Introduction and purpose
Thermoforming Design Twin is a technical support tool for calculating and documenting material reduction scenarios for thermoformable multilayer packaging.
The tool follows the source-reduction approach of UNE-EN 13428:2005: reducing packaging weight or volume to the minimum adequate level while maintaining functionality, product and user safety and hygiene, and packaging acceptability.
It can also support the preparation of the packaging minimisation assessment required by Regulation (EU) 2025/40 on packaging and packaging waste —PPWR—. From 1 January 2030, packaging weight and volume must be reduced to the minimum necessary to ensure functionality, taking into account the performance criteria and methodology set out in Annex IV.
What does it calculate?
Based on cavity geometry, film structure and selected process conditions, the model estimates global and local draw ratios, residual total and layer thicknesses, barrier performance and technical risks. It then identifies an estimated technical minimum, a recommended minimum including a safety margin, the potential downgauging percentage and the limiting criterion.
Intended use and limitation
This is an uncalibrated Class C model intended for technical screening, comparison of alternatives, test prioritisation and generation of design evidence. It does not by itself certify compliance with UNE-EN 13428 or the PPWR and does not replace industrial validation, food-contact assessment, barrier testing, sealing validation or supply-chain performance verification.
1. Cavity geometry
Process and application
2. Film structure
Layers
| Material | Function | Thickness µm | Minimum µm | Locked |
|---|---|---|---|---|
The sum of the layers automatically defines the current total thickness.
3. Results
Critical zone and residual thicknesses
| Zone | Local draw ratio | Total thickness | Minimum EVOH | Minimum PA | Minimum PE |
|---|
Diagnosis
User instructions
The user may modify the fields listed below to represent a specific tray, forming process and multilayer film. After changing the inputs, select Calculate and optimise to update the results.
Cavity geometry
Enter the top and bottom dimensions, depth and radii of the formed cavity. The bottom dimensions must not exceed the top dimensions. Smaller radii and greater depth generally increase local draw severity.
Process and application
Select whether plug assist is used, enter the forming temperature and define the puncture-risk and humidity exposure levels. The target OTR represents the maximum acceptable oxygen transmission rate for the intended application.
Film structure
Each row represents one layer. The user may change the material name, function, current thickness, minimum flat thickness and locked status. Locked layers are not reduced during selective optimisation.
Reduction strategy
Selective reduction decreases only unlocked layers until their defined minima are reached. Proportional reduction decreases all layers by the same factor. The optimisation step controls the thickness interval evaluated, and the safety margin is applied above the estimated technical minimum.
Interpreting the results
The recommended minimum is the calculated technical minimum plus the selected safety margin. The coloured indicators show the estimated status of barrier, formability, mechanical resistance, residual PA, sealing, pinholes and OTR compliance. Internal penalty factors are calculated continuously, while the colours remain decision categories. Red means that the candidate is rejected by the current screening criteria.
Important limitation
Material identifiers, minimum layer thicknesses, OTR values, puncture-risk level and safety margin must be entered using technically justified values. The tool does not validate material grades, legal compliance, food-contact suitability or actual forming performance. All reductions must be confirmed by industrial trials and the relevant packaging performance tests.