Stefan Gaspar

Dr. Stefan Gaspar


Research Focus & Metrics

Academic Career Length

14Years (2013-Present)

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

Representative Publications

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26 January 2021 in Sustainability
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JKJakub Kaščak
Jakub Kaščak
SGStefan Gaspar
Stefan Gaspar
JPJán Paško
Ján Paško
Jozef HusárJozef Husár
Jozef Husár
Lucia KnapcikovaLucia Knapcikova
Lucia Knapcikova
The application of topological optimization is currently considered one of the current trends. Because the shape of the components thus designed is the result of a design generated based on external influences acting on the model, their form can be considered almost optimal. For example, the extent of material savings resulting from shortening production cycles and reducing energy requirements is significant. Due to the way models are produced by layering the material in 3D printing, this technology makes it possible to get a little closer to the models’ optimal shape, for example, to produce prototype models for the production of injection moulds. The amazing amount of plastic and composite materials that this technology brings allows for a variable change in manufactured models based on requirements or external influences. These materials also include a group of materials and composite materials that are classified as biodegradable due to their composition. This fact, combined with the possibility of achieving the most optimal shape of components, contributes to reducing the environmental burden of such oriented production. This work presents the opportunities for modifying topological optimization outputs based on operating parameters and limits of additive production equipment fused deposition modeling (FDM). It gives the possibilities of using alternative ecological materials, their direct application, and the impact on creating models with the help of this technology. The final phase represents the result of the optimization process of the subsystem mechanism and the influence of the mechanical properties of biodegradable materials on the production process and the energy intensity of production. The aim of this work is to point out the fact and possibilities of using composite materials on a natural basis and their possible impact on reducing the environmental burden.

25 March 2021 in Applied Sciences
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Journal Article
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JKJakub Kaščak
Jakub Kaščak
SGStefan Gaspar
Stefan Gaspar
JPJán Paško
Ján Paško
Lucia KnapcikovaLucia Knapcikova
Lucia Knapcikova
Jozef HusárJozef Husár
Jozef Husár
JTJozef Torok
Jozef Torok
This article presents the variability of Fused deposition modelling (FDM) technology and the possibilities of its use in the design and implementation of a prototype atypical device. The assumptions of the behaviour of individual components and subsystems of the design result from an extensive application of the finite element method and motion analysis of subsystems and various parts of the structure. The use of this method to such an extent accelerated the design process and its implementation. The proposal itself reflects the current state of this technology and its focus is on improving sustainable development. As is generally known, great efforts are currently being made to reduce plastic waste volume and its environmental burden. The proposed concept is modified to replace the final treatment of the top layers of the models, called “ironing” by non-planar layering of material. At the same time, it points out the advantages of this method in reducing energy requirements and the time required to produce models. The conclusion is a conceptual design of a printhead for a proposed prototype, designed to use recycled FDM, intending to streamline the possibility of recycling with little serial and piece production. This process thus closes the circle of opportunities published by us, which in the future can contribute to the optimisation of this technology towards increasing the efficiency of resource use, reduction of energy demands and environmental burden.

14 December 2020 in Processes
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Tibor KrenickyTibor Krenicky
Tibor Krenicky
MSMilos Servatka
Milos Servatka
SGStefan Gaspar
Stefan Gaspar
Jozef MascenikJozef Mascenik
Jozef Mascenik
The paper aims to study the surface quality dependency on selected parameters of cuts made in Hardox™ by abrasive water jet (AWJ). The regression process was applied on measured data and the equations were prepared for both the Ra and Rz roughness parameters. One set of regression equations was prepared for the relationship of Ra and Rz on cutting parameters—pumping pressure, traverse speed, and abrasive mass flow rate. The second set of regression equations describes relationships between the declination angle in kerf as the independent variable and either the Ra or the Rz parameters as dependent variables. The models can be used to predict cutting variables to predict the surface quality parameters.


29 December 2020 in Applied Sciences
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TCTomáš Coranič
Tomáš Coranič
SGStefan Gaspar
Stefan Gaspar
JPJan Pasko
Jan Pasko
The present paper is focused on the issue of creating residual stresses in the manufacturing of the moulded parts for injection moulding machines using DMLS technology. Thus, fractures and cracks can cause deformations and geometric inaccuracies in the final part. Moreover, they pose a potential damage risk to the machine itself. The simulation tools for the analysis of the Direct Metal Laser Sintering (DMLS) process were used to expose the critical points of the original monolithic shaped insert in which the highest stresses during the manufacture occur. Subsequently, an alternative solution was created via the optimization of the internal topology. This solution was analysed, and in terms of strength characteristics, compared to the original model in order to ensure the proper function and durability of the manufactured part. The present study was created in cooperation with a company engaged in the production of injection moulds. The internal topology optimization of the part itself is used in combination with the appropriate orientation of the model in the workspace, unlike other research in the given field, where either the model orientation optimization or the support structure is used in this design. However, except for the mentioned reduction of residual stresses, it has a positive effect on mechanical properties, reducing material consumption and savings in time; thus, the obtained results can be applied to other methods of additive manufacturing.

11 August 2020 in Materials
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JMJan Majerník
Jan Majerník
SGStefan Gaspar
Stefan Gaspar
JKJán Kmec
Ján Kmec
MKMonika Karková
Monika Karková
Jozef MascenikJozef Mascenik
Jozef Mascenik
The mechanical properties of die castings correlate with the inner structure of a casting, distribution of the eutectic phases, and with the content and distribution of porous cavities in the casting volume. This submitted paper deals with the issue of the possibility to influence the basic parameters affecting the quality of castings through structural modifications of the gating system. The structural parameter under assessment is the gate height. In the case of the diverse height of the gate, five sets of castings were produced. The individual sets of castings were subjected to examination of selected mechanical properties, i.e., of permanent deformation and surface hardness. At the same time, the individual sets of castings were subjected to metallographic examination of the eutectic structure of the casting. It was proved that the gate height influences the aforementioned properties of the castings and significantly affects the ratio of the eutectic phases in the volume of the casting. The conclusion describes the mutual correlation between the gate structure, the mechanical properties of the casting, and its structural composition.