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V nalogi obravnavamo vpliv tehnologije 3D tiskanja termoplastičnih kompozitov, ojačanih z dolgimi enosmernimi steklenimi vlakni na natezno in upogibno trdnost, ter primerjamo rezultate, dobljene z eksperimentalnim testiranjem in numeričnim simuliranjem. V prvem delu naloge smo analizirali materialne lastnosti osnovnega materiala in vlaken. Določili smo materialne parametre in izračunali elastične parametre za popis ortotropnih lastnosti ojačitvenih vlaken s semiempiričnim Chamijevim modelom. Zatem smo določili geometrijo testnih preizkušancev, kjer smo opazovali vpliv tiskane smeri, in geometrijo kompozitnih preizkušancev, pri katerih smo upoštevali izmenično in zgoščeno razporeditev ojačitev po prerezu. Nastale natisnjene preizkušance smo obremenjevali na nateg in upogib ter opazovali njihov odziv. Dobljene rezultate smo primerjali z rezultati numeričnih simulacij, kjer smo vrednotili ojačitve z metodo membran, metodo nosilcev in metodo kompozitne postavitve. S primerjavo rezultatov smo ugotovili, da ima tehnologija 3D tiskanja velik vpliv na končno trdnost kompozita, kjer zaradi šibkega stika med matrico in vlaknom prihaja do razslojevanja. We investigate the impact of 3D printing technology of thermoplastic composites reinforced with long unidirectional glass fibers on the tensile and bending strength, where we compare the results obtained by experimental testing and numerical simulation. In the first part of the assignment, we analysed the material properties of the base material and fibers. We determined the material parameters and calculated the elastic parameters for orthotropic properties of the reinforcing fibers using the semi-empirical Chamis model. After that, we determined the geometry of the test specimens, where we observed the influence of the printed direction, and the geometry of the composite specimens, where we considered the alternating and condensed distribution of reinforcements across the cross-section. The resulting printed test pieces were subjected to tension and bending, and their response was observed. The obtained results were compared with the results of numerical simulations, where reinforcements were evaluated using the membrane method, the beam method and the composite layout method. By comparing the results, we found that the 3D printing technology has a great influence on the final strength of the composite, where delamination occurs due to the weak contact between the matrix and the fiber.

V delu je predstavljena uporaba 3D tiskanega metamateriala za namen nizkofrekvenčne vibroizolacije v strukturni dinamiki. Osnovna reprezentativna celica metamateriala, ki jo tvorita resonator in struktura nelinearne togosti, izkazuje visoko statično in nizko dinamično togost. Tako imenovana kvazi ničelna togost omogoča pojav pasovne vrzeli pri zelo nizkih frekvencah. Preko obravnavane osnovne reprezentativne celice, katere periodična razporeditev tvori metamaterial, določimo lastnosti neskončno dolgega metamateriala z analitično izpeljavo disperzijskih krivulj. Termoaktivne lastnosti uporabljenega prevodnega filamenta omogočajo adaptivno krmiljenje togosti in prilagajanje pasovne vrzeli preko segrevanja z Joulovim tokom. Numerične simulacije prenosnosti končnega števila celic potrjujejo pasovne vrzeli pri enakih frekvencah kot disperzijske krivulje. Končni metamaterial in eksperimentalna prenosnost kažeta obstoj pasovnih vrzeli, ki so zmožne znižati prenosnost tudi za 30 do 40 dB, vendar se te zaradi lezenja materiala nahajajo pri višjih frekvencah, kot napoveduje teorija. This thesis presents the use of 3D printed metamaterials for low-frequency vibration isolation in structural dynamics. The basic representative cell of the metamaterial consists of a resonator and a structure with nonlinear stiffness, exhibiting high static and low dynamic stiffness. The so-called quasi-zero stiffness enables the appearance of band gaps at very low frequencies. Through the considered basic representative cell, whose periodic arrangement forms the metamaterial, the properties of an infinitely long metamaterial are determined by analytically deriving dispersion curves. The thermoactive properties of the used conductive filament allow for adaptive stiffness control and adaptation of the band gap through Joule heating. Numerical simulations of the transmission of a finite chain of cells confirm the existence of band gaps at the same frequencies as the dispersion curves. The final metamaterial and experimental transmission show the existence of band gaps capable of reducing transmission by 30 to 40 dB, but these are located at higher frequencies than predicted by theory due to material creep.

In this study, 3D-printed connectors to replace the typical L-shaped joints in the construction of a chair were developed, tested and numerically analysed. Different connectors were designed and manufactured with a fused deposition modelling (FDM) 3D printer using acrylonitrile butadiene styrene (ABS) with the aim to find a simple shaped connector which could be used to build chairs and withstand standard chair loading requirements. The strength and stiffness of the joints were tested and compared with traditional beech mortise-and-tenon joints. Numerical stress and strain analyses were performed with the finite element method for an orthotropic linear-elastic model. The experimental results showed that joints with 3D-printed connectors achieved lower strength than the traditional wooden mortise-and-tenon joints with similar dimensions. The results indicate that the effect of reinforcement of the connector were not recognised due to the small thickness and inadequate geometric position and arrangement of the reinforcement ABS material. The chair assembled with 3D-printed connectors could withstand the loads for seating, but failed the backrest test according to standard EN 1728:2002. The connectors need to be optimised and reinforced to withstand standard loads. Nasl. z nasl. zaslona. Opis vira z dne 18. 6. 2022. Bibliografija.

V sklopu magistrske naloge smo raziskali kako vzdrževanje konstantne temperature v delovnem območju 3D tiskanja vpliva na kakovost izdelkov iz zahtevnejših materialov. V prvi fazi potrebujemo kvalitetno ohišje za 3D tiskalnik. Ohišje omogoča hitrejše ogrevanje delovnega prostora, preprečuje požar, zaščiti tiskalnik in izdelek pred nečistočami iz okolice. Prav tako zmanjša hrup tiskalnika. Nadalje potrebujemo grelec za dodatno ogrevanje prostora, ko je to potrebno. Izziv je zagotavljanje optimalne temperature in nizke vlažnost zraka v delovnem prostoru tiskalnika. V ta namen smo zasnovali modul, ki bo nenehno nadzoroval in krmilil ti dve veličini. S tem bomo povečali kakovost izdelkov oziroma zagotovili boljše pogoje za izdelavo. V sklopu metodologije predstavimo zasnovo različnih konceptov, preračune in simulacije, ki jih tudi eksperimentalno preverimo. Na podlagi kriterijev izberemo najustreznejši koncept in ga v naslednji fazi izdelamo. Opišemo postopek priprave sistema za programiranje mikrokrmilnika Arduino in elektro vezav posameznih komponent. Ob pomoči modula za krmiljenje temperature, ohišja in IR grelca smo v območju delovnega prostora tiskalnika zagotovili konstantno temperature v območju 1 °C ter nizko vlažnost, ki znaša okoli 20 %. Kakovost tiskanja zahtevnejših se je po pričakovanjih izboljšala. As part of the MSc thesis, we investigated how maintaining a constant temperature in the 3D printing working area affects the quality of products made from more complex materials. In the first phase, we need a quality housing for the 3D printer. The enclosure allows for faster heating of the work area, prevents fire, protects the printer and the product from impurities from the surroundings. It also reduces the noise of the printer. Furthermore, we need a heater for additional heating of the room when needed. The challenge is to ensure optimum temperature and low humidity in the printer's workspace. To this end, we have designed a module that will continuously monitor and control these two variables. This will increase the quality of the products or ensure better production conditions. As part of the methodology, we present the design of various concepts, calculations and simulations, which are also experimentally verified. Based on the criteria, we select the most appropriate concept and produce it in the next phase. We describe the process of preparing the system for programming the Arduino microcontroller and the electrical connections of the individual components. With the help of the temperature control module, the housing and the IR heater, we have ensured a constant temperature in the range of 1 °C and a low humidity of around 20 % in the working area of the printer. As expected, the print quality of the more demanding prints has improved.

