How to specify a label inspection system

1. Which faults must the system find?

List each defect in observable terms: missing label, label more than an agreed distance too high, wrong artwork variant, unreadable date code, or a missing regulatory symbol. Avoid vague requirements such as “check the label is good”.

2. What product variation is normal?

Provide the full pack and label range, including approved print, material, colour and placement variation. A system must accept legitimate production variation while rejecting meaningful faults.

3. Which label surfaces must be inspected?

Front, back, neck and wraparound labels may require separate views. Curved packs hide surfaces from a single camera, while reflective containers can require specialised lighting geometry.

4. What are the real line conditions?

Specify current and expected maximum speed, product pitch, stops and starts, conveyor vibration, environmental cleaning and available space. Include the least favourable normal conditions, not only the nominal running point.

5. How will products be presented?

Reliable inspection depends on controlled orientation, spacing and distance to the camera. Guides, timing screws, belts or other handling may be needed before image processing can be repeatable.

6. What image resolution is required?

The smallest critical feature or defect must occupy enough pixels to be assessed. This determines field of view, camera resolution, lens selection and the number of cameras.

7. How are recipes selected?

Define who can create, edit and select recipes, and how the system confirms that the correct reference is active. Recipe control is fundamental to wrong-label prevention.

8. What should happen on a fail?

Choose automatic reject, line stop or operator alarm based on product behaviour and risk. Define how the failed product is tracked between inspection and removal.

9. How will rejection be confirmed?

For higher assurance, add sensors that confirm a failed pack entered the reject route. Consider reject-bin capacity, locking, air pressure and what should happen if any safeguard fails.

10. What data should be recorded?

Agree counts, failure reasons, images, timestamps, recipes and retention periods. Store only what the process will use, and define who needs access.

11. How will changeovers be challenged?

Plan known-good and known-bad samples for each critical recipe. Operator procedures should confirm the system and reject device work after changeover or intervention.

12. What proves the system is accepted?

Create an agreed test set, line conditions and acceptance criteria before manufacture. This provides an objective basis for factory and site acceptance testing.

What affects label inspection system cost?

The main cost drivers are the number of label views, camera resolution, line speed, product handling, enclosure standard, reject hardware, controls integration, recipe and data requirements, documentation, validation support, installation and commissioning. A simple single-view label-presence check is fundamentally different from a multi-camera 360° system with OCR, data comparison and fail-safe rejection. Our label inspection cost guide explains how to prepare a useful budget enquiry without publishing a misleading one-size-fits-all price.