Investigation of the Contrast Changing of Copper Surfaces in the Laser Marking Process

Abstract The surface treatment for product marking indicates a significant impact on the recognition of a product by an electronic reader for both the manufacturer and the end customer. This is achieved by receiving a unique code, which must be robust and durable over time. This paper investigates the influence of technological parameters speed, raster step, pulse duration, power density and effective energy on the marking of copper samples with Yb-doped fiber and CuBr MOPA lasers. The studies were conducted in two groups: on the one hand, for pulses with 100 ns and 200 ns duration for the fiber laser and on the other hand, for pulses with 30 ns duration for the copper bromide laser. The speed change in these experiments varied across the interval from 10 mm/s to 80 mm/s. The raster step intervals are from 3 µm to 20 µm for the fiber laser and from 3 µm to 27 µm for the CuBr laser. The results are compared at different pulse durations of the fiber laser and the role of the wavelengths of the two types of lasers on the technological process is investigated. Optimal intervals for visual perception of information have been determined for the effective energy in raster marking with Yb-doped fiber and CuBr lasers. For the fiber laser it is from 17.4 kJ/cm² to 43.1 kJ/cm² and for the copper bromide laser from 9.90 kJ/cm² to 43.1 kJ/cm².