Direct answer
Define label position from stable pack datums, include allowable skew and wrap overlap, stabilise the container, and inspect the features that determine customer acceptance. Prove the method across container, label and application variation rather than using one perfect sample.
Create a dimensional label standard
Specify top, bottom and side-edge position, skew, wrap overlap or gap, front-to-back relationship and orientation to a mould seam, handle or closure. Use drawings or controlled samples with clear datums.
A wide tolerance described only as “looks straight” is difficult to validate and can create operator disagreement.
Account for container geometry
Taper, ovality, seams, embossing and transparent walls affect both application and inspection. The vision system needs a reliable reference that remains visible throughout normal container variation.
If the container can rotate after labelling, inspect immediately or add orientation control.
Inspect identity as well as position
Where risk requires it, verify artwork, colour, barcode, date-code area or product name in addition to label presence. Use the production recipe to define the expected result.
Control recipe selection and user access so the camera does not approve the wrong label against the wrong expected artwork.
Use defect data to correct the process
Trend skew, vertical drift, missed labels and web breaks by reel, operator, speed and machine setting. This helps identify sensor drift, web tension, wipe pressure or container-control problems.
Set escalation rules for repeated defects rather than allowing the reject bin to become the only control.
Information to prepare
- Approved label-position drawing or samples
- Container reference datum
- Skew, wrap and front/back tolerances
- Artwork and identity checks
- Lighting and product-control method
- Reject tracking and confirmation
- Defect trending and escalation rules
Labelling Machines UK
Labelling-machine routes for controlled placement on bottles, jars and other packs.