Za izdelavo funkcionalnih senzoričnih sistemov potrebujemo materiale s tremi različnimi lastnostmi, to so strukturni, senzorični in prevodni materiali. Strukturni material je neprevodni polimer, ki senzoričnemu sistemu nudi trdnost in togost. Senzorni material je običajno material na osnovi ogljika, kot so na primer grafen, saje in ogljikove nanocevke. Prevodni material pogosto predstavlja največji izziv. Pri prenosu signala lahko njegova upornost povzroča zamik, šum ali pregrevanje elementov, posledica tega je lahko velika merilna napaka ali nedelovanje sistema. V diplomski nalogi smo se osredotočili na visoko prevodne kompozitne filamente za 3D tisk na polimerni osnovi s kovinskimi delci. Opredelili smo njihove mehanske lastnosti, poleg tega pa smo opredelili tudi mehanizme, ki vplivajo na vzpostavitev geometrijskega in prevodnega omrežja. V eksperimentalnem delu so prikazani rezultati, ki potrjujejo, da je mogoče z dodajanjem kovinskega polnila v polimerno matrico vzpostaviti prevodno omrežje znotraj kompozita in pri tem obdržati ugodne mehanske lastnosti polimera. To create functional sensor systems, we need materials with three distinct properties: a structural material, a sensoric material and a conductive material. The structural material is a non-conductive polymer which provides rigidity, stiffness and solidity to sensor system. The sensoric material is usually based on carbon in forms of graphene, soot or carbon nano-tubes. The conductive material is often the biggest challenge. When transmitting the signal, its resistance can cause noise, delay or overheating of elements which can result in large measurement errors or system failure. The thesis will focus on highly conductive polymer composite filaments for 3D printing which are based on polymer matrix with metal particles. The mechanical properties of such composites and mechanisms that affect the establishment of a geometric and conductive mesh will be defined. Results in the experimental part of this thesis will confirm that it is possible to add metal particles to a polymer material in order to form a conductive mesh without losing the favorable mechanical properties of the polymer.

Cilj ovog rada bio je ispitati mogućnost primjene 3D ispisa u proizvodnji funkcionalnog proizvoda na bazi jagode (Fragaria x ananassa Duch.). Istraživanje je provedeno ispitujući utjecaj dva različita programa ispisa temeljenih na ekstruziji, uz primjenu dva različita škrobna hidrokoloida (kukuruzni vs. pšenični) u različitim udjelima (10, 15 i 20 %, w/w) na stabilnost bioaktivnih spojeva (ukupni fenoli, hidroksicimetne kiseline, flavonoli, ukupni flavonoidi, antocijani i kondenzirani tanini) i antioksidacijski kapacitet (DPPH i FRAP). Također, određeni su i pH vrijednost te aktivitet vode u svim ispitivanim uzorcima. Vrsta škroba imala je statistički značajan utjecaj na pH i aw vrijednosti, sve određivane bioaktivne spojeve i antioksidacijski kapacitet analiziranih 3D proizvoda. Udio škroba i tip programa ispisa također značajno utječu na većinu određivanih spojeva, a za očuvanje bioaktivnog profila i antioksidacijskog kapaciteta 3D tiskanog proizvoda najboljim se pokazao udio škroba od 15% i uporaba programa 2 za ispis. 3D ispis može se smatrati tehnologijom visokog potencijala za razvoj inovativnih i individualnih funkcionalnih proizvoda.

Potreba po posamezniku prilagojenem odmerjanju zdravila je dobro zavedana pri sodobnem razvoju in uporabi zdravil. 3D-tiskanje je izpostavljeno kot potencialna strategija za revolucijo na področju personalizirane medicine ter izboljšanje njene prilagodljivosti, učinkovitosti, varnosti in uporabnosti. Namen študije je bil optimizirati nov in poenostavljen pristop k tehnologiji 3D tiskanja s ciljnim nalaganjem, z uporabo votlih nosilcev (HF). S pomočjo računalniško podprtega načrtovanja je bil zasnovan 3D model HF, ki je omogočal enostavnejše in mnogo hitrejše polnjenje učinkovine ter, zaradi večjega votlega volumna, tudi višje masne koncentracije v primerjavi z referenčnim modelom. HF, izdelani iz komercialno dostopnih filamentov polimlečne kisline ali hidroksipropilmetil celuloze, so bili napolnjeni z dvema različnima učinkovinama (naproksenom ali indometacinom) in vstavljeni v 3D-tiskalnik. Za uspešno tiskanje z napolnjenimi HF, je bila potrebna prilagoditev hitrosti tiskanja, temperature tiskanja in vrste adhezije na odlagalni mizici 3D tiskalnika. Razlike v parametrih niso bile opazne le pri različnih polimerih, temveč tudi med posameznim polimerom v kombinaciji z različnimi učinkovinami, kar je kazalo na vpliv medsebojnih interakcij komponent na rezultate tiskanja. Primerjave enakomernosti mas in vsebnosti učinkovin med tabletami enakih HF so pokazale, da so kombinacije polimera in učinkovine, s tiskanjem katerih je bilo možno doseči želeno obliko tablet, imele tudi manjšo variacijo mas in bolj enakomerno porazdelitev učinkovine med tabletami. Ugotovljeno je bilo, da je dobro mešanje polimera ključnega pomena za uspeh 3D tiskanja. Napovedi mešanja med različnimi kombinacijami polimerov in učinkovin, pridobljene na podlagi rezultatov 3D tiskanja, so bile ovrednotene z uporabo Hansenovih parametrov topnosti (HSP), metode depresije temperature taljenja (MPD) in nove metode z uporabo entalpije taljenja in mešanja (Hmm). Zaradi fizikalno-kemijskih lastnosti učinkovin in polimerov, ki so vplivale na rezultate analize s Hmm in MPD, je bilo ugotovljeno, da so HSP najbolj koristno orodje za napovedovanje mešanja in razlago rezultatov za te specifične kombinacije učinkovin in polimerov. The need for patient-tailored drug dosage development has been well recognized in current medication development and usage. 3D printing is highlighted as a potential strategy to revolutionize the personalized medicine field and improve its flexibility, efficiency, safety, and utility. This study aimed to optimize a new and simplified approach to the Fused Deposition Modeling 3D printing technique using hollow filaments (HFs). Computer-aided design of the HF was successfully developed, allowing faster drug loading and, due to the higher filling capacity, higher mass concentrations of the drug compared to the reference model. HFs, printed from commercially available Polylactic acid and Hydroxypropyl Methylcellulose filaments, respectively, were filled with two different drugs (Naproxen or Indomethacin) and fed into the 3D printer. Printing speed, printing temperature, and the adhesion type on the build plate had to be adjusted to successfully achieve the printability of drug-loaded HFs. Not only was the difference in parameters noticeable for different polymers, but also within each polymer with different drugs, indicating the specific drug-polymer interplay had a significant impact on printing outcomes. The mass and dose homogeneity studies between tablets of the same HF showed, that the combinations of the drug and polymer, showing the best miscibility with lower dose variation, in general, had better reproducibility and printability of tablets. The finding suggested that the drug's and polymer's miscibility is crucial in 3D printing success. Predictions of miscibility between different drug-polymer systems, obtained from 3D printing results, were evaluated using Hansen Solubility Parameters (HSPs) method, The Melting Point Depression (MPD) method, and the novel method utilizing The Enthalpy of Melting and Mixing (Hmm). Due to the physicochemical properties of drug-polymer systems that might have affected the analysis outcome of Hmm and MPD, HSPs were found to be the most helpful tool to predict miscibility and explain results acquired from the conducted experiments for these specific drug-polymer systems.

Posije mogu obogatiti snack proizvode prehrambenim vlaknima, ali pri tome negativno utječu na tehnološka i senzorska svojstva proizvoda. Cilj ovoga rada je bio odrediti utjecaj fermentacije posija pšenice i amaranta na reološka, fizikalna i senzorska svojstva 3D tiskanih snackova. Fermentacija je provedena koristeći pekarski kvasac (Saccharomyces cerevisiae) samostalno ili u kombinaciji sa LV1 starterom, Limosilactobacillus fermentum, Kluyveromyces marxianus ili inulinazom. Određeni su reologija tijesta, preciznost tiska, točnost oblika i deformacija tijekom pečenja, boja, tekstura i senzorska svojstva pečenih 3D snackova. Fermentacija je utjecala na povećanje vrijednosti kompleksne viskoznosti i naprezanja na granici razvlačenja, bolju prezicnost tiska, manju deformaciju tijekom pečenja i manju tvrdoću snackova. Intenzitet pojedinih senzorskih svojstava je ovisio o vrsti posija i načinu fermentacije, a rezultati hedonističke senzorske analize su bili slični između uzoraka sa pšeničnim i posijama amaranta. Bran can enrich snacks with dietary fiber, but it has a negative technological effect on the production process and on the sensory characteristics of the final product. The aim of this study was to investigate the impact of bioprocessing of wheat and amaranth bran on rheological, physical and sensory characteristics of 3D printed snacks. Bran was bioprocessed with Saccharomyces cerevisiae alone or combined with commercial starter LV1, Limosilactobacillus fermentum, yeast Kluyveromyces marxianus, or inulinase. Dough rheology, printing precision, shape accuracy, shrinkage in baking, colour, texture and sensory characteristics were determined. Bioprocessing of the bran resulted in higher complex viscosity and yield stress values, better printing precision, less shrinkage during baking and softer snacks. The intensity of sensory characteristics depended on the bran type and bioprocessing agent but hedonistic analysis results were similar between snacks with wheat and amaranth bran.

