NO MORE BURN MARKS IN PE FILM EXTRUSION

Maintenance extended from 2 weeks to 8 months.

Client Context
A leading international manufacturer of polyethylene (PE) films for automatic packaging systems (VFFS and HFFS), serving both the food and agricultural sectors.

The company operates high-performance co-extrusion lines supplied by a globally recognized OEM in film extrusion technology.

Production volumes were high. Quality standards were uncompromising.
However, restart stability had become a critical issue.

The Technical Challenge
At every restart, burn marks appeared on the PE film surface.

These defects were caused by localized polymer degradation inside the plasticizing unit, a common phenomenon in PE extrusion when material overheats and carbonizes in critical areas.

The consequences were significant:

• Visible defects on the film
• Frequent screw extraction and manual cleaning
• Maintenance required every 1–2 weeks
• Production downtime and increased operating costsThe issue was not related to the extrusion line itself, but to material adhesion and thermal stress within the screw mixing sections.

Euroviti’s Engineering Approach
After a technical evaluation of the process conditions and material behavior, Euroviti supplied:

• 2 screws Ø65 mm
• 1 screw Ø90 mm

for the co-extrusion line.

The mixing sections were treated with EUVTIN (TiN PVD coating), featuring a surface hardness of 2000–2500 HV.

This advanced coating technology was selected to:

• Reduce friction coefficient
• Increase resistance to abrasion and corrosion
• Minimize polymer adhesion on steel surfaces
• Improve melt flow stability during shutdown and restart phases

By lowering surface interaction and preventing material stagnation, the risk of carbonization was effectively eliminated.

Measurable Results
The impact was immediate and measurable:

✔ Complete elimination of burn marks at restart
✔ Stable and consistent film quality
✔ Screw cleaning interval extended from every 2 weeks to once every 8 months