Gerhard Mitaľ

Dr. Gerhard Mitaľ

orcid

Research Focus & Metrics

Academic Career Length

11Years (2016-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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24 May 2019 in Applied Sciences
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Journal Article
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GMGerhard Mitaľ
Gerhard Mitaľ
Jozef DobranskyJozef Dobransky
Jozef Dobransky
Juraj RužbarskýJuraj Ružbarský
Juraj Ružbarský
ŠOŠtefánia Olejárová
Štefánia Olejárová
The paper is an evaluation of the surface roughness of various materials produced by water jet cutting (AWJ, abrasive water jet). A 3D laser profilometer developed at the Department of Design and Technical Systems Monitoring at our University was used in roughness measurement. To verify the values measured by the laser profilometer, another measurement was performed using a 2D contact roughness meter. The tests were done on aluminum and stainless-steel materials, respectively. Six samples were produced; three made of stainless steel and three made of aluminum. All samples were produced at a different feed rate of the cutting head. This was adapted to the different roughness required, per the manufacturer’s material data sheets. Varying rates of separation translated into different qualities of the surfaces under evaluation. The evaluated roughness parameters were Ra and Rz. Dependencies were plotted in the chart based on the values measured, which were then compared and evaluated.

11 April 2022 in Applied Sciences
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GMGerhard Mitaľ
Gerhard Mitaľ
Ivan GajdošIvan Gajdoš
Ivan Gajdoš
Emil SpišákEmil Spišák
Emil Spišák
JMJanka Majerníková
Janka Majerníková
TJTomáš Jezný
Tomáš Jezný
This study investigates how layer deposition in printing 3D models made of polyetherimide (PEI) using the fused filament fabrication (FFF) technique affects resistance of these models to abrasive wear. Samples made by additive manufacturing with different setting of build orientation and path generation strategy of extruded fibers were used in the experiment. The experiments were conducted on a tribometer according to the ASTM G65-16 standard. The friction force, normal force, and temperature in the contact area during the tribometer operation were measured using a strain gauge sensor. The tribometer allowed us to perform the tribological experiments using a rubber-coated or a metal disc without a lubricant in the so-called “dry” operation. Following the ASTM G65-16 standard, a rubber-coated disc and Fe3Al2 (SiO4)3 garnet abrasive were used for the wear resistance tests. The analysis of experimental data showed correlations among orientation selection, the strategy of layer deposition by the FFF technique, and the surface life in terms of abrasive wear. The results of this research also showed the suitability of the chosen building orientation and deposition strategy for part production by additive manufacturing, depending on the required tribological properties, such as the coefficient of friction (yield path) and wear behavior. Based on the results of the study, it is concluded that continuity of wear and friction force depends on the path traveled under the model production orientation. The size of wear (material loss) ranged from 0.451–0.809%. It was shown that the weight loss of the sample under loading was greater, on average, with the chosen fiber orientation strategy in the Z direction than in the X direction.

1 March 2018 in MM Science Journal
Verified
Journal Article
Closed access
Juraj RužbarskýJuraj Ružbarský
Juraj Ružbarský
GMGerhard Mitaľ
Gerhard Mitaľ

22 June 2023 in Materials
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Journal Article
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GMGerhard Mitaľ
Gerhard Mitaľ
Ivan GajdošIvan Gajdoš
Ivan Gajdoš
Emil SpišákEmil Spišák
Emil Spišák
The aim of this study was to investigate the effect of Fused Filament Fabrication (FFF) layer generation strategies on abrasive wear resistance and compare the material loss of PEI (polyetherimide) plastic specimens based on different specimen building strategies. The study also compares a newly proposed path generation strategy (parallel paths in layers with 0.25 mm displacement of alternate layers) with samples from a previous study where samples were printed without displacement of alternate layers, i.e., layers stacked perpendicularly to each other. The primary focus was on the weight loss due to abrasive wear before and after the test. The tests were conducted on a tribometer constructed according to ASTM G65/16 standards using dry sand. Two printing directions were examined: X (longitudinal) and Z (portrait) orientations. For X construction, three orientations of deposition path generation were utilized, resulting in three samples for each orientation (nine samples in total for X construction). The same approach was applied to Z construction, resulting in another nine samples. In total, 18 samples were produced and tested. The deposited infill path width was 0.5 mm, and the layer thickness used in printing was 0.254 mm. Garnet abrasive Fe3Al2(SiO4)3 was employed in this test. Analysis of the experimental data revealed a relationship between the construction method (X and Z orientations) and the variation in different orientations (1X–3X and 1Z–3Z). The research results can be categorized as overall and partial. The overall results indicate poorer wear resistance for 1X–3X and 1Z–3Z specimens, while the partial results illustrate the findings within each individual specimen.

13 October 2021 in MM Science Journal
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Journal Article
Closed access
GMGerhard Mitaľ
Gerhard Mitaľ
Emil SpišákEmil Spišák
Emil Spišák
PMPeter Mulidran
Peter Mulidran
Ľuboš KaščákĽuboš Kaščák
Ľuboš Kaščák
TJTomas Jezny
Tomas Jezny
The article deals with contact and non-contact evaluation of surface roughness created by water jet cutting technology (AWJ). Non-contact surface measurement was performed using an LPM laser profilometer. The values measured by the laser profilometry method were compared with the values measured by the contact method, the Mitutoyo SJ 400 roughness meter. Six samples were produced. Three in stainless steel and three in structural steel. In order to achieve a different surface topography, different feed rates of the cutting head were used on the samples, which was reflected in the quality of the resulting surface. The evaluated parameters were the average arithmetic deviation of the assessed profile and the largest height of the profile inequality.

27 September 2016 in MM Science Journal
Verified
Journal Article
Closed access
GMGerhard Mitaľ
Gerhard Mitaľ
Juraj RužbarskýJuraj Ružbarský
Juraj Ružbarský