The Formation of Contrasting Nanofilms on a Metal Surface for Bar Coding

Abstract

Laser marking is a universal method of applying information to the products surface. Colored oxide films form on metal surface during a thermal exposure. The degree of steel heating influences the film thickness. Corrosion-resistant steel AISI 304 samples were laser-marked with a MiniMarker 2-20A4 precision laser complex. The contrast of the barcodes on a metal area depends on the surface roughness and the chemical composition of the steel. Fe2O3, Fe3O4 oxides forms the greatest contrast. RGB indicators are used to assess contrast. Study results may be applicable to increase the QR code contrast thereby contributing to the improvement of laser marking technology while preserving economic efficiency.

Temperature Influence on Readability of the QR-Code on Titanium Alloy

“…But with further heating, the dark oxides degrade, so that the readability resumes. Figure 6 shows the change in contrast depending on the sample heating temperature [19].…”