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1.
Tool condition monitoring using machine tool spindle current and long short-term memory neural network model analysis
Niko Turšič, Simon Klančnik, 2024, original scientific article

Abstract: In cutting processes, tool condition affects the quality of the manufactured parts. As such, an essential component to prevent unplanned downtime and to assure machining quality is having information about the state of the cutting tool. The primary function of it is to alert the operator that the tool has reached or is reaching a level of wear beyond which behaviour is unreliable. In this paper, the tool condition is being monitored by analysing the electric current on the main spindle via an artificial intelligence model utilising an LSTM neural network. In the current study, the tool is monitored while working on a cylindrical raw piece made of AA6013 aluminium alloy with a custom polycrystalline diamond tool for the purposes of monitoring the wear of these tools. Spindle current characteristics were obtained using external measuring equipment to not influence the operation of the machine included in a larger production line. As a novel approach, an artificial intelligence model based on an LSTM neural network is utilised for the analysis of the spindle current obtained during a manufacturing cycle and assessing the tool wear range in real time. The neural network was designed and trained to notice significant characteristics of the captured current signal. The conducted research serves as a proof of concept for the use of an LSTM neural network-based model as a method of monitoring the condition of cutting tools.
Keywords: tool condition monitoring, artificial intelligence, LSTM neural network
Published in DKUM: 22.04.2024; Views: 147; Downloads: 10
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2.
Načrtovanje tračnega transporterja za sortiranje vijačnih spon za jekleno ločno podporje z uporabo tehnologije strojnega vida : diplomsko delo
David Šiljeg, 2024, undergraduate thesis

Abstract: V premogovniku Velenje uporabljajo vijačne spone za spojitev lokov jeklenega ločnega podporja. V diplomskem delu smo izvedli analitični preračun tračnega transporterja, ki je podpora procesu sortiranja vijačnih spon. Za učinkovito sortiranje objemk in veznic vijačnih spon smo proučili možnost vpeljave sistema strojnega vida. V programskem okolju Matlab smo analizirali posnetke veznic in objemk ter izdelali dva algoritma za sortiranje objemk in veznic vijačnih spon. Sistem strojnega vida za sortiranje objemk je bil 90 % učinkovit, medtem ko je sistem za sortiranje veznic dosegel 100 % učinkovitost.
Keywords: tračni transporter, strojni vid, Matlab, vijačne spone, sortiranje
Published in DKUM: 12.04.2024; Views: 199; Downloads: 34
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3.
Optimization of chaboche material parameters with a genetic algorithm
Nejc Dvoršek, Iztok Stopeinig, Simon Klančnik, 2023, original scientific article

Keywords: Chaboche material model, parameter optimization, genetic algorithm, finite element method
Published in DKUM: 04.04.2024; Views: 129; Downloads: 9
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4.
Prediction of the form of a hardened metal workpiece during the straightening process
Tadej Peršak, Jernej Hernavs, Tomaž Vuherer, Aleš Belšak, Simon Klančnik, 2023, original scientific article

Abstract: In industry, metal workpieces are often heat-treated to improve their mechanical properties, which leads to unwanted deformations and changes in their geometry. Due to their high hardness (60 HRC or more), conventional bending and rolling straightening approaches are not effective, as a failure of the material occurs. The aim of the research was to develop a predictive model that predicts the change in the form of a hardened workpiece as a function of the arbitrary set of strikes that deform the surface plastically. A large-scale laboratory experiment was carried out in which a database of 3063 samples was prepared, based on the controlled application of plastic deformations on the surface of the workpiece and high-resolution capture of the workpiece geometry. The different types of input data, describing, on the one hand, the performed plastic surface deformations on the workpieces, and on the other hand the point cloud of the workpiece geometry, were combined appropriately into a form that is a suitable input for a U-Net convolutional neural network. The U-Net model’s performance was investigated using three statistical indicators. These indicators were: relative absolute error (RAE), root mean squared error (RMSE), and relative squared error (RSE). The results showed that the model had excellent prediction performance, with the mean values of RMSE less than 0.013, RAE less than 0.05, and RSE less than 0.004 on test data. Based on the results, we concluded that the proposed model could be a useful tool for designing an optimal straightening strategy for high-hardness metal workpieces. Our results will open the doors to implementing digital sustainability techniques, since more efficient handling will result in fewer subsequent heat treatments and shorter handling times. An important goal of digital sustainability is to reduce electricity consumption in production, which this approach will certainly do.
Keywords: sustraightening process, hardened workpiece, manufacturing, U-Net convolutional neural network, modeling, point cloud, digital sustainability
Published in DKUM: 02.04.2024; Views: 215; Downloads: 16
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5.
Razvoj in komercialna uveljavitev vertikalnega stojala za prenosnik : magistrsko delo
Žan Čakš, 2024, master's thesis

