Department of Machining, Assembly and Engineering Metrology - dep.346, VSB - Technical University of Ostrava, Ostrava, Moravskoslezský Kraj, Czech Republic
Prof. Dr. Marek Sadílek
Department of Machining, Assembly and Engineering Metrology - dep.346, VSB - Technical University of Ostrava, Ostrava, Moravskoslezský Kraj, Czech Republic
Although the abrasive waterjet (AWJ) has been widely used for steel cutting for decades and there are hundreds of research papers or even books dealing with this technology, relatively little is known about the relation between the steel microstructure and the AWJ cutting efficiency. The steel microstructure can be significantly affected by heat treatment. Three different steel grades, carbon steel C45, micro-alloyed steel 37MnSi5 and low-alloy steel 30CrV9, were subjected to four different types of heat treatment: normalization annealing, soft annealing, quenching and quenching followed by tempering. Then, they were cut by an abrasive water jet, while identical cutting parameters were applied. The relations between the mechanical characteristics of heat-treated steels and the surface roughness parameters Ra, Rz and RSm were studied. A comparison of changes in the surface roughness parameters and Young modulus variation led to the conclusion that the modulus was not significantly responsible for the surface roughness. The changes of RSm did not prove any correlation to either the mechanical characteristics or the visible microstructure dimensions. The homogeneity of the steel microstructure appeared to be the most important factor for the cutting quality; the higher the difference in the hardness of the structural components in the inhomogeneous microstructure was, the higher were the roughness values. A more complex measurement and critical evaluation of the declination angle measurement compared to the surface roughness measurement are planned in future research.
This contribution deals with the accuracy of machining during free-form surface milling using various technologies. The contribution analyzes the accuracy and surface roughness of machined experimental samples using 3-axis, 3 + 2-axis, and 5-axis milling. Experimentation is focusing on the tool axis inclination angle—it is the position of the tool axis relative to the workpiece. When comparing machining accuracy during 3-axis, 3 + 2-axis, and 5-axis milling the highest accuracy (deviation ranging from 0 to 17 μm) was achieved with 5-axis simultaneous milling (inclination angles βf = 10 to 15°, βn = 10 to 15°). This contribution is also enriched by comparing a CAD (Computer Aided Design) model with the prediction of milled surface errors in the CAM (Computer Aided Manufacturing) system. This allows us to determine the size of the deviations of the calculated surfaces before the machining process. This prediction is analyzed with real measured deviations on a shaped surface—using optical three-dimensional microscope Alicona Infinite Focus G5.
1 May 2017 in Tehnicki vjesnik - Technical Gazette
This article is interested about drilling the holes to the alloy wheels. Tested were drills to drilling holes for screws and service holes. For screw holes was tested the three-stage drill with inserts from polycrystalline diamond. Drilled are...
1 June 2018 in Advances in Science and Technology Research Journal
The article tackles the possibilities and effectiveness of different printing strategies on Easy 3D MAKER printer. This printer is printing with Fused Deposition Modeling (FDM) method. The operating software of the 3D printer offers various settings, which influence the quality and effecticity of...
In the field of additive manufacturing, Laser Powder Bed Fusion (LPBF) has become a good technique for manufacturing metallic parts. The aim of this investigation was to clarify how temperature, sliding speed, and load affected the tribological properties of SS316L that was made by LPBF. Test temperature, sliding velocity, and applied load all had a significant impact on sample wear rate as well as their Coefficient of Friction (COF), according to the data. Particular note: at a test temperature of 250 °C, wear rate and COF showed lower values compared to ambient temperature data. The oxide layer formed on the surface that served as a lubricant and reduced material deterioration. Moreover, increased normal loads and decreased sliding velocities were associated with an increasing trend in both COF and wear rate.