January 30, 2026
Flexible packaging delivers exceptional performance, but its complex, multi-layer structure and high-speed production environment can lead to specific challenges. Understanding these issues and their root causes is key to ensuring quality, efficiency, and customer satisfaction. Here is a guide to the most frequent problems and their proven solutions.
These issues directly compromise the package's primary function: to protect and contain the product.
| Problem | Description & Impact | Root Causes | Solutions |
|---|---|---|---|
| Weak Seals / Leakers | Seals have low strength or contain channels, leading to leaks and contamination. | • Incorrect temperature/pressure/dwell time settings. • Contamination on sealing surfaces (product dust, oil, moisture). • Wrong sealant material for the application. • Worn or dirty sealing jaws. |
• Optimize sealing parameters via validation testing (T-test, burst test). • Implement effective cleaning protocols for sealing areas. • Use ionomer sealants (e.g., Surlyn®) for sealing through contamination. • Ensure proper jaw alignment and maintenance. |
| Burn-Through / Charring | Seal area is overly melted, discolored, or brittle, creating a weak point. | • Excessive sealing temperature. • Excessive dwell time. • Poor heat distribution across jaws. |
• Reduce temperature and/or dwell time incrementally. • Use thermocouples to map and ensure even jaw temperature. • Consider a sealant with a broader heat-seal range. |
| Wrinkles in Seal Area | Wrinkled films within the seal, creating potential leak paths. | • Excessive film tension during the forming/filling process. • Film misregistration on vertical form-fill-seal (VFFS) machines. • Poor film formulation (excessive shrink). |
• Adjust film web tension controls. • Check and correct guide rollers and registration systems. • Work with supplier to adjust film's shrink characteristics. |
Issues related to the film's physical properties or the laminate's construction.
| Problem | Description & Impact | Root Causes | Solutions |
|---|---|---|---|
| Delamination | Layers of the laminate separate, destroying barrier properties and aesthetics. | • Insufficient adhesive/laminating bond strength. • Material incompatibility between layers. • Product chemistry attacking the adhesive (e.g., essential oils, acids). • Stress cracking from flexing or impact. |
• Review adhesive system and lamination process with converter. • Conduct compatibility testing with the actual product. • For aggressive products, use enhanced adhesive chemistries (e.g., polyurethane, acid-cured). • Increase film flex-crack resistance. |
| Pinholes & Flex Cracking | Microscopic holes develop, allowing gas/moisture transmission and reducing shelf life. | • Abrasion during manufacturing, filling, or shipping. • Excessive mechanical stress on brittle layers (e.g., metallization, EVOH). • Poor film quality or formulation. |
• Improve film handling to minimize contact with abrasive surfaces. • Add a protective over-lacquer on metallized films. • Re-engineer the structure to place brittle barrier layers (like EVOH) closer to the neutral axis of the laminate. • Use tougher nylon or PET layers for puncture resistance. |
| Poor Barrier Performance | Actual oxygen/moisture transmission rates are higher than specifications, shortening shelf life. | • Incorrect material selection for the product's needs. • Undetected pinholes or cracks in barrier layers. • High humidity degrading EVOH barrier. • Inadequate seal integrity (see above). |
• Conduct real-time shelf-life testing to validate material choice. • Perform destructive testing (dye penetration) for pinholes. • For moisture-sensitive products, encapsulate EVOH between high-moisture barrier layers (PP/PE). • Use foil or metallization for absolute/high-barrier needs. |
Defects that affect the package's appearance and brand image.
| Problem | Description & Impact | Root Causes | Solutions |
|---|---|---|---|
| Ink Adhesion / Rub-Off | Ink easily scratches or transfers off the film surface. | • Incorrect surface treatment level (dyne level) on the film. • Mismatched ink system for the substrate. • Insufficient ink curing/drying. • External plasticizers (from adhesive) migrating to the surface. |
• Measure and specify dyne level (should typically be >38 dynes/cm). • Perform ink adhesion tests (tape test, rub test) pre-production. • Optimize oven temperatures and press speeds for full curing. • Ensure adequate curing time for solvent-based or UV inks. |
| Registration & Banding Issues | Print colors are misaligned or show repetitive streaks/bands. | • Tension fluctuations in the web press. • Worn or damaged print cylinders/gears. • Viscosity variations in the ink. |
• Maintain consistent web tension throughout the press. • Implement preventive maintenance on cylinders and bearings. • Use closed-loop viscosity control systems in the ink fountains. |
| Odor / Taste Transfer | Unpleasant smell or taste migrates from the package to the product. | • Residual solvents from inks, adhesives, or coatings. • Low-quality recycled content with contaminants. • Oxidation of inks or films. |
• Enforce strict solvent retention specifications for suppliers. • Use low-odor, low-migration ink and adhesive systems. • Quality audit PCR materials for odors. • Conduct sensory testing on finished packages. |
Issues that arise during the packaging manufacturing or filling process.
| Problem | Description & Impact | Root Causes | Solutions |
|---|---|---|---|
| Poor Web Handling | Film jams, wrinkles, or breaks on the production line. | • Incorrect or uneven web tension. • Excessive static electricity. • Out-of-spec film stiffness or slip properties. • Misaligned rollers or guides. |
• Calibrate and synchronize tension zones (unwind, infeed, rewind). • Install static elimination bars at key contact points. • Specify and control coefficient of friction (COF) – both static and kinetic. • Ensure proper machine alignment. |
| Inconsistent Tear / Openability | Consumers struggle to open the package, or it tears unpredictably. | • Poorly designed tear notch (geometry, depth). • Film is too strong/tough in the tear initiation area. • Seal is stronger than the film surrounding the notch. |
• Redesign the tear notch (laser scoring often more precise than mechanical). • Use a dedicated easy-tear film layer (oriented direction is critical). • Balance seal strength with film tear strength through testing. |
The best solution is proactive prevention. Implement this framework:
Design for Manufacturability (DFM): Involve your packaging converter and filler early in the design process. Prototype and run machine trials.
Comprehensive Specifications: Develop detailed specs for materials (dyne level, COF, sealant melt point), printing (color standards, adhesion), and final package performance (seal strength, barrier).
Incoming Quality Control (IQC): Test incoming rolls for key properties (thickness, seal strength, barrier, print quality) before full production.
Process Validation: Document and validate all critical machine settings (temperatures, speeds, tensions) for each job. Use Statistical Process Control.
Root Cause Analysis: When a problem occurs, use methodologies like 5 Whys or Fishbone Diagrams to find the fundamental cause, not just treat the symptom.
Conclusion: Most flexible packaging failures stem from a mismatch between material properties, machine settings, and product requirements. Success is achieved through collaborative partnerships between brand owner, packaging converter, and filler, underpinned by clear communication, rigorous testing, and controlled processes. Investing in preventive analysis and validation upfront saves significant cost and brand reputation compared to reacting to field failures.