Zadnja leta tehnologija 3D tiskanja doživlja velik razvoj na področju živilske industrije, predvsem slaščičarstva. Tehnologija 3D omogoča tiskanje prilagojenih oblik in vzorcev, pripomore k personalizirani prehrani in tudi znižuje količino odpadkov. V delu smo najprej predstavili osnovno delovanje in različne tehnologije 3D tiskanja, ki se uporabljajo v živilskem sektorju. V nadaljevanju smo preučili primerne materiale za 3D tiskanje slaščic in njihove lastnosti, ki vplivajo na kakovost samega tiska. Predstavili smo tudi nekaj tiskalnikov na trgu slaščičarstva ter bolj podrobno opisali tiskalnik Foodini, s katerim smo natisnili nekaj izdelkov iz sladkorja in s tem spoznali možne zaplete med tiskom. Tehnologija 3D tiskanja ima tudi pozitiven ekološki vpliv, saj zaradi povečanja izkoristka surovin nastaja manj odpadkov. S skrajšanjem časa tiskanja, povečanjem možnosti izbire materialov in znižanjem stroškov bo tehnologija v prihodnosti lahko konkurirala tradicionalni proizvodnji živil. In recent years, 3D printing technology has seen great development in the food industry, especially in the confectionery industry. It enables the printing of customized shapes and patterns, contributes to personalized nutrition, and also reduces the amount of waste. In the work, we first introduced the basic operation and various 3D printing technologies used in the food industry. As part of the project, we investigated suitable materials for confectionery 3D printing and their properties that affect the quality of the print itself. We also presented some printers on the confectionery market and took a closer look at the Foodini printer, which we also used to print some shapes from sugar, learning about possible complications in printing. This technology would also have a positive impact on the environment, as less waste would be generated through the increased use of raw materials. By improving printing times, offering a wider choice of materials and reducing costs, the technology could compete with traditional food production in the future.

Tema predstavljene diplomska naloge je kontrolo polimernih zobnikov z uporabo 3D skeniranja. Obravnavan zobnik je bil izdelan s 3D tiskom in kasneje skeniran z obtičim skenerjem. Pridobljena trikotna mreža zobnikov je bila analizirana s programom, ki je bil razvit v laboratoriju LeCAD, za namen kontrole zobnikov. Končni rezultat vrednotenja je pokazal, da je metoda primerna za kontrolo zobnikov. Največjo napako končnim rezultatom je prispevala metoda izdelave zobnikov. The topic of the presented thesis is the control of polymer gears using 3D scanning. The gear in question was produced with 3D printing and later scanned with a 3D scanner. The obtained triangular mesh of gears was analyzed with a program developed in the LeCAD laboratory for the purpose of gear control. The final result of the analyzes showed that the method is suitable for gear control. The most significant error in the final results was contributed by the manufacturing method of the gears.

Orodno jeklo za delo v vročem H13 je visokokakovostno in v inženirski praksi pogosto uporabljeno jeklo. V diplomskem delu smo obravnavali njegovo različico izdelano z aditivno tehnologijo t.i. 3D tiska kovinskih materialov. V okviru eksperimentalnega dela smo izvedli meritve toplotne prevodnosti in specifične toplote ter določili temperaturno prevodnost pri sobni temperaturi jekla izdelanega z aditivno tehnologijo in jih primerjali z vrednostmi za jeklo izdelano po klasični proceduri. Meritve, vrednotenje in analizo smo izvedli na napravi za določanje toplotnih lastnosti Hot Disk TPS 2200 v skladu s standardom ISO 22007-2. Vrednosti toplotnih lastnosti jekla H13 izdelanega po klasični metodi znašajo: toplotna prevodnost 26,81 W?m-1?K-1, specifična toplota 3,73 MJ?m-3?K-1 in temperaturna prevodnost 7,19 mm2?s-1. Vrednosti toplotnih lastnosti jekla za delo v vročem H13 izdelanega s 3D tiskom pa so: Prvi poizkus: toplotna prevodnost 18,16 W?m-1?K-1, specifična toplota 3,57 MJ?m-3?K-1 in temperaturna prevodnost 5,09 mm2?s-1, Drugi poizkus: toplotna prevodnost 18,60 W?m-1?K-1, specifična toplota 3,64 MJ?m-3?K-1 in temperaturna prevodnost 5,11 mm2?s-1. Ugotovili smo, da so toplotne lastnosti jekla H13 izdelanega z 3D tiskom manjše od jekla H13 izdelano po klasični metodi: toplotna prevodnost manjša za 8,21 W?m-1?K-1, specifična toplota manjša za 0,09 MJ?m-3?K-1in temperaturna prevodnost manjša za 2,08 mm2?s-1. Sklepamo, da je glavni razlog prisotnost zračnih mehurčkov oziroma por v vzorcu. Hot tool steel H13 is a high-quality and widely used steel in engineering practice. In the thesis, we discussed its version made with additive technology, the so-called 3D printing of metal materials. As part of the experimental work, we performed measurements of thermal conductivity and specific heat and determined the temperature diffusivity at room temperature of steel produced with additive technology and compared them with the values for steel produced according to the classical procedure. Measurements, evaluation and analysis were performed on the Hot Disk TPS 2200 device for determining thermal properties in accordance with the ISO 22007-2 standard. The values of the thermal properties of H13 steel produced by the classic method are: thermal conductivity 26.81 W⠙m-1⠙K-1, specific heat 3.73 MJ⠙m-3⠙K-1 and temperature diffusivity 7.19 mm2⠙s-1. The values of the thermal properties of the H13 hot work steel produced with 3D printing are: First test: thermal conductivity 18.16 W⠙m-1⠙K-1, specific heat 3.57 MJ⠙m-3⠙K-1and temperature diffusivity 5.09 mm2⠙s-1, Second test: thermal conductivity 18.60 W⠙m-1⠙K-1, specific heat 3.64 MJ⠙m-3⠙K-1 and temperature diffusivity 5.11 mm2⠙s-1. We found that the thermal properties of H13 steel produced by 3D printing are lower than H13 steel produced by the classical method: thermal conductivity lower by 8.21 W⠙m-1⠙K-1, specific heat lower by 0.09 MJ⠙m-3⠙K-1 and temperature diffusivity smaller by 2.08 mm2⠙s-1. We conclude that the main reason is the presence of air bubbles or pores in the sample.

The additive technologies widely used in recent years provide enormous flexibility in the production of cellular structures. Material extrusion (MEX) technology has become very popular due to the increasing availability of relatively inexpensive desktop 3D printers and the capability of fabricating parts with complex geometries. Poly-lactic acid (PLA) is a biodegradable and commonly applied thermoplastic material in additive manufacturing (AM). In this study, using a simulation method based on the user subroutine titled “user subroutine to redefine field variables at a material point” (USDFLD) in the finite element method (FEM) ABAQUS software, the elastic stiffness (ES) of a cylindrical lightweight cellular PLA sample with a 2.4 mm infill line distance (ILD), which was designed as a layered structure similar to the laboratory mode with a MEX method and was subjected to cyclic compressive loading, was investigated by considering the variation of the Young’s modulus depending on the variation of the equivalent plastic strain (PEEQ). It was observed that the PLA sample’s elastic stiffness increases during cyclic loading. This increase is high in the initial cycles and less in the subsequent cycles. It was also observed that the simulation results are in good agreement with the experimental results.

The double-weave structure of a fabric allows for the use of different materials and weave structures for the upper and lower layer, which can be advantageous in the functionalization of 3D printed textiles. Therefore, the aim of this research was to investigate the influence of simple and double-weave structures on the adhesion of 3D printed fabrics. From this perspective, we investigated the influence of different twill derivates and weft densities on the adhesion force. We produced fabrics specifically for this study and printed them with a polylactic acid filament using Fused Deposition Modeling technology. The T-peel test was performed to measure the adhesion, and the results were statistically analyzed. A morphological study of the surfaces and cross-sections of the 3D printed fabrics helped us interpret the results. We found that adhesion was higher for double fabrics when printed with a smaller z-distance, where the molten polymer reached the lower layer of the fabric and adhered to it. The opposite was confirmed when printing with a larger z-distance, where adhesion was higher for simple fabrics. Both weave and density had a significant effect on adhesion in all cases. Surprisingly, different twill derivatives generally had a greater influence on adhesion than density.

