Technical Insight
Laser Marking PET: Transparent vs Opaque Formulations
Treat transparent and opaque PET as different optical systems: define the required mark polarity, crystallinity and colour package before choosing an additive or laser window.
Author: Aurexene Materials Engineering Team · Last updated: 2026-08-28
Quick Answer
Treat transparent and opaque PET as different optical systems: define the required mark polarity, crystallinity and colour package before choosing an additive or laser window.
Evidence scope: This page provides method-conditioned engineering guidance. It does not claim that one commercial grade is a drop-in replacement, universally superior, or qualified for a finished part without matched evidence.
Problem
Treat transparent and opaque PET as different optical systems: define the required mark polarity, crystallinity and colour package before choosing an additive or laser window.
The decision boundary includes the complete host formulation, colour package, supplied additive form, compounding and moulding history, part geometry, delivered laser state and the measurement method. A result is not transferable when one of those conditions changes without review.
Mechanism
PET morphology, thermal history, nucleation, fillers and pigments alter absorption, heat flow and whether marking produces colour change, foaming or damage.
Laser marking is a coupled material-and-process response. Absorption and scattering determine where energy is deposited; pulse state, focus, overlap and path determine the local history; the polymer, pigments, fillers and geometry determine whether that history creates controlled contrast or a defect.
Tradeoff
A condition that marks opaque PET quickly can haze, yellow or distort a transparent construction.
The useful condition is a feasible region with margin, not the single darkest coupon. Contrast, edge, surface integrity, unmarked colour, processing, mechanical function, durability and cycle time must be evaluated together.
Material Strategy
Use Black Titania as application-specific screening candidates. The list is not a performance ranking and does not establish equivalence between chemistry families.
- Freeze the host grade, colour, thickness, geometry and acceptance criteria.
- Normalize active-content and supplied-form differences or explain why another comparison basis is used.
- Screen loading and laser variables in a bounded matrix and preserve failed runs.
- Confirm the selected window across relevant lots, parts, tools and exposures.
Recommended Architectures
| Architecture | Use when | First validation gate |
|---|---|---|
| Matched baseline | The current material, colour and laser recipe require a reproducible reference. | PET optical-formulation response |
| Bounded screening ladder | Loading, supplied form, colour or delivered laser variables must be separated. | PET grade and drying; transparent or opaque state; crystallinity and nucleation; pigment or filler; optics and mark acceptance |
| Production confirmation | A candidate window must transfer across lots, geometry, tools or lifecycle exposures. | Margin, repeatability, failures and requalification triggers |
Controls That Must Stay Visible
| Order | Control | Review rule |
|---|---|---|
| 1 | PET grade and drying | Hold the other declared formulation, process, geometry and measurement conditions constant before attributing an effect. |
| 2 | transparent or opaque state | Hold the other declared formulation, process, geometry and measurement conditions constant before attributing an effect. |
| 3 | crystallinity and nucleation | Hold the other declared formulation, process, geometry and measurement conditions constant before attributing an effect. |
| 4 | pigment or filler | Hold the other declared formulation, process, geometry and measurement conditions constant before attributing an effect. |
| 5 | optics and mark acceptance | Hold the other declared formulation, process, geometry and measurement conditions constant before attributing an effect. |
Measurement & Validation
Primary response: PET optical-formulation response.
Method: Compare final-thickness specimens with recorded drying, crystallinity and colour; measure unmarked optics, mark contrast, edge and damage.
Report the unit or grade together with instrument or verifier geometry, specimen state, conditioning, repeats, distribution or uncertainty, failures and the acceptance limit. A scanner pass, photograph or supplier representative value is not a substitute for the declared method.
Qualification Boundary
- Record exact material and lot identities, active-content basis, carrier and colour package.
- Record compounding, drying, moulding, thickness, surface and geometry.
- Record source wavelength, pulse state, spot or focus, speed, hatch, passes, field and calibration.
- Measure marked and unmarked controls using the declared method.
- Confirm production and lifecycle variation, then define requalification triggers.
Primary Sources and Standards Boundary
- ISO/CIE 11664-4:2019 — CIE 1976 L*a*b* colour space — Defines CIELAB calculation; instrument geometry, illuminant, observer, aperture and specimen state must accompany results.
Related Products
Related Applications
Related Comparisons
No reviewed comparison page is required for this decision. Keep candidate comparisons inside a matched test matrix.
Downloads & Engineering Support
Need to apply this boundary to a grade, formulation, test method, or production route? Discuss it with the Aurexene Materials Engineering Team.