Ústav automatizace a informatiky
Browse
Recent Submissions
- ItemProject Management in the Time of VUCA: Threat or Opportunity?(University of Hradec Králové, 2024-04-10) Košťálová, Jana; Doskočil, Radek; Širáňová, Lenka; Lacko, BranislavThis study addresses the "projectification of society" and its alignment with the VUCA framework (Volatility, Uncertainty, Complexity, Ambiguity). Four widely used international project management standards—PMI, IPMA, PRINCE2, and PM2—are evaluated for their suitability in the VUCA environment. The research employs a multicriteria approach, specifically the Weighted Sum Approach method, considering factors like volatility, uncertainty, complexity, and ambiguity. The selected standards are scrutinized based on their adaptability to VUCA challenges, with a focus on PMBOK, IPMA, PRINCE2, and PM2. The seventh edition of the PMBOK has been evaluated on the first position. The study emphasizes the crucial role of selecting an appropriate project management standard for success in navigating the dynamic VUCA world. The results confirmed this and brought a number of recommendations for managing projects in a VUCA environment.
- ItemAnalysis of the machinability of copper alloy Ampcoloy by WEDM(MDPI, 2020-02-11) Mouralová, Kateřina; Beneš, Libor; Prokeš, Tomáš; Bednář, Josef; Zahradníček, Radim; Jankových, Róbert; Fries, Jiří; Vontor, JakubThe unconventional technology wire electrical discharge machining is widely used in all areas of industry. For this reason, there is always an effort for efficient machining at the lowest possible cost. For this purpose, the following comprehensive study has been carried out to optimize the machining of the copper alloy Ampcoloy 35, which is particularly useful in plastic injection moulds. Within the study a half-factor experiment of 25-1 with 10 axial points and 7 central points of a total of 33 rounds was carried out, which was focused on the response monitoring of the input factors in the form of the machine parameters setup: gap voltage, pulse on time, pulse off time, discharge current, wire speed. Based on the study of the response in the form of cutting speed and surface topography, their statistical models were created, while the optimal setting of machine parameters was determined to maximize the cutting speed and minimize the topography parameters. Further, a detailed cross-sectional analysis of surface and subsurface layer morphology was performed using electron microscopy including the chemical composition analysis. In order to study microstructural changes in the material at the atomic level, a lamella was created, which was then studied using a transmission electron microscope.
- ItemAnalysis of Machinability and Crack Occurrence of Steels 1.2363 and 1.2343ESR Machined by Die-Sinking EDM(MDPI, 2020-04-19) Mouralová, Kateřina; Beneš, Libor; Bednář, Josef; Zahradníček, Radim; Prokeš, Tomáš; Fries, JiříDie-sinking electric discharge machining (EDM) is an indispensable technological operation, especially in the production of molds and all internal and external shapes and cavities. For this reason, the effect of machine parameter settings (open-voltage, pulse current, pulse on time, and pulse off time) on the machining of two types of steels, 1.2363 and 1.2343ESR, was carefully investigated using graphite or copper electrodes in 10mm × 10 mm or 100mm × 100 mm shapes. For this purpose, a two-level half factor experiment was performed with one replication at the corner points and two replications at the central points, with a total of 80 rounds. The subject of the evaluation was the topography and morphology of machined surfaces including a detailed analysis of surface and subsurface defects in the form of cracks including the creation of regression equations describing the probability of crack occurrence. Furthermore, a study of the local hardness change in the subsurface area was performed, and lamellas were also made and studied by transmission electron microscopy. It has been found that by using die-sinking EDM, it is possible to effectively predict the probability of cracking on machined surfaces and also on machine 1.2363 and 1.2343ESR steels with a very good surface quality of Ra 1.9 and 2.1 µm using graphite electrodes. These findings will ensure the production of parts with the required surface quality without cracks, which is a crucial aspect for maintaining the required functionality and service life of the parts.
- ItemPrecision Machining of Nimonic C 263 Super AlloyUsing WEDM(MDPI, 2020-06-24) Mouralová, Kateřina; Beneš, Libor; Bednář, Josef; Zahradníček, Radim; Prokeš, Tomáš; Fiala, Zdeněk; Fries, JiříWire electrical discharge machining (WEDM) is an unconventional and very efficient technology for precision machining of the Nimonic C 263 super alloy, which is very widespread, especially in the energy, aerospace and automotive industries. Due to electrical discharge, defects in the form of cracks or burned cavities often occur on the machined surfaces, which negatively affect the correct functionality and service life of the manufactured components. To increase the efficiency of the machining of Nimonic C 263 using WEDM, in this study, extensive design of experiments was carried out, monitoring input factors in the form of machine parameters like Pulse off time, Gap voltage, Discharge current, Pulse on time and Wire feed, the output of which was comprehensive information about the behaviour of such machined surfaces, which allowed the optimization of the entire machining process. Thus, the optimization of the Cutting speed was performed in relation to the quality of the machined surface and the machining accuracy, as well as an analysis of the chemical composition of the machined surfaces and a detailed analysis of the lamella using a transmission electron microscope. A detailed study of the occurrence of surface or subsurface defects was also included. It was found that with the help of complex optimization tools, it is possible to significantly increase the efficiency of the machining of the Nimonic C 263 super alloy and achieve both financial savings in the form of shortened machine time and increasing the quality of machined surfaces.
- ItemStudy of micro structural material changes after WEDM based on TEM lamella analysis(MDPI, 2020-06-07) Mouralová, Kateřina; Zahradníček, Radim; Beneš, Libor; Prokeš, Tomáš; Hrdý, Radim; Fries, JiříWire electrical discharge machining is an unconventional machining technology that is crucial in many industries. The surface quality of the machined parts is carefully monitored, but the condition of the subsurface layer also plays a crucial role, especially in case of defects occurrence such as cracks or burnt cavities. The subsurface layer of individual materials is affected differently due to wire electrical discharge machining. For this reason, this study was carried out focusing on a detailed analysis of transmission electron microscope (TEM) lamellae made of Ti-6Al-4V titanium alloy, AlZn6Mg2Cu aluminium alloy, pure molybdenum, Creusabro 4800 steel, and Hardox 400 steel. The attention was first of all paid to the concentration and distribution of individual elements in the recast layer and also in the base material, which was often affected by Wire electrical discharge machining. Further, a diffraction analysis was performed for each TEM lamella in the adhesive area and in the area of the base material. In order to assess the macro-effects on the machined material, the analysis of the topography of the machined surfaces and the morphology analysis were performed using electron microscopy.