Application guide
Where should blister inspection take place?
The best inspection point depends on the defect. Before sealing, a camera has a clear view of each cavity and its contents. After lidding or foil application, the system can inspect visible pack formation, printed information, codes and selected seal-area conditions. A complete concept may therefore use more than one station.
Oxford Vision Systems develops the camera, light, triggering, recipe and failed-pack response around the blister machine or downstream conveyor. Final performance is established with representative products and the customer's approved quality criteria.
Blister defects and checks that may be targeted
- Missing, extra, misplaced or grossly damaged tablets, capsules or components
- Wrong colour, shape or approved product variant
- Empty cavities and selected visible contamination
- Cavity, web and cut-position alignment
- Backing foil or lidding material presence and gross presentation defects
- Printed batch, expiry, lot, barcode and Data Matrix information
- Visible seal-region folds, trapped material or incomplete presentation
- Blister-to-carton identity and count correlation downstream
Define what can and cannot be seen
Vision is a non-contact visual method. It can identify features exposed to the camera with sufficient contrast and resolution. It does not automatically prove microscopic seal integrity, sterility, chemical identity or an internal condition hidden by opaque foil. Separate process controls or test methods may be required.
Clear acceptance criteria should distinguish a visible cosmetic defect from a critical product or packaging failure. Borderline samples are particularly valuable when setting a realistic pass/fail boundary.
Product presentation, colour and reflection
Transparent webs, glossy pockets, metallic foils and products with similar colours can reduce contrast. Lighting geometry, polarisation, background design and camera angle are selected to isolate the target feature. Web movement and registration must also be stable enough for the required cavity-level resolution.
Recipe control, records and validation support
Multi-format lines need protected recipes for cavity layout, product appearance, print fields and decision tolerances. The controls can be designed with user permissions, batch references, fault records and selected image storage where required. The customer remains responsible for the overall validation strategy and approved acceptance criteria; Oxford Vision Systems can provide agreed test documentation and evidence for the supplied inspection scope.
Project information to provide
- Blister layouts, pocket dimensions and web direction
- Good, failed and borderline product examples
- Clear and opaque materials, foils and every approved colour variant
- Machine cycle rate, indexing behaviour and available trigger signals
- Required pre-seal, post-seal and downstream checks
- Reject or line-stop method and failed-web handling
- User, record, audit and documentation requirements
Related pharmaceutical packaging checks
Combine blister inspection with pharmaceutical packaging inspection, expiry and lot-code verification, Data Matrix inspection and carton control.