Application guide
What can a can-inspection system check?
Machine vision can inspect beverage, food and suitable aerosol cans for visible packaging and presentation defects. Top, side and base views can be combined to cover the lid or end, cylindrical body, printed decoration, applied labels and traceability codes.
The achievable checks depend on whether the cans are empty or filled, their surface finish, line speed, rotation and the smallest relevant defect. Highly reflective metal needs controlled diffuse lighting so normal highlights are not mistaken for dents or contamination.
Visible can defects and identity checks
- Gross dents, deformation and visible sidewall damage
- Lid or end presence and selected visible assembly features
- Pull-tab presence, position and gross damage
- Rim and top-surface presentation where the camera has a clear view
- Printed decoration, applied label and approved variant identity
- Date, batch, barcode and 2D-code presence or content
- Visible fill indication where the pack and product permit optical inspection
- Multipack, tray, case and pallet checks downstream
What vision inspection does not prove on its own
A camera assesses visible features. It does not by itself prove pressure, leak tightness, microscopic double-seam integrity or internal product condition. Where these are critical, vision should be combined with the appropriate seam, pressure, leak, X-ray, weight or process-control method.
The project specification should separate cosmetic acceptance from functional integrity and define which equipment owns each decision. This avoids expecting a surface image to validate a condition that cannot be seen.
Control reflections and full-circumference coverage
Bright-field, dark-field, dome and polarised lighting can reveal different surface conditions. A single side camera only sees part of a cylindrical can, so broad circumference coverage may require multiple cameras, controlled rotation or specialised 360-degree optics. The best choice depends on line speed, footprint and required defect resolution.
Inspection before and after filling
Empty-can inspection can target incoming body and end defects before product is added. Post-fill inspection can add closure, code, label and pack-presentation checks. Positioning each camera where the relevant feature is exposed normally produces a more reliable result than trying to inspect every condition at one point.
Automatic rejection at can-line speed
Close product pitch and high speed make timing, tracking and reject-device recovery important. Encoder tracking, a suitable reject mechanism, confirmation sensing and secure containment can be designed around the conveyor and can stability. Consecutive failures or a reject fault can trigger a controlled stop.
Build the complete can-line inspection
Connect can inspection with fill-level checks, date-code verification, beverage inspection and end-of-line case and pallet control.