Lazov, Lyubomir

2023, Lazov, Lyubomir, Teirumnieks, Edmunds, Emil Yankov, Nikolay Angelov, Adijāns, Imants, Antons, Pacejs

In this study, an experiment was conducted to change the technological properties of the surface by infra-red laser marking. The influence of power, speed and raster step was investigated. These parameters during laser marking of AISI 304L steel have a significant change on the microhardness and surface roughness. It was found that high stiffness is achieved at higher powers and small pitch. An analysis of the results showed that as the raster step increases, the roughness of the marked sample decreases. The influence of linear energy density and overlap factor on the process was also investigated. The microhardness of the treated surfaces increases with an increase in the linear energy density and the overlap coefficient, and in the first case the dependence is almost linear, and in the second - non-linear.

2021, Lazov, Lyubomir, A Snikeris, I Balchev, Teirumnieks, Edmunds

Laser marking and engraving has developed in many ways into an attractive process for identifications of consumer goods made of plastic. It is a quick and inexpensive process that offers a variety of flexible options for designing identification products (barcodes, security information, codes). This report examines the possibility of marking PVC products used in the electronics industry with different colors using a CO2 laser technological system. The functional dependences of the width and depth of the marking lines on the main technological parameters – average power and processing speed, are analyzed. The analysis aims to help determine the optimal working intervals for marking and engraving by the bar coding method, as well as for the coding and reading of information on household PVC products used by visually impaired people. The analysis further aims to help determine the optimal operating intervals of speed and power when choosing a given geometry of the ablation zone in marking and engraving products for different users.

2023, Emil Yankov, Lazov, Lyubomir, Teirumnieks, Edmunds, Nikolay Angelov, Adijāns, Imants, Antons, Pacejs

In this research, an experiment was conducted to change the technological properties of the surface by laser marking. The influence of the speed v of 50 mm/s, 75 mm/s and 100 mm/s and the raster step Δx from 20 µm to 80 µm at a constant average power P = 19.2 W and pulse duration τ = 4 ns was investigated. These parameters during the laser marking of AISI 304L steel have a significant change in microhardness and surface roughness. High hardness was found to be achieved at higher powers and small pitch. Analysis of the results showed that as the raster step increases, the roughness of the marked sample decreases. The effect of linear energy density and overlap factor on the process was also investigated. The microhardness of the machined surfaces increases with an increase in the linear energy density and the overlap coefficient, in the first case the dependence is almost linear, and in the second - nonlinear. Varying the marking speed and raster pitch in laser surface texturing of AISI 304L steel has a significant effect on the surface hardness and roughness, changing HV from 260 HV to 766.5 HV and Ra from 1.75 µm to 4.3 µm, respectively, which are the subject of the present analysis. research.

2019, Lazov, Lyubomir, Teirumnieks, Edmunds, Teirumnieka, Ērika, Pavel Cacivkin, Nikolay Angelov, Tsanko Karadzhov

The laser marking has been established in recent years as one of the modern innovative methods for marking many industrial products. The report examines a new laboratory exercise for the subject Laser Technology, studied in some technical universities. A new approach is proposed to determine the contrast of the laser marking process. Described is the purpose and the main tasks as well as the new skills and knowledge that students can exercise through this laboratory exercise. Students implement a test matrix consisting of squares of a certain size using the raster marking method. Through the new laboratory exercise, students can explore and analyze the dependencies of the contrast of laser markings on different dimensions influencing the technological process. The capabilities of the new approach allow learners to become more familiar with the factors that influence the modern process of laser marking widely used in modern industry. The results of the experiments the students summarize using a new modern digital approach to analyze the contrast against the background of the marked surface. From the experimental graphical dependencies of the variation of the power and speed contrast, they draw conclusions about the optimal process parameters.

2016, Pavels Narica, Teilāns, Artis, Lazov, Lyubomir, Pavels Cacivkins, Teirumnieks, Edmunds

Method allows for modelling of the complex process of laser pulse energy distribution over flat work surface. The process of calculating the correct result does not use common lasing formulas but instead employs the mathematical model of matrix multiplication of three input matrices representing a pulse model, a line model, and a plane model. The pulse model represents the distribution of planar energy densities within the laser pulse. The line model represents the distribution of pulses within the line. The plane model represents the distribution of lines within the plane. Because mathematical model is implemented within a spreadsheet processor, its size can be adjusted as needed and it can be instantiated multiple times for simultaneous modelling of different input parameters.

2021, Pēteris Čeirs, Adijāns, Imants, Lazov, Lyubomir

A number of policies and standards regarding food safety issues and quality management have been established for the food industry. One of these requirements is related to the marking of food products describing the expiration date, content and quality.  The report examines the possibility of using laser technology to mark chicken eggs. The contrast of the laser marking is the main criterion for determining its quality. The study examines the functional dependences of the contrast on the main technological parameters of the marking process: laser output power (7 – 20.3 W) and processing speed (50 - 300 mm/s). As a result of the research, optimal parameters for marking with a technological laser system CO2 have been determined.