Technical Insight
Laser Marking Security Seals and Tamper-Evident Plastic Tags
Candidate controls include copper hydroxy-phosphate (BCHP) and Antimony Tin Oxide (ATO). A security-seal mark must remain readable without weakening the seal or obscuring the intended tamper evidence; qualify both identification and mechanical function.
Author: Aurexene Materials Engineering Team · Last updated: 2026-08-28
Quick Answer
A security-seal mark must remain readable without weakening the seal or obscuring the intended tamper evidence; qualify both identification and mechanical function.
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
A security-seal mark must remain readable without weakening the seal or obscuring the intended tamper evidence; qualify both identification and mechanical function.
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
Small flexible sections concentrate strain, while local laser heat and absorber loading can alter surface relief, stiffness or crack initiation.
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
Deeper marks may resist abrasion but reduce section margin; lighter marks preserve mechanics but can lose field readability.
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 BCHP and ATO 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. | Tamper-seal identification and function |
| Bounded screening ladder | Loading, supplied form, colour or delivered laser variables must be separated. | seal material and geometry; mark depth and location; code or serial layout; abrasion exposure; tamper function |
| 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 | seal material and geometry | Hold the other declared formulation, process, geometry and measurement conditions constant before attributing an effect. |
| 2 | mark depth and location | Hold the other declared formulation, process, geometry and measurement conditions constant before attributing an effect. |
| 3 | code or serial layout | Hold the other declared formulation, process, geometry and measurement conditions constant before attributing an effect. |
| 4 | abrasion exposure | Hold the other declared formulation, process, geometry and measurement conditions constant before attributing an effect. |
| 5 | tamper function | Hold the other declared formulation, process, geometry and measurement conditions constant before attributing an effect. |
Measurement & Validation
Primary response: Tamper-seal identification and function.
Method: Test actual seals for code or text readability, surface damage and the declared opening, break or tamper response before and after conditioning.
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/IEC 15415:2024 — two-dimensional bar-code quality — Defines measurement and grading methods for 2D symbols; report grade with the method conditions required by the applicable specification.
- ISO/IEC 15416:2025 — linear bar-code quality — Defines measurement and grading methods for linear symbols; scanner success alone is not a complete verifier result.
- GS1 DataMatrix Guideline — Explains symbol construction and verification context; the governing application specification still controls acceptance.
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.