Running a Packaging Line Trial: A Practical Guide for Blister and Strip Packaging

Material specifications and supplier data sheets describe performance in the laboratory. A packaging line trial shows how the same material behaves under the heating, forming, and sealing conditions of your own machine. For blister and strip packaging, a structured trial prevents most of the problems that otherwise appear during commercial production.

Why a Line Trial Is Necessary

Laboratory testing measures material properties. It does not capture the interaction between material and machine, which is where most forming and sealing problems originate. Common issues that only appear in production include:

• Forming temperature windows that are narrower than the material data sheet suggests
• Deep cavities that perforate at the corners despite compliant thickness
• Seal strength variation caused by heat transfer differences in the land area
• Print registration drift on pre-printed lidding foil

A trial with production-representative material and settings identifies these before a commercial batch is committed.

Preparation Before the Trial

A useful trial starts with a clear plan:

1. Define success criteria in advance. Cavity wall thickness, seal strength range, code readability grade, and a target reject rate. 2. Request production-representative samples. Trial material should come from a production lot, not a laboratory sample. 3. Prepare enough material. Trials generate waste while settings are optimized; undersupplying material forces an early stop. 4. Confirm tooling condition. Worn forming tools distort results, so verify tooling before the run. 5. Agree the measurement method. Decide how cavity wall thickness and seal strength will be measured and by whom.

Parameters to Record

Record the full parameter set, not just the final settings. The path to the final settings is what tells you how much margin the material provides.

Where possible, run the material across a range of forming temperatures rather than at a single point. The width of the acceptable range is the practical measure of process robustness.

Evaluating the Results

After the trial, assess:

• Forming quality — cavity wall thickness distribution, absence of perforation, dimensional consistency
• Seal quality — strength within the agreed range, clean peel behavior, no channel defects
• Code quality — readability grade on the actual printing setup
• Reject rate — compared against the target set before the trial
• Process margin — how far settings can drift before quality degrades

A material that meets the specification but only within a very narrow parameter window is a production risk, even if the trial itself passes.

After a Successful Trial

Document the approved parameters, retain samples of the trial material and a reference batch of produced packs, and confirm that the material lot used in the trial matches the specification that will be ordered. Any change to material formulation, thickness tolerance, or tooling invalidates the trial result and requires requalification.

Our technical team can provide production-representative samples and support the parameter planning for a line trial — see the products page for the relevant material ranges, or contact us to arrange a trial.