13366 KB0 KB0 KB2022Kalin, MitjanPušavec, FranciSterle, LukaXXVIII, 142 str., 2 f. pril., 31 cmCOBISSID:108222723PID:https://repozitorij.uni-lj.si/IzpisGradiva.php?id=136725URN:URN:NBN:SI:doc-OH9ZWE88enL. Sterlevisokošolska delacryogenic machiningcutting temperatureDisertacijedissertationsintegriteta površinekriogeno odrezovanjeOdrezovanjerezalna temperaturasolid lubricantssurface integritytrdna mazivatribologijatribologytribometerFundamental characterization of cryogenic machining by applying solid lubricants| dissertation|Cryogenic machining based on liquid carbon dioxide (LCO2) represents a sustainable and clean way of manufacturing and enables the substitution of conventional metalworking fluids such as water-based emulsions. In machining processes, LCO2 is a cooling medium to which various lubricants are added to improve lubrication properties. Solid lubricants can reduce friction even in the most demanding conditions. The concept of implementing solid lubricants in LCO2 to achieve cooling and lubricating properties is thus a novelty in the field of cryogenic machining. Within the scope of the doctoral thesis, a single-channel system for the supply of oil- and solid-lubricated LCO2 was developed. The system implementation for feeding the mixture through the spindle and the tool directly into the machining process was carried out. A special tribometer was used to analyse the lubrication properties of different cooling/lubrication strategies, including pure LCO2 and oil- and solid-lubricated LCO2. Milling and drilling processes were used to determine the basic properties of cryogenic machining based on tool life, integrity of the machined surface, cutting forces and cutting temperature. Predictive models were developed to optimise cryogenic machining for sustainable manufacturing by reducing the consumption of coolants and lubricants. Analysis of the machined surfaces with an electron beam microscope proved the benefit of using solid lubricants in terms of the integrity of the machined surface and the final cleanliness of the partKriogeno odrezovanje na osnovi kapljevitega ogljikovega dioksida (LCO2) predstavlja trajnostno in čisto obdelavo kovin in omogoča substitucijo konvencionalnim hladilno mazalnim sredstvom, katere so ponavadi emulzije vode in olja. LCO2 v odrezovalnih procesih predstavlja hladilni medij, ki mu dodajamo različna maziva za izboljšanje mazalnih lastnosti. Trdna maziva zmanjšujejo trenje tudi v za uporabo olj neprimernih pogojih. Zasnova implementacije trdnih maziv v LCO2 za doseganje hladilnih in mazalnih lastnosti tako predstavlja novost na področju kriogenega odrezovanja. V sklopu doktorske naloge je bil razvit enokanalni sistem za dovod mešanice LCO2 ter tekočega ali trdnega maziva. Izvedena je bila implementacija sistema za dovod mešanice skozi vreteno obdelovalnega stroja ter orodja direktno do rezalnega procesa. Z uporabo namensko razvitega tribometra so bile analizirane mazalne lastnosti različnih pristopov mazanja in hlajenja, vključujoč čisti LCO2 ter mešanice LCO2 ter tekočega ali trdnega maziva. Na procesih frezanja in vrtanja so bile določene osnovne karakteristike kriogenega odrezovanja na podlagi obstojnosti orodja, integritete obdelane površine, rezalnih sil ter rezalne temperature. Izdelani so bili napovedovalni modeli za optimizacijo kriogenega odrezovanja, kateri omogočajo trajnostno obdelavo preko zmanjšanja porabe hladilnega in mazalnega medija. Analiza obdelanih površin z elektronskim vrstičnim mikroskopom je dokazala smiselnost uporabe trdnih maziv iz vidika integritete obdelane površine ter končne čistosti izdelkaTEXTvisokošolska delatheses and dissertationsSlovenian National E-content AggregatorNational and University Library of SloveniaUniverza v Ljubljani, Fakulteta za strojništvo