Color Laser Marking: Repeatability, Stability and Resistance Against Mechanical, Chemical and Environmental Effects

Hamid Roozbahani,Antti Salminen,Heikki Handroos,Marjan Alizadeh

doi:10.1109/access.2020.3040744

Abstract

In this paper, utilizing the technology of color laser marking of stainless steel in industrial productions is investigated from the perspective of repeatability and stability of produced color markings. The color laser marking has remarkable advantages over conventional metal coloring methods; however, in order to implement this technology in industry, the reliability, stability and quality of resulting markings must be endorsed. For this purpose, an AISI 304 color palette made up of fifteen colors was evolved. The dependence of produced colors on different laser processing parameters were analyzed. Afterward, the produced colors were tested utilizing optical, scanning electron and atomic force microscopy, and the configuration of oxide films was specified through Raman spectroscopy. The obtained colors had proper uniformity, brightness, and cover almost all spectral regions. Also, color standardization and palette repeatability test were performed by assessing and evaluating the reflectance spectra of the formed colors. The color palette demonstrated high repeatability for all colors except for one specific color. Moreover, the stability of color markings in terms of environmental, mechanical and chemical resistance was investigated. The resulting colors showed high resistance in most of the environmental conditions; however, exposure to very high temperatures and extreme humidity ( $100^{\circ }\text{C}$ , 90%) and low temperature and extreme humidity ( $- 40^{\circ }\text{C}$ , 90%) leads to deterioration of few colors. Color marks showed high hardness and excellent mechanical stability to external impacts and outstanding resistance to various chemicals, excluding acidic solutions and salts.

Highlights

Product marking is an essential part of the production cycle, which provides the necessary information about the product and serves as a marketing tool to draw consumers’ attention to a specific product
The potential of utilizing color laser marking technology in industrial production is discussed in detail
Twenty color palettes of stainless steel AISI 304 was developed based on the performed analysis

Summary

Introduction

Product marking is an essential part of the production cycle, which provides the necessary information about the product and serves as a marketing tool to draw consumers’ attention to a specific product. Various types of marks are applied to products, permanent markings are more desired. Different techniques, including indenting, electrochemical etching, engraving, dot peen, and laser marking, can be utilized to create permanent marking. The laser marking method is efficient, non-contact, and applies to both metallic and nonmetallic types of surfaces. It does not require extra supplements or solvents and does not produce waste; it is environmentally sustainable. Color laser marking has been known for a long time, so, many researches have been conducted about using different kinds of laser sources, effects of environmental conditions on the results and analysis of physical and chemical properties of the surfaces

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Conclusion