Technical Guide: Laser Marking Additives for Plastics & Glass (BCHP vs ATO vs ZrN)

Mechanism-first guide to comparing laser marking additive approaches for plastics and glass. Covers BCHP dark-mark systems, absorber-driven marking (ATO), and ZrN-enabled glass workflows, with practical selection logic, applications, process variables, and FAQs.

1) The “Gray Mark” Problem

A common failure mode in laser marking is a low-contrast “gray mark” on light plastics (PP, PE, PA) when the goal is a crisp black code. On dark polymers the challenge is reversed: creating a bright, readable mark without damaging the surface.

2) Screening and Performance Data Context

In practice, candidate additives are evaluated by comparative screening under fixed conditions (substrate grade, laser settings, additive loading). Performance discussion here reflects relative behavior under typical screening protocols; results should always be confirmed on your production substrate and process window.

3) Chemistry and Functional Comparison

BCHP (Basic Copper Hydroxyl Phosphate) — Dark Mark Systems

BCHP-based laser additives can increase apparent mark darkness on light-colored plastics by inducing localized additive and matrix changes under near-infrared laser energy. This approach is commonly selected when high optical contrast is required on white or natural substrates.

Internal references: LaserMark-C,LaserMark-W.

ATO (Antimony Tin Oxide) — Absorber-Driven Marking

ATO functions as a near-infrared absorber to couple laser energy into the surface. Its final appearance on a given polymer depends on resin type, pigment/filler package, loading, and process variables. It can be effective in engineered plastics and electronics parts when qualified appropriately.

Internal reference: LaserMark-E.

Light Marks on Dark Plastics

When a light (white or bright) mark is needed on dark substrates, foaming/light-scattering mechanisms can be effective. Such systems create micro-porosity to scatter light, and outcomes vary with polymer chemistry and laser conditions.

Internal reference: LaserMark-SF.

ZrN (Zirconium Nitride) — Glass Marking Workflows

Many glasses are transparent at common fiber-laser wavelengths; ZrN-based absorbers convert near-infrared energy to localized heat, enabling controlled surface effects. Careful tuning is essential to balance readability and avoid substrate damage such as cracking.

Internal reference: LaserMark-G.

4) Typical Applications

Laser marking additives are used in a variety of practical contexts, including:

• QR/Datamatrix traceability on molded parts

• Permanent part identification on housings and connectors

• ESD trays and conductive plastics with functional identification

• Automotive and appliance components requiring durable codes

• Glass bottles, containers, and technical glass components

5) Process Variables to Control

Stable marking results depend on consistent control of:

• Polymer grade and base color (including pigments and fillers)

• Additive loading range and dispersion quality

• Laser wavelength, power, speed, and focus

• Part geometry and surface finish

6) Selection Logic (If / Then)

• If you need high-contrast dark marks on white or natural plastics, then start screening with a BCHP-based system such as LaserMark-C.

• If you need bright light marks on dark plastics, then evaluate a foaming/light-scattering system such as LaserMark-SF.

• If electronics components require clean, stable markings, then consider an electronics-grade marking additive such as LaserMark-E.

• If glass substrates are involved, then consider an absorber-enabled workflow such as LaserMark-G and tune parameters carefully.

FAQ

What causes low-contrast “gray marks” on white plastics?

Low contrast often results from a mismatch between additive mechanism, polymer response, and laser settings, leading to insufficient optical density or poor edge definition. Mapping a stable process window on the actual substrate is critical.

Is ATO always worse than BCHP for marking?

Not necessarily. ATO is an absorber approach and can perform well in certain polymers and engineered applications. BCHP-based systems are often selected for high-contrast dark marking on light substrates, but qualification should be application-specific.

How do I choose between dark-mark and light-mark systems?

Use dark-mark systems for light substrates and light-mark (foaming/scattering) systems for dark substrates. Validate by readability (QR/Datamatrix), abrasion resistance, and repeatability in your production process.

Can fiber lasers mark glass without absorbers?

Some glass marking methods exist, but transparent substrates often benefit from absorber/coating workflows to improve controllability. Tuning laser parameters is important to balance readability and avoid micro-cracking.

Scope & Validation

Discussed mechanisms and comparisons are relative and context-dependent. Performance varies by material formulation, processing history, part geometry, and laser configuration. Always validate under your specific production and quality requirements.