Trirazsežno tiskanje je področje novih tehnologij, ki omogoča pripravo personaliziranih enoenotnih trdnih farmacevtskih oblik z dograjevanjem po plasteh. Po odobritvi prvega 3D tiskanega zdravila Spritam s strani FDA, je tehnologija 3D tiskanja postala predmet precejšnjega zanimanja med raziskovalci. V magistrski nalogi smo se osredotočili na praškovno-brizgalno tehnologijo tiskanja tablet. Pri tej tehnologiji se trdne farmacevtske oblike gradijo z dodajanjem praškastega materiala v plasteh, ki jih poveže vezivna tekočina, ki jo s pomočjo šob tiskalnika nanašamo v obliki drobnih kapljic na vsako novo nanešeno plast prahu. Načrt za tablete izdelamo v računalniškem programu, kamor vnesemo dimenzije in obliko tablet ter procesne parametre tiskanja. S praškovno-brizgalno tehnologijo smo izdelovali tablete s pomočjo namensko razvitega 3D tiskalnika PicoJet. V prvem delu magistrske naloge smo pripravili tri procesibilne vezivne tekočine in zasnovali ustrezno zmes praškov. Vezivna tekočina je bila sestavljena iz različnih razmerij vode in etanola. Pri zasnovi vezivne tekočine smo upoštevali, da so za uspešno nanašanje vezivne tekočine pomembne: gostota, površinska napetost ter viskoznost tekočine. Končno zmes praškov za tiskanje je sestavljala modelna učinkovina ketoprofen, vodotopni polnili laktoza in manitol, vezivo polivinilpirolidon K25 in drsilo Syloid 244 FP za boljšo pretočnost. Pretočnost praškovne zmesi ima pomembno vlogo, saj delci lahko zaostajajo v zalogovniku tiskalnika in se pomanjkljivo nanesejo na delovno površino tiska. V drugem delu smo s pomočjo načrtovanja eksperimentov preučili vpliv procesnih parametrov in sestave vezivne tekočine na mehanske lastnosti izdelanih tablet. Spoznali smo, da imata višina plasti nasutja praškaste zmesi in številčna gostota aktivnih šob tiskalne glave največji vpliv na mehanske lastnosti tablet (trdnost, krušljivost in razpadnost). Nižja kot je višina plasti in višja kot je gostota aktivnih šob, bolj so pripravljene tablete kompaktne. Po drugi strani pa se je izkazalo, da vezivna tekočina nima izrazitega vpliva na mehanske lastnosti. The three-dimensional printing is an area of new technologies that enables a development of personalized drug delivery systems, where compounds are added layer by layer. After the approval of the first 3D printed drug Spritam by the FDA, 3D printing technology became the subject of interest among researchers. In the thesis we focused on the powder bed jetting technology. This technology enables the production of solid dosage forms by adding powdered material in layers, bound together by a binder fluid, which is applied in the form of tiny droplets to each newly applied layer of powder using a printer nozzle. The design of experiments is created with a computer program, in which we define dimensions, tablet shape and printing process parameters. We produced tablets with powder bed jetting technology using the purpose-developed PicoJet 3D printer. In the first part of the thesis, we prepared three processable binder fluids and designed a suitable powder mixture. The binder fluid was composed of water and ethanol in different ratios. During the design of a liquid binder we considered that important parameters for successful application of the liquid binder are: density, surface tension and viscosity of the liquid. The final powder mixture for printing was prepared from the model drug ketoprofen, water-soluble fillers lactose and mannitol, PVP K25 binder and glidant Syloid 244 FP was added for a better flowability. The flowability of the powder mixture plays an important role, as the particles can lag in the storage tank and are consequently poorly applied to the work surface. In the second part, we evaluated the impact of process parameters and binder fluid composition on the mechanical properties of the manufactured tablets with the help of the design of experiments. We determined that the height of the filling layer of the powder mixture and the active nozzle density of the printing head have the greatest impact on the mechanical properties of the tablets (hardness, friability, disintegration). The lower the filling layer height and the higher the active nozzle density, the higher is the compactibility of the produced tablets. On the other hand, we showed that the binder fluid does not have a significant impact on the mechanical properties.

Piezouporovna merilna zaznavala izdelana z metodo 3D tiska prinašajo nove rešitve pri aplikaciji zaznaval v oblikovno strukturo. Električne lastnosti prevodnih polimerov še niso dovolj raziskane, da bi se polimerna piezouporovna zaznavala lahko uporabljala v razširjenem obsegu. Magistrsko delo obsega teoretične osnove piezouporovnih zaznaval in materialov primernih za izdelavo le teh. Opisan je potek merjenja cikličnih obremenitev 3D natisnjenega senzorja upogiba s klasificiranimi premori ter primerjava karakteristik večih preizkušancev med seboj. Piezoresistive sensors made with the 3D printing method bring new solutions in the application of sensors in the design structure. The electrical properties of conductive polymers have not been sufficiently investigated to allow polymer piezoresistive sensors to be used on an extended scale. The master's thesis comprises the theoretical foundations of piezoresistive sensors and materials suitable for their manufacture. The course of measuring the cyclic loads of a 3D printed bending sensor with classified pauses is described, as well as a comparison of the characteristics of several test specimens with each other.

Diplomsko delo zajema analizo vpliva podlage na oprijemljivost materiala pri aditivni izdelavi s postopkom ciljnega nalaganja polimera z uporabo 3D tiskalnika. Uporabljen je bil tiskalnik Creality CR10, ki deluje po FDM metodi. Za analizo oprijemljivosti materiala se je tiskala ploščica pri različnih temperaturah podlage in z uporabo različnih adhezivnih sredstev. Opravljenih je bilo šest različnih tiskov. Najprej se je natisnilo tri ploščice pri treh različnih podlagah brez adhezivnih sredstev, nato pa je sledilo še tiskanje na vseh treh podlagah z uporabo treh različnih adhezivnih sredstev. Analiza ploščic se je opravila pod mikroskopom VHX-6000. Ugotovljeno je bilo, da je ploščica, natisnjena pri temperaturi 70 °C z uporabo adhezivnega sredstva Dimafix, najboljši približek idealnemu tisku. Prav tako je ta ploščica imela najbolj optimalno vizualno oceno in jo je bilo najlažje odstraniti iz grelne plošče po končanem tisku. The diploma thesis includes an analysis of the influence of the substrate on adhesion of the material in additive manufacturing by the process of targeted polymer loading method. A Creality CR10 printer using the FDM method was used. To analyze the adhesion of the material, the plate was printed at different substrate temperatures and with different adhesives. Six different prints were made. First, three tiles were printed on three different substrates without adhesives, then all three substrates were printed with three different adhesives. Analysis of the tiles was performed under a VHX-6000 microscope. It was found that the tile printed with the Dimafix adhesive was the best approximation to the ideal print, also in terms of aesthetics and removal of the tile from the hot plate after printing.

Cilj ovog istraživanja bio je ispitati utjecaj aditivne tehnologije 3D tiskanja na aktivitet vode(aw), pH vrijednost, masene udjele bioaktivnih spojeva, pigmenata i antioksidacijskog kapaciteta (DPPH i FRAP) u 3D tiskanim proizvodima na bazi maginje (Arbutus unedo L.). Analiziran je utjecaj dva različita programa 3D ispisa, kao i vrsta (kukuruzni vs. pšenični) te udio dodanog škrobnog nosača (4, 6 i 8 %). Vrsta škrobnog nosača statistički je značajno utjecala na aw, pH, ukupne fenolne spojeve, hidroksicimetne kiseline, flavonole, monomerne antocijane, kondenzirane tanine, ukupne karotenoide te na antioksidacijsku aktivnost 3D ispisanih uzoraka. Niži udio škrobnog nosača (4 vs. 6 i 8 %) povoljno utječe na stabilnost analiziranih bioaktivnih spojeva, pigmenata te antioksidacijski kapacitet (DPPH). Tip programa 3D ispisa statistički je značajno utjecao na maseni udio flavonola, klorofila a i b, ukupnih karotenoida te na antioksidacijsku aktivnost (FRAP) 3D ispisanih uzoraka. Tehnologija 3D ispisa može se smatrati obećavajućom u sektoru razvoja inovativnih i funkcionalnih proizvoda na bazi maginje. The aim of this study was to investigate the influence of additive 3D printing technology on water activity (aw), pH, mass fraction of of bioactive compounds, pigments, and antioxidant capacity (DPPH and FRAP) in strawberry tree fruit (Arbutus unedo L.) based 3D printed products. The influence of two different 3D printing programs as well as the type (corn vs. wheat) and the percentage of added starch carrier (4, 6 and 8%) were analyzed. The type of starch carrier had a statistically significant effect on aw, pH, total phenolic compounds, hydroxycinnamic acids, flavonols, monomeric anthocyanins, condensed tannins, total carotenoids, and on the antioxidant activity of the 3D-printed samples. The lower percentage of starch carrier (4 vs. 6 and 8%) has a positive effect on the stability of the analyzed bioactive compounds, pigments and antioxidant capacity (DPPH). The type of 3D printing program had a statistically significant effect on the mass fraction of flavonols, chlorophyll a and b, total carotenoids and on the antioxidant activity (FRAP) of the 3D printed samples. 3D printing technology can be considered as promising in the field of development of innovative and functional strawberry tree fruit-based products.

