Printing and Variable Data on Lidding Foil: Practical Considerations

Lidding foil carries more information per square centimetre than almost any other piece of pharmaceutical packaging. Product name, strength, batch number, expiry date, and increasingly serialization data all appear on the seal. Getting the printing right is a joint responsibility between the converter and the packer.

Base Printing Versus Variable Data

It helps to separate two layers of printing:

• Base print — the product name, strength, and branding, printed during foil manufacturing by rotogravure. This is fixed and part of the released specification.
• Variable data — batch number, expiry date, and serialization codes, applied during packing on the customer's line.

The material supplier controls the base print. The packer controls the variable data. Most problems occur at the interface between the two.

Print Methods for Variable Data

The choice depends on line speed, data density, and the required readability standard.

Readability and Verification

Serialization data usually requires machine-readable codes with defined quality grades. Practical points:

• Contrast matters more than print resolution. Code readability depends on the contrast between the code and the background.
• Lacquer compatibility affects ink adhesion. A lacquer that works well with one print method may perform poorly with another.
• Verification must happen on the line. Grade a sample from your own production run, not from a supplier-provided sample.
• Storage conditions affect codes. Verify readability after the product has been stored at elevated temperature and humidity, particularly for markets in hot-humid zones.

Practical Checklist

Before finalizing a lidding specification for a coded product:

1. Confirm the print area available for variable data, and its position relative to the cavity 2. Confirm which lacquer system your print method requires 3. Run a line trial and grade the codes produced 4. Re-verify after accelerated storage 5. Agree the acceptance criteria with your quality team in advance

Our PTP aluminum foil range is available with lacquer systems suited to common variable data print methods. For technical guidance on print area and lacquer selection for your line, contact us.