Abstract: V magistrskem delu je predstavljena izdelava stojala za prenosni računalnik, ki rešuje tri ključne težave sodobnih prenosnih računalnikov: slaba ergonomija, pregrevanje in prostornost. Pokazali smo, da prenosni računalniki niso ergonomsko primerni za vsakdanjo uporabo, in ponudili rešitev. Zasnovali smo stojalo, ki rešuje problem ergonomije prenosnikov, in z raziskavo trga pokazali, da na trgu obstaja vrzel za takšno stojalo, ki jo lahko zapolnimo. Razvili smo poslovni model in predstavili način financiranja prek kampanje množičnega financiranja na Kickstarterju.
Keywords: podjetništvo, ergonomija, prototip, modeliranje, proizvodnja, množično financiranje, poslovni model, stojalo za prenosnik
Published in DKUM: 02.04.2024; Views: 187; Downloads: 21
.pdf Full text (3,57 MB)

6.
Analiza in optimizacija procesnih parametrov sušilnice za koruzo : magistrsko delo
Marko Simonič, 2024, master's thesis

Abstract: Magistrsko delo obsega opis razvoja in implementacije modela globoke nevronske mreže z LSTM arhitekturo. Model omogoča napovedovanje vlažnosti koruze na izhodu iz sušilnega sistema na podlagi meritev vlažnosti koruze na vhodu in beleženja temperaturnih parametrov med obratovanjem. Razvoj modela je vključeval temeljito analizo in preučitev posameznih temperaturnih parametrov. Pri tem smo izvedli regresijsko analizo, ki je raziskovala vpliv vhodne vlažnosti, ciljne temperature gorilnika in časa sušenja med izpusti koruze na spremembe temperaturnih parametrov v sušilnem sistemu. Poleg tega smo preučili tudi statistične vplive samih temperaturnih parametrov na vlažnost koruze na izhodu iz sušilnega sistema. Analiza nam je omogočila ustrezno pripravo podatkov za učenje napovednih modelov. Uspešnost razvitih napovednih modelov je ocenjena s povprečno absolutno napako (angl. mean absolute error – MAE), povprečno kvadratno napako (angl. mean squared error – MSE), korenom povprečne kvadratne napake (angl. root mean squared error – RMSE) in srednjo absolutno odstotkovno napako (angl. mean absolute percentage error – MAPE). Najuspešnejši model za napovedovanje vlažnosti na izhodu iz sušilnega sistema je imel na učnih podatkih odlično zmogljivost napovedovanja, saj so povprečne vrednosti MAE znašale 0,352, RMSE 0,645, MSE 0,416 in MAPE 2,555. Izvedena je bila tudi vizualizacija rezultatov za nadaljnjo analizo in interpretacijo.
Keywords: sušilni sistem, globoko učenje, LSTM, napovedovanje, optimizacija, koruza, vlaga
Published in DKUM: 28.03.2024; Views: 198; Downloads: 41
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7.
Influence of Al2O3 nanoparticles addition in ZA-27 alloy-based nanocomposites and soft computing prediction
Aleksandar Vencl, Petr Svoboda, Simon Klančnik, Adrian But, Miloš Vorkapić, Marta Harničárová, Blaža Stojanović, 2023, original scientific article

Abstract: Three different and very small amounts of alumina (0.2, 0.3 and 0.5 wt. %) in two sizes (approx. 25 and 100 nm) were used to enhance the wear characteristics of ZA-27 alloy-based nanocomposites. Production was realised through mechanical alloying in pre-processing and compocasting processes. Wear tests were under lubricated sliding conditions on a block-on-disc tribometer, at two sliding speeds (0.25 and 1 m/s), two normal loads (40 and 100 N) and a sliding distance of 1000 m. Experimental results were analysed by applying the response surface methodology (RSM) and a suitable mathematical model for the wear rate of tested nanocomposites was developed. Appropriate wear maps were constructed and the wear mechanism is discussed in this paper. The accuracy of the prediction was evaluated with the use of an artificial neural network (ANN). The architecture of the used ANN was 4-5-1 and the obtained overall regression coefficient was 0.98729. The comparison of the predicting methods showed that ANN is more efficient in predicting wear.
Keywords: ZA-27 alloy, Al2O3 nanoparticles, nanocomposites, wear, response surface methodology, artificial neural network
Published in DKUM: 20.03.2024; Views: 196; Downloads: 6
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8.
Analiza konkurentov in ponudnikov panelnih ograj : diplomsko delo
Luka Zadnik, 2022, undergraduate thesis

Abstract: Vse več ljudi se odloča za ograditev svoje lastnine oziroma objekta, bodisi zaradi varnosti ali ureditve okolice. V diplomskem delu je prikazana analiza večjih podjetij, ki se ukvarjajo z distribucijo panelnih ograj na slovenskem tržišču. Podjetja smo analizirali glede na marketinške poti, promocijo in ceno izdelka. V zaključku dela je prikazan pregled trga.
Keywords: panelna ograja, analiza, trg, konkurenti
Published in DKUM: 05.03.2024; Views: 306; Downloads: 24
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9.
Izdelava in obdelava izvrtin : diplomsko delo
Tim Krebs, 2022, undergraduate thesis

Abstract: V diplomskem delu so predstavljeni postopki izdelave izvrtin z vrtanjem in globokim vrtanjem ter njihovo obdelavo s pomočjo grezenja, povrtavanja in rezanja navojev. Predstavljena so ročna in strojna orodja posameznih obdelav ter visokohitrostna obdelava, načini vpenjanja orodij in obdelovancev, vrste hladilno mazalnih tekočin in vrste vrtalnih strojev. V praktičnem preizkusu diplomskega dela je raziskano, kolikšno je odstopanje premera izvrtine od nazivne vrednosti premera svedra pri materialih treh različnih trdnosti.
Keywords: vrtanje, grezenje, povrtavanje, rezanje navojev, hladilno mazalne tekočine
Published in DKUM: 05.03.2024; Views: 257; Downloads: 18
.pdf Full text (2,11 MB)

10.
Določanje razdalje do predmeta s pomočjo strojnega vida : diplomsko delo
Matic Krepek, 2023, undergraduate thesis

Abstract: V diplomskem delu je predstavljena uporaba strojnega vida za merjenje razdalje med opazovanim objektom in kamero, s čimer se definira tri prostostne stopnje, ki opišejo položaj predmeta v prostoru oz. njegovo pozicijo. Za popolno definiranje predmeta v prostoru je poleg njegove pozicije potrebna še orientacija, ki je v obravnavanem delu poenostavljena in vnaprej znana. V tem primeru zaznava globine zadostuje za robotsko manipulacijo predmeta. Cilj diplomskega dela je izdelava sistema 3D strojnega vida s kar se da natančno zaznavo razdalje do predmeta. Predstavljena sta dva različna pristopa. Prvi pristop je z uporabo ene kamere in na podlagi eksperimenta ugotoviti funkcijo globine v odvisnosti od površine predmeta na zajeti sliki ter v oddaljenosti središča predmeta od središča zajete slike. Drugi pristop je z dvema kamerama in tako imenovanim stereo vidom, s katerim lahko s pomočjo dveh zajetih slik z dveh različnih vnaprej znanih zornih kotov pridobimo 3D informacije o predmetu. V namen zajema in obdelave slik je bil uporabljen programski paket MATLAB. Uporabljeni sta bili dve spletni kameri Logitech “C920 HD PRO”, ki sta bili vpeti v ohišje, slednje pa je bilo pritrjeno na stojalo. Razdalja med kamerama in objektom se je tekom izvajanja eksperimenta spreminjala. V diplomskem delu so predstavljeni rezultati testiranj obeh razvitih pristopov.
Keywords: strojni vid, stereo vid, zaznavanje globine, kamera, MATLAB
Published in DKUM: 04.03.2024; Views: 218; Downloads: 12
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