Coding trays and lidding film
Tray packs can be coded on the lidding web, the tray, a label or an outer sleeve. The best position depends on line movement, seal geometry, surface condition, artwork and how the finished pack is handled and inspected.
Choose the coding surface from the finished-pack requirement
The code must remain visible and readable after sealing, cooling, labelling, sleeving, weighing, metal detection, case packing and distribution handling as applicable.
| Code location | Advantages | Checks before selection |
|---|---|---|
| Lidding film web | A controlled flat surface before the pack is sealed; strong fit for TTO where the film and machine movement are compatible. | Web direction, intermittent or continuous motion, print window, registration, seal map, ribbon, mounting and finished-pack distortion. |
| Tray body | Can remain visible if the lid artwork changes or if the tray is the controlled traceability surface. | Tray material, curvature, moulding features, product temperature, moisture, print distance and product presentation. |
| Applied label or sleeve | Provides a defined printable area and can combine branding, legal or logistics information with variable coding. | Label stock, coating, application position, overprint timing, adhesive, condensation and label presence. |
| Outer carton or case | Useful for secondary identification and supply-chain data. | Relationship to the primary-pack code, product aggregation, carton surface, barcode specification and line tracking. |
Control the lidding-film print window
Registration and position
Map the finished tray code position onto the flat web. Use registration marks, machine index and printer delay or encoder information as required by the host machine.
Seal and cut geometry
Keep the mark clear of seal bands, peel tabs, perforations, cuts and areas stretched by the tray profile. Confirm that the code does not interfere with seal inspection.
Access and ribbon change
Allow safe access to the printhead and cassette without compromising guarding, film threading or hygiene. Include access in the approved layout.
Test the finished tray, not only a flat film sample
Sealing heat, tension, condensation and handling can change a code after it leaves the printer.
- Print the complete worst-case date, batch and machine-readable message on production film.
- Run the web through the actual or representative sealing cycle at agreed conditions.
- Inspect code position relative to the tray, seal, label and artwork.
- Allow the pack to cool or equilibrate as it would in production.
- Check abrasion from belts, guides, stacking, sleeves and case packing.
- Scan or verify barcodes and 2D codes on the finished pack where required.
Temperature and moisture are application variables
Cold product, steam, condensation, frozen surfaces and washdown can affect direct inkjet marking. If the controlled lidding web is coded before these conditions occur, TTO may provide a more stable route; the actual film and process still need testing.
Use the print-quality testing guide to record adhesion, rub, contrast and scanning on the completed tray pack.
Integration questions for tray lines
Host machine
Make, model, lane count, web width, motion, cycle, registration and available mounting interface.
Message control
Product job, date rule, batch source, lane-specific data and authorised change procedure.
Inspection
Whether the camera sees flat web or finished tray, the defect to detect, product tracking and response.
Changeover
Tray dimensions, reel and artwork changes, print-position adjustment, recipe selection and first-off approval.
Prepare a tray coding enquiry
Send lidding film and tray samples, including the production artwork and any colour or material variants. Mark the preferred code area and areas that must remain clear.
Provide a line video or drawing showing the web path, tray index, coder position, sealing station and downstream contact. Include normal and maximum production movement.
Supply the complete message, date and batch rules, barcode or 2D data and the method used to select or transfer the correct job.
State whether the code must be inspected before or after sealing and the required response to a failed or missing mark. Include lane tracking if the machine has more than one product lane.
Tray and lidding-film coding FAQs
Where should a date code be printed on a sealed tray?
Possible positions include the lidding film, tray body, applied label or outer sleeve. Choose an area that remains visible, stable and undamaged after sealing, cooling, handling and retail presentation.
Is TTO suitable for lidding film?
TTO is often assessed for high-quality variable printing on compatible flexible webs. Suitability depends on film surface, web movement, print window, ribbon and the tray-sealing machine interface.
How does condensation affect tray coding?
Moisture can affect ink adhesion, contrast and inspection. Test the actual product and temperature transition, and consider printing on the controlled web before condensation occurs where the process allows.
Can the code be printed inside the seal area?
The print position should not compromise the seal or be hidden or distorted by it. Confirm the approved area with the packaging and sealing process owners and test finished packs.
What samples are required?
Provide production lidding film, trays, labels or sleeves, complete artwork, filled or representative packs and details of sealing temperature, line movement and downstream handling relevant to the code.
Map the flat-web print to the finished tray
Send the tray, lidding film, full message and sealing-machine details for a coding application review.