The use of wood particles in wood-plastic composites (WPC) is well known and similar use could occur in materials for fused deposition modeling (FDM) 3D printing. Wood particles could be one of the possible solutions in the search for natural-based materials to minimize the use of synthetic-origin materials in additive manufacturing. Wood particles for 3D printing filaments can be made from wood waste and could serve as a cheap filler or as a value-added reinforcing component, depending on their properties and incorporation. The disadvantages of wood (dimensional changes due to water adsorption and desorption) could be used as functions when dimensional change is desirable, such as in shape-changing 4D printing materials. In this research, FDM printing materials made of polylactic acid (PLA), with different amounts of wood particles, were used to design moisture-induced shape-changing bilayer actuators, which could serve as a principle for active façade or ventilation valves. The initial research shows that the wood content in the WPC causes dimensional changes and thus shape changes of the designed actuators under changing climates. The shape change depends on the ratio of the materials in the two-layered actuator and the wood content in the wood-PLA composite used, and thus on sorption. The rate of the shape change behaves in the same way: the higher the wood content, the greater the change observed. The dynamics of the hygromorphism of bimaterial composites is greater with a small amount of added hygromechanically active material.

V živilskem sektorju ima 3D tiskanje veliko uporabno vrednost. Omogoča tiskanje prilagojenih oblik in modelov, pripomore k personalizirani prehrani, omogoča uporabo prehranskih dopolnil proizvedenih iz odpadne hrane in odvečnih tokov živilske industrije. Rastlinski odpadki so lahko vir dragocenih snovi. Netoksične naravne spojine z antioksidativnim delovanjem v odpadni hrani so pritegnile veliko pozornost, saj je vse bolj jasna neposredna povezava med prehrano, bogato z antioksidanti, in zdravjem. V eksperimentalnem delu naloge smo ugotavljali, kako dodatek čebulnega prahu in spiruline (kot naravnih antioksidantov) v 3D tiskanem živilu vpliva na vsebnost vlage, teksturo, parametre barve in senzorične lastnosti po pripravi in med shranjevanjem piškotov. Rezultati so pokazali, da smo v primeru dodatkov dobili boljše lastnosti končnega izdelka (razen pri senzorični oceni). Z meritvami nismo uspeli potrditi, da dodatek funkcionalnega živila z antioksidativnim učinkom pozitivno vpliva na obstojnost živila. Ob dodatku funkcionalnega živila so se senzorične lastnosti spremenile. Bistveno se je spremenila barva, na druge senzorične lastnosti pa je imela večji vpliv vrsta moke, kot pa sam funkcionalni dodatek. In food sector 3d printing has a big usable value. It enables the printing of customized shapes and models, contributes to a personalised diet, enables the use of food supplements from food waste and excess streams of the food industry. Plant waste can be a source of valuable substances. Non-toxic natural compounds with antioxidant activity in food waste have attracted a lot of attention as there is an increasingly clear direct link between a diet rich in antioxidants and health.. During the experimental work we found out how the addition of onion powder and spiruline (as natural antioxidants) to a 3D printed food affects moisture content, texture, color parameters and sensory properties after preparation and during biscuit storage. The results showed that in the case of added additives, we got better properties of the finished product (except for sensory evaluation). We were unable to confirm by measurements that the addition of a functional food with an antioxidant effect has a positive effect on the persistence of the food. With the addition of a functional food, the sensory properties changed. The colour changed significantly, and other sensory properties had a greater impact on the type of flour than the functional additive itself.

3D tisk omogoča relativno hitro izdelavo prototipov kompleksnih oblik. Kot prva aditivna tehnologija se je uveljavila stereolitografska tehnologija 3D tiska. Pri tem načinu izpostavimo fotopolimer UV svetlobi in ga tako na izpostavljenih mestih strdimo. Plasti se nalagajo ena na drugo in tako na izdelovalni mizici nastane izdelek. V zaključni nalogi smo se posvetili problemu vpliva temperature na reakcijo fotopolimerizacije. V prvem delu smo pregledali literaturo in predstavili aditivne tehnologije ter kakšen vpliv ima na končni izdelek temperatura, pri kateri tiskamo. Na podlagi ugotovljenih dejstev smo izbrali ustrezen način krmiljenja temperature ter komponente, ki bodo uporabljene v krmilnem sistemu. Sistem smo preizkusili v kadi tiskalnika polni vode. Med preizkusi smo merili temperaturo vode in PWM signal mikrokrmilnika. Na podlagi meritev smo optimizirali koeficiente PID krmiljenja. 3D printing enables relatively fast prototyping of complex shapes. Stereolithographic 3D printing technology was the first additive technology. This technology uses UV light to harden photopolymer in desired spots. The layers are stacked on top of each other, creating a part on the production table. In the final thesis, we focused on the problem of the influence of temperature on the photopolymerization reaction. In the first part, we reviewed the literature and presented additive technologies and what effect has the temperature at which we print on the final product. Based on the established facts, we selected the appropriate method of temperature control and the components that will be used in the control system. We tested the system in a printer vat full of water. During the tests, we measured the water temperature and the PWM signal of the microcontroller. Based on the measurements, we optimized the PID control coefficients.

Trenutne oblike magnetnih materialov za elektromotorje so zelo enostavne zaradi tehničnih in ekonomskih razlogov. Tehnologije dodajalnih procesov, med njimi tudi 3D tiskanje, pomenijo korak k novejšim, bolj naprednim oblikam elektromotorjev. Za to nalogo moramo imeti ustrezen magnetni material, ki odgovarja izbranim parametrom obratovanja. Tak material nato z ustrezno tehniko 3D tiska pretvorimo v trajni magnet v poljubnih dimenzijah ali oblikah, ki jih je z ustaljenimi metodami zelo težko izdelati ter ob tem ne pridelamo veliko odpadkov. Za uspešno vpeljavo 3D procesov v industrijo morajo tridimenzionalno natisnjeni izdelki konkurirati konvencionalno proizvedenim. Za ustrezno primerjavo sem iz dosedanjih študij 3D tiska izbral najbolj obetavne in jih primerjal z obstoječimi po času in natančnosti izdelave, fizikalnih in mehaničnih lastnostih magnetov ter magnetnih lastnostih. Za zaključek sem poskusil napovedati, če se bodo tehnologije 3D tiska uspešno integrirale v industrijo ali pa bodo ostale na nivoju izdelovanja protitopov in modeliranju. For its technical and economic reasons, current designs of magnetic materials for electromotors are fairly simple. Technology of add-on production, involving 3D printing, represents a step towards newer and more advanced electric motor shapes. For that we have to provide a certain type of magnetic material, which is transformed into a permanent magnet via 3D printing, which is capable of creating certain shapes of magnets, nearly impossible to create with conventional methods, and produce next to zero waste. If we want 3D printed permanent magnets to become a part of the industry, three-dimensional products must compete with conventional products. To have an adequate comparison, I compared magnets, made by add-on production with conventional production, by comparing creation time, accuracy, physical, mechanical and magnetic properties. To conclude I tried to predict whether 3D printing technologies will succesfully integrate themselves in the industry or will remain as a prototype and modelling tool.

