioning should use the same method so results are comparable. If the materials or format have changed, record that change rather than treating the two tests as equivalent.

The FAT checklist and commissioning checklist show how to carry evidence through the project.