Leadtech Printer-Leading Manufacturer in the Coding & Marking Industry since 2011.
When Ink Beads Up: UV-Laser Coding for Plastic Packaging
Plastic Packaging Coding & Marking
Substrates: PET · HDPE · LDPE · PP · PVC · ABS | Formats: Bottles · Caps · Tubes · Pails · Trays
√ Rechnology: Continuous Inkjet (CIJ) · UV Laser · CO₂ Laser
√ Recommended LT Model: LT900 · LT800 Pro / LT810 Pro · UV Series (5 W / 10 W)
√ The One Constraint: HDPE and LDPE have low surface energy — dye ink beads instead of wetting, so codes smear on contact or wipe off in handling. Use a specialized ink, UV Laser (white HDPE), or fiber laser.
Plastic packaging spans beverage, personal care, food, household, pharmaceutical, and industrial goods — bottles, buckets, cups, trays, caps, tubes, and cans. Coding is driven by date and batch compliance plus product traceability. One quantifiable fact: PET bottles and HDPE containers are among the two most-coded substrates in consumer-goods manufacturing. Recyclability is now an explicit requirement — inks must be low-migration, non-bleeding, and separable so they do not degrade recyclate.
| Substrate | Key Property | Coding Implication |
| PET | Transparent, smooth, lightweight | CIJ or CO₂/UV laser; condensation is the real constraint on beverage lines |
| HDPE | Low surface energy | Hardest common rigid-container plastic for ink; UV laser advantaged on white HDPE |
| LDPE | Lowest surface energy among common plastics | Ink adhesion is the primary failure mode; specialized ink or laser required |
| PP | Compatible with most technologies | Choice depends on color, additives, and formulation |
| PVC | Compatible with most technologies | Laser response varies by formulation |
| ABS | Industrial parts more than packaging | Laser and TIJ preferred for permanent high-resolution marks |
Coding Challenges
- Low surface energy (HDPE/LDPE/PP) → ink beads instead of wetting → codes smear on contact or wipe off in handling. Specialized ink or a laser alternative is required.
- A chilled bottle leaves the filler → a condensation film forms → dye ink beads and the code fails to read. Use a penetrating CIJ ink, or laser, which surface moisture does not affect.
- A curved container surface (bottle/tube) → printhead standoff varies with the curve → inconsistent placement and legibility. 360° printing direction and a stable throw distance are required.
- Ink migration/bleed on food-contact and recyclable packaging → contaminates recyclate and conflicts with food-contact goals → recycled material quality degrades. Low-migration, non-bleeding, separable ink — or ink-free laser — is required.
| Technology | Fit | Why / Why Not |
| Continuous Inkjet (CIJ) | ★ Recommended | Universal high-speed workhorse across PET, PP, PVC, coated plastic; handles variable data and curved surfaces at line speed |
| UV Laser | ★ Recommended | Permanent, ink-free, high-contrast on white HDPE and mono-material recyclable film; cold marking, minimal thermal impact |
| CO₂ Laser | ○ Alternative | Permanent no-consumable mark on PET; choose when permanence outranks variable-data flexibility |
| Fiber Laser | - Not recommended | 1064 nm wavelength is poorly absorbed by transparent PET — a weak mark or none at all |
| Piezoelectric Inkjet (PIJ) | - Not recommended | Piezo large-character inkjet is built for porous corrugated board, not small curved plastic containers |
Split by substrate fir ews st: clear PET → CIJ or CO₂/UV laser; white HDPE and recyclable film → UV laser; low-energy LDPE needs a specialized ink or a laser. Do not put fiber laser on transparent PET — the wavelength barely marks it.
Typical Code Content
Recommended LT Solution
FAQ