Uporaba 3D tiskanja postaja priljubljena zaradi hitrega prototipiranja in sposobnosti tiskanja kompleksnih struktur. To omogoča sposobnost tiskanja struktur z različnimi oblikami odlaganja plasti materiala pri različnih gostotah polnila, ki vplivajo na ortotropne mehanske lastnosti in posledično na lastno dinamiko tiskanih struktur, katerih analiza je problem zaključne naloge. Izvedena je bila eksperimentalna analiza izbranih tiskanih struktur, na podlagi katere se je določilo dejanske lastne frekvence preizkušancev. Nato se je preko posodabljanja numeričnega modela določil modul elastičnosti tiskanega materiala. Z znanim modulom elastičnosti materiala je bila opravljena statična numerična analiza in posledično karakterizacija ortotropnih lastnosti tiskanih struktur. S popisanimi lastnostmi je bila izvedena numerična modalna analiza modela preizkušanca, ter na koncu primerjava numeričnih rezultatov modalne analize z rezultati eksperimenta. The use of 3D printing is becoming popular due to rapid prototyping and the ability to print complex structures. This enables the ability to print structures with different infill patterns at different infill densities, which affect orthotropic mechanical properties and consequently the intrinsic dynamics of printed structures, the analysis of which is the problem of the final thesis. An experimental analysis of selected printed structures was performed, on the basis of which the actual natural frequencies of the subjects were determined. The modulus of elasticity of the printed material was then determined by updating the numerical model. With the known modulus of elasticity of the material, a static numerical analysis was conducted and consequently the characterization of the orthotropic properties of printed structures was performed. A numerical modal analysis of the models subject was performed with the described properties, and finally a comparison of the numerical results of the modal analysis with the experimental results.

Delo obravnava topološko optimizacijo okvirja tekmovalnega brezpilotnega zrakoplova. Predstavljen je enoosno obremenjen konstrukcijski element, čigar fizikalni model predstavlja osnovo za izpeljavo vodilne enačbe problema. Ta je nato prevedena v integralsko formulacijo, na podlagi katere je izpeljana enačba končnega elementa. Izdelana je začetna geometrija, znotraj katere je izvedena topološka optimizacija preko metode SIMP. Optimirana geometrija je validirana z numerično trdnostno analizo. Rezultat dela je topološko optimiran in za 3D tisk pripravljen okvir dirkalnega letalnika, katerega masa je manjša od mase komercialnih okvirjev na trgu. The presented work deals with a topological optimization of a racing drone frame. An uniaxially loaded structural element is presented, of which the physical model represents the basis for differential equation derivation. Equation is then translated into variational formulation, on the basis of which the finite element equation is derived. The initial geometry is made, within which the topological optimization is performed via SIMP method. The optimized geometry is validated with numerical static structural analysis. The result of the work is a topologically optimized and 3D printing ready racing drone frame, the mass of which is less than the mass of commercial frames on the market.

V magistrskem delu bomo najprej predstavili standardni način dvodimenzionalnega magnetnoresonančnega slikanja z uporabo standardnih linearnih gradientnih tuljav, ki proizvajajo prostorsko linearno odvisno magnetno polje. Nato bomo obravnavali alternativno magnetnoresonančno slikanje z uporabo nestandardnih nelinearnih gradientnih tuljav, kjer ima njihovo magnetno polje bolj splošno prostorsko odvisnost. Kot primer bomo predstavili preprosto gradientno tuljavo z obliko pravokotne zanke, kjer le ena stranica z ravnim odsekom žice ustvarja za slikanje pomemben gradient magnetnega polja. Geometrijske deformacije v MR slikah lahko izračunamo iz prostorske porazdelitve projekcije magnetnega polja $B_z$ gradientne tuljave. Izdelali smo model takšne tuljave in z njo opravili slikanje. Dobljene slike smo nato primerjali s teoretično napovedanimi. Razumevanje popačitev v MR slikah pri uporabi nelinearnih gradientnih tuljav nam omogoči, da lahko rekonstruiramo geometrijsko nepopačene slike tudi z uporabo takšnih tuljav. To je lahko koristno, ker lahko oblikujemo tovrstne nekonvencionalne tuljave na način, ki nam pomaga odpraviti raznovrstne slabosti standardnih gradientnih tuljav. In this thesis we present the standard way of making two-dimensional magnetic resonance images with use of standard linear gradient coils that feature spatially linear magnetic fields. We also discuss the alternative imaging with non-standard non-linear gradient coils that have more general spatial magnetic field dependency. As an example, we will present a simple gradient coil with the shape of a rectangle, where only a single edge produces for imaging significant gradient of the magnetic field. Image distortions can be calculated from the known spatial dependency of the magnetic field $B_z$ of the gradient coil. We made a model of such coil and used it for imaging. We used produced images to compare theoretical predications with the experimental results. Understanding of image distortions due to the use of nonlinear gradient coil designs enables us to reconstruct distortion-free images acquired by the use of such coils. This can be beneficial as these special coils can be designed to reduce specific weaknesses of standard gradient coils.

Pri uporabi aditivnih tehnologij lahko tiskamo izdelke z zelo širokim naborom filamentov, ki so običajno mešanica nekega izbranega materiala in polimerov, ki se vežejo v obliko. Določitev materialnih lastnosti polimernih materialov, kot so natezna trdnost in elastični modul, se lahko določi v sladu s standardnim nateznim preizkusom. Za razliko od kovinskih materialov so pri nateznem testu 3D tiskanih polimernih materialov potrebne spremembe, ki se navezujejo predvsem na hitrost obremenjevanja ter način vpetja vzorcev in so natančneje opredeljene v standardih ISO 527 in ASTM D 638. Cilj magistrske naloge je zasnovati ter izdelati trgalno napravo za izvedbo nateznega testa skladno z ISO 527 standardom in izvesti vzorčne meritve za opredelitev ustreznosti in natančnosti naprave. When using additive technologies, we can print products with a very wide range of filaments, which are usually a mixture of a selected material and polymers that bind to form. The determination of the material properties of polymeric materials, such as tensile strength and elastic modulus, can be determined by a standard tensile test. Unlike metal materials, the tensile test of 3D printed polymer materials requires changes that relate to the load speed, the method of holding the samples and are defined in detail in ISO 527 and ASTM D 638. The aim of the master's thesis is to design and manufacture a tensile testing device, perform a tensile test in accordance with the ISO 527 standard and perform sample measurements to determine accuracy of the device.

Pri periodičnih pregledih jedrskih elektrarn je pogosto uporabljena metoda vizualnega pregleda, pri kateri je stopnja degradacije komponent ocenjena na podlagi slik ali videoposnetkov. Na mestih pregleda, kjer zaradi premočnega sevanja dostop ni mogoč, je potrebno uporabiti namenske pripomočke ali daljinsko vodene sisteme. Cilj naloge je razviti in izdelati daljinsko vodenega mobilnega robota za izvajanje vizualnih pregledov reaktorske glave in ga preizkusiti na namenski maketi. Za prototipiranje in izdelavo robota je bila uporabljena tehnologija 3D tiskanja, kjer smo na podlagi mehanskih, kemičnih in temperaturnih lastnosti izbrali najustreznejši material za okolje, v katerembo robot opravljal delo. Za opravljanje inšpekcije je bilo potrebno izbrati dimenzijsko ustrezno kamero. Poleg tega je bilo potrebno izbrati primerne elektronske komponente: mikrokrmilnik in gonilnike za vodenje mobilnega robota ter mikroračunalnik za komuniciranje z operaterjem. Razviti je bilo potrebno vse programske vmesnike za vodenje robota ter za prenos in zajem slike. Izdelana je bila aplikacija, ki povezuje celotno delovanje sistema, da bo operater lažje uporabljal robota. Mobilni robot je bil testiran na namenski maketi in ob izpostavitvi ionizirajočemu sevanju. Tako smo preizkusili ustreznost slike, ki jo zajema kamera na robotu in ki služi kot dokazovanje stanja pregledanih komponent med inšpekcijo. Periodic inspections of nuclear power plants often use the visual inspection method, in which the degree of decomposition of a component is estimated on the basis of images or videos. At inspection points where access is not possible due to excessive radiation a use of dedicated tools or remote control systems are required. The aim of the task is to develop and manufacture remotely controlled mobile robot for performing visual inspections of the reactor head and to test it on the polygon. 3D printing technology was used for prototyping and manufacturing robot, where we selected the most suitable material for the enviroment where the robot will be performing tasks on the basis of mechanical, chemical and temperature properties. To carry out the inspections, it was necessary to select an appropriate camera. Furthermore the primary electronic components had to be selected: a microcontroller and drivers to control the mobile robot, and a microcomputer to communicate with the operator. All software interfaces for robot control, image transfer and capture had been developed. An application that connects the entire operation of the system to make it easier for the operator to use the robot was created. The mobile robot was tested on the polygon and was exposed to ionizing radiation. Thus, we tested the adequacy of the images captured by the camera on the robot.

Namen dela je bila izdelava krmilnega algoritma, ki uspešno prilagaja višino varilnega gorilnika med postopkom obločnega oblikovnega navarjanja. Opisana je raziskava krmiljenja višine navarjanja kovinskega materiala s postopkom obločnega navarjanja v zaščiti aktivnega plina (MAG). Varilni gorilnik je bil pritrjen na stojalo, pod njim pa je bila pomično vpeta 3-osna CNC miza. Po vsaki dokončani plasti smo z izmerjeno vrednostjo jakosti varilnega toka izračunali pomik varilnega gorilnika po višini. Uspešno smo izdelali algoritem za nastavljanje višine gorilnika, ki na podlagi meritev jakosti varilnega toka pomika varilni gorilnik znotraj nastavljenih mejnih vrednosti. S tem zagotavljamo konstantno oddaljenost varilnega gorilnika od izdelka med varjenjem posameznih plasti pri varjenju izdelkov z večjim številom slojev. Krmilni algoritem omogoča ponovljivo izdelovanje izdelkov brez pretiranega ugotavljanja višine posamezne plasti pri obločnem oblikovnem navarjanju. In this thesis a research regarding layer height control of mild steel is conducted. The goal was to make a computer algorithm, with which we can successfully control the height of the welding torch during the process of additive welding. The proces used was metal active gas (MAG). Welding gun was attached to a stand and a CNC table was movably mounted below it. With it we achieved movement in three axes, x, y and z. Through experiments conducted we calculated the ratio between the distance of the welding gun from the welding piece and welding current. After each finished layer we calculated height increment of the welding torch in the next layer. We successfully built an algorithm that allowed height control of the welding torch within the set limits, during the process of additive welding. With it a constant distance between the welding piece and welding torch is maintained when welding pieces with a large number of layers. This algorithm enables us to reproduce products without excessive determination of individual layer height during additive welding.

Izdelava pohištva zaobljenih, organskih oblik običajno pomeni slabši izkoristek materiala, veliko ročnih/strojnih obdelovalnih ur ter posledično tudi višji strošek izdelave stola. Z uporabo specializiranih programov za modeliranje je mogoče izdelati model in njegove variante ter že v fazi razvoja predvideti njegovo izdelavo s CNC stroji, tako da je izkoristek materialov čim boljši ter obdelovalni čas čim krajši. S programom SolidWorks smo konstruirali in oblikovali stol na osnovi naravne oblike rečnega kamna prodnika. Izdelali smo več variant 3D modelov različnih oblik in dimenzij ter nato izbrano varianto s tehnologijo 3D tiska izdelali kot model v merilu 1:5. V fazi razvoja smo predvideli načine izdelave ter detajle konstrukcije z optimalno izrabo materiala ter obdelovalnih časov. Sledila je izdelava stola iz bloka zlepljenih bukovih vezanih plošč s tehnologijo rezkanja na 5-osnem CNC stroju ter površinska obdelava izdelka. Manufacture of furniture of round, organic shapes usually means poor utilization of material, a large number of manual/machine working hours and consequentially also a higher cost of the product. Using specialized programmes for modelling it is possible to make a model with its variants, and already in the stage of development anticipate its production with CNC machines to use less material and to reduce working hours. Using the SolidWorks programme, a stool on the basis of the natural shape of pebble stone was designed and constructed. Several variants of 3D models with different shapes and dimensions were made, and afterwards the chosen variant was manufactured as a model on a 1:5 scale with the technology of 3D printing. In the stage of development different methods of manufacture and details of construction with the optimal utilization of the material and working hours were anticipated. This was followed by the manufacturing of the product made from a block of glued beech plywood panels with the technology of milling on 5 axis CNC machine and surface treatment.

Pri izdelavi izdelka s 3D tiskanjem lahko nastavimo številne parametre, ki vplivajo na izgled in lastnosti izdelka. Eden izmed nastavljivih parametrov, je hitrost tiskanja. S spremembo hitrosti tiskanja se spremeni tudi viskoznost materiala, ki ga ekstrudiramo in s tem lastnosti izdelka. V zaključni nalogi smo iskali hitrostno območje v katerem so izdelki narejeni s tehnologijo 3D tiskanja najkvalitetnejši. V teoretičnem delu smo si pogledali kako deluje 3D tiskalnik po metodi ciljnega nanašanja plasti, kako vplivata temperatura in hitrost tiskanja na viskoznost ter princip delovanja tritočkovnega upogibnega testa. S 3D tiskalnikom smo izdelali vzorce pri različnih hitrostih tiskanja, ki smo jih preizkušali s pomočjo tritočkovnega upogibnega testa. Na koncu smo vzorce vrednotili na podlagi vizualnega izgleda in odstopanj dimenzij ter na podlagi mehanskih lastnosti pridobljenih iz upogibnega testa. When creating a product with 3D printing, we can set a number of parameters that affect the appearence and properties of the product. One of the adjustable parameters is the printing speed. By changing the printing speed, the viscosity of the material to be extruded also changes, and thus the properties of the product can change. In the final task of this thesis, we studied for the speed range, in which the products, made with 3D printing technology, would have the highest quality. In theoretical part of the thesis, we studied at how a 3D printer works according to the method of fused filament fabrication, how temperature and print speed affect the viscosity and the principles of operation of a three-point bending test. Using a 3D printer, we produced several samples at different printing speeds, which have been tested with a three-point bending test. Finally, the samples were evaluated on the basis of visual appearance and dimensional deviations, and on the basis of mechanical properties obtained from the bending test.

V nalogi smo primerjali programsko opremo različnih ponudnikov s stališča podpornih struktur pri 3D tiskanju po metodi ciljnega nalaganja (anlg. fused deposition modeling). Programsko opremo smo primerjali glede na čas tiskanja in količino porabljenega materiala za tisk podpornih struktur pri različnih vrednostih parametrov podpornih struktur. Ugotovili smo, kateri tip podpornih struktur in kateri način postavitve porabi več časa in materiala za tisk. Primerjali smo, kako se poraba materiala in čas tiskanja spremenita pri spremembi parametrov podpornih struktur. Glede na izbrane kriterije Ultimaker Cura gradi najbolj optimalne drevesne podporne strukture in PrusaSlicer gradi najbolj optimalne drevesne podporne strukture. Different providers’ software was analysed in terms of support structures by fused deposition modeling 3D printing. Two features of software for printing support structures were compared, namely printing time and consumed material by setting different parameters of support structures. The goal was to find out which type and way of placement of support structures is the most effective in terms of printing time and material consumption. By changing different parameters, the printing times and material consumption were compared. Based on selected criteria PrusaSlicer generates the most optimal linear support structures and Ultimaker Cura generates the most optimal tree-like support structures.

Tehnologija 3D tiskanja je v zadnjih letih doživela velik razvoj tudi na področju živilske industrije. V diplomskem delu smo najprej predstavili osnovno delovanje, konfiguracije in metode tiskanja 3D tiskalnikov, ki se najpogosteje uporabljajo pri tehnologiji aditivne proizvodnje. V nadaljevanju smo preučili primerne materiale, njihove lastnosti in primere uporabe. Pri posameznih materialih smo se osredotočili na pomen predobdelave in njen vpliv na proces 3D tiskanja. Ugotovili smo, da so za izboljšanje reoloških, strukturnih in senzoričnih lastnosti zelo pomembni aditivi, saj osnovni materiali v veliki večini niso primerni za uporabo. Tehnologija 3D tiskanja živil ima velik potencial pri izdelovanju prilagojenih izdelkov, namenjenih predvsem ljudem, ki so zaradi različnih razlogov nagnjeni k podhranjenosti. Komercializacija 3D tiskalnikov bi pomenila ogromno spremembo proizvodnje in načina uživanja hrane kot je poznamo. Tehnologija 3D tiskanja bi imela tudi pozitiven ekološki vpliv, saj poveča izkoristek surovin, zaradi česar nastaja manj odpadkov. Tehnologija trenutno ni konkurenčna ustaljenim proizvodnim procesom, saj je razmeroma nova in potrebuje še veliko raziskav, testiranj in izboljšav. 3D food printing technology has immensely developed in the last few years. The aim of this work is to present the working principle of 3D printers, possible combinations of configurations and printing methods of 3D printers. We also examined materials suitable for usage, their characteristics and their possible applications. We emphasized the meaning of pre-processing of the materials to improve the process of 3D printing. We discussed the importance of additives and how they affect rheological, structural and sensory properties of the used materials. 3D printing technology has a lot of potential for creating personalized food, intended for people prone to malnutrition. Commercialization of 3D food printers would completely change traditional food production. It would also have a positive impact on the environment, because the technology is more efficient, therefore it does not produce much waste. Currently 3D printing technology is not competitive with traditional food manufacturing and is in need of more research and improvements.

Akvaristika je eden najbolj razširjenih domačih konjičkov. Za vzdrževanje živih bitij v akvariju in za estetski videz so pomembni različni specializirani pripomočki, kot so filter, grelec za vodo, luči in hranilnik. Na tržišču so ti pripomočki na voljo ločeno in delujejo nepovezano. Cilj diplomske naloge je bil prenoviti, razviti, izdelati in uporabiti nov produkt za pomoč akvaristom. Sistem avtomatskega sistemsko integriranega nizko-profilnega hranilnika rib je sestavljen iz dveh glavnih komponent: sistemskega krmilnika in avtomatskega hranilnika. Razvijali smo programsko opremo za krmiljenje celotnega sistema akvarija in izdelali novo vrsto hranilnika za ribe. Hranilnik je zasnovan z uporabo napredne pogramske opreme za 3D-modeliranje. Za izdelavo hranilnika smo uporabili dve nekonvencionalni metodi: 3D-tiskanje in rezanje z abrazivnim vodnim curkom. Za sistemski krmilnik smo uporabili mikrokrmilnik Arduino, ki smo ga programirali v programskem jeziku C++. Izdelek smo preizkusili v praksi. Pri tem je zadostil vsem zahtevam uporabe in estetike. Odporen je proti vlagi in omogoča večdnevno hranjenje rib. Sistem upravlja filter, LED-svetilke in hranilnike. Z avtomatskim sistemsko integriranim nizko-profilnim hranilnikom rib smo uresničili zastavljene cilje. Uporabnikom smo olajšali vzdrževanje in upravljanje akvarija in dosegli želeni estetski videz. Predstavili smo pogoje uporabe in na podlagi testiranja predlagali izboljšave izdelka. Aquaristics is one of the most widespread domestic hobbies. Various specialized devices such as a filter, a water heater and lights are used to keep the stocking of the aquarium alive and well. All of the products available on the market today are not connected to any communal system. Instead, they all work independently. The aim of the thesis was to innovate, develop, manufacture and use a new product used to help aquarists. System of a low-profile system integrated fish feeder is built in two main parts. The fish feeder itself and a main system computer. We developed software which controls the whole aquarium. The fish feeder was designed using the latest in 3D modelling technology. For the manufacturing we used two unconventional manufacturing methods. 3D Printing and abrasive water jet cutting. For the system computer we used an Arduino microcontroller, which was programmed in C++ programing language. The product was tested and it achieved all of our initial goals. It successfully repels moisture and allows for the end user to be absent for multiple days. The system controls the filter, LED lights and the fish feeder itself. Users have now less work to do and the esthetic purpose of an aquarium was not compromised. The operating conditions were measured and improvements, based on the findings were proposed.

Na trgu imamo veliko izbiro 3D tiskalnikov z metodo ciljnega nalaganja. Cene se lahko gibljejo od 100 € do 7000 €. V diplomskem delu je predstavljeno kako smo cenovno ugodnemu 3D tiskalniku Creality Ender 3 povečali kvaliteto tiskanja, ki se lahko primerja s 3D tiskalniki Ultimaker, ki so višjega cenovnega razreda. Teoretični del diplomskega dela zajema glavne lastnosti tiskalnikov in izdelke, ki jih bomo uporabljali za primerjavo. Sledi prikaz vseh problemov na 3D tiskalniku Creality Ender 3 in kako smo te probleme rešili. Na koncu smo primerjali izdelke natisnjene na 3D tiskalnikih Creality Ender 3 in Ultimaker, kjer smo z rezultati pokazali, da predelani tiskalnik Creality Ender 3 dosega podobno kvaliteto izdelkov kot tiskalnika Ultimaker 2 in 3. There is a currently a wide variety of 3D printers, based on the process of fused deposition modelling available on the market. The price can vary anywhere between €100 and €700. The aim of this Bachelor’s thesis was to present the process of improving the print quality of an affordable 3D printer, the Creality Ender 3, which is on a par with the higher priced Ultimaker 3D printer range. The theoretical part of the thesis covers the main features of printers and the products which will be used for comparison. It is followed by a description of all the problems of the Ender 3 3D printer and how we managed to solve them. Finally we will compare the results of the finished prints made on the Ender 3 and Ultimaker 3D printers, where we have shown that the modified Ender 3 printer can compare with the print quality of competitors like Ultimaker 2 and 3.

V podjetju BigRep je bil ustvarjen profil za tiskanje materiala s kovinskim prahom Ultrafuse 316LX za 3D tiskalnik BigRep STUDIO G2. Profil z izbranimi parametri za tiskanje, v programskem orodju BLADE, omogoča 3D tiskanje kompozitnega materiala polimera z dodatkom nerjavečega jekla (okoli 80 mas. %). Model je najprej ustvarjen v programski opremi za 3D modeliranje. Sledi pretvorba digitalne datoteke v .stl format. Model se v programskem orodju za razrez razdeli na sloje določene višine ki so natisnjeni na 3D tiskalniku. Po končanem tiskanju sledita postopka odstranjevanja veziva in sintranje. Rezultat je popolnoma kovinski produkt. Diplomsko delo predstavlja pogled v razvoj in uporabo aditivne tehnologije. V eksperimentalnem delu so bili izvedeni različni testi optimizacije profila. Med drugimi lastnostmi so bile določene vrednosti optimalne temperature tiskanja, največje hitrosti, največjega možnega kota tiskanja, možnost tiskanja z različnimi vrstami podpore, izboljšana je bila adhezija na tiskalno podlago. Po končanem tisku so bile izmerjene dimenzijske vrednosti modelov v treh smereh. Poslani so bili podjetju BASF, kjer sta bila izvedena procesa odstranitve veziva in sintranje. Iz ponovnih meritev je bil izračunan skrček med procesom sintranja. S pomočjo te vrednosti je mogoče načrtovati dimenzijsko ustrezne modele v prihodnosti. Izveden je bil tisk modela diska s hladilnim kanalom, ki predstavlja geometrijo, ki jo je težko izdelati s tradicionalnimi metodami. Z namenom prikaza možnosti uporabe materiala je bila prav tako natisnjena serija modelov različnih geometrij. The development of the printing profile of Ultrafuse 316LX material for 3D printer BigRep STUDIO G2 was made while working in the BigRep 3D printing Company. The profile parameters in slicing software BLADE enable 3D printing of the composite material made from polymers with addition of stainless steel particles (around 80 wt. %). At the beginning the model is designed in 3D CAD software. Then the digital file is converted to .stl format. Slicer software is used to cut the model in slices with certain height and printed on 3D printer. After the printing, the part goes through processes of debinding and sintering. The result is completely metal product. The thesis presents a view on the development and usage of additive technology. In the experimental work test were made to insure optimisation of the profile. Optimal values for the following parameters were assigned: temperature of printing, maximal speed, maximal angle of printing, possibility of printing with support, bed adhesion was improved. After the printing was complete measurements of the part were made in X, Y and Z direction. Parts were sent to the company BASF where they were implemented to the processes of debinding and sintering. With the measurements after sintering process shrinkage was calculated. This value enables the design of dimensional accurate parts in the future. A disk with cooling channel was produced with this method. It represents geometry that is hard to produce with traditional methods of production. A series of different models were also printed to show the areas of possible application for the material.

Namen zaključne naloge je raziskava in določitev vpliva temperature tiskanja na mehanske in geometrijske lastnosti 3D tiskanih izdelkov. V okviru naloge smo s pomočjo namiznega 3D tiskalnika Sharebot natisnili vzorce za natezni preizkus standardnih dimenzij po ISO 527. Vzorce smo natisnili s pomočjo filamentov polilaktične kisline (PLA) pri različnih temperaturah šobe na tiskalni glavi, vsi ostali parametri tiskanja so bili ves čas enaki. Temperaturo šobe smo spreminjali v inkrementih po 10°C v območju od 170°C do 230°C. Vpliv temperature na geometrijske lastnosti smo določili z merjenjem geometrije na izbranih mestih, mehanske lastnosti preizkušancev pa smo določili s pomočjo nateznega preizkusa in nanoindentacije. Na podlagi meritev smo želeli določiti optimalno