Laser marking of non-ferrous metal and alloy products using ultradense barcodes: process features

Abstract

This paper describes the results of a study that looked at the effect of laser pulses on the surface of copper, aluminium and titanium alloys during laser marking. A series of studies has been carried out aimed at developing a process that would enable putting high-density barcodes on the surface of nonferrous metals in order to keep a great amount of data about the products and to protect them from counterfeiting. The paper explains why nanobarcodes are unique and how they outperform common standard markings. The colours of the markings are defined by the characteristics of the oxide films that form as the result of surface modification by laser pulses. They include the thickness of the oxide film and its phase and chemical compositions, which impact the chemical composition of the alloy and the temperaturetime modes of the laser marker. To ensure quality in marking, the authors selected the most contrasting tones of the resultant markings. Sets of such colours are presented that were obtained on the studied materials. The paper also describes the results of optical and electronic microscopy of the oxide films of the resultant markings demonstrating the structure of furrows and craters, which are the result of surface melting and evaporation under laser treatment. The paper analyzes the quality of the resultant nanobarcodes in terms of their readability and decodability by means of special software.