High laser absorption does not guarantee good marking

Laser marking additives are often evaluated based on their optical absorption at specific laser wavelengths.   However, high absorption alone does not ensure effective or consistent laser marking performance in real polymer systems.

What laser marking additives must actually do

A laser marking additive must efficiently convert absorbed laser energy into localized thermal or chemical changes within the polymer matrix.   This process depends on more than absorption intensity.

Why high-absorption additives fail in practice

Poor energy conversion efficiency

Some additives absorb laser energy but dissipate it without generating sufficient localized heating.   As a result, visible marking contrast is weak or inconsistent.

Incompatibility with polymer matrices

Laser additives that are poorly dispersed or chemically incompatible with the host polymer fail to generate uniform marking, even if absorption is high.

Thermal diffusion and marking blur

If absorbed energy spreads too quickly through the matrix, the marking becomes blurred or shallow, reducing readability and contrast.

Key parameters beyond absorption

• Energy-to-heat conversion efficiency

• Thermal response time

• Dispersion quality in the polymer

• Compatibility with processing temperatures

Engineering conclusion

Effective laser marking requires a balanced combination of absorption, energy conversion, and material compatibility.   Focusing on absorption alone often leads to disappointing real-world performance.

Related Material

• Laser Marking Additives for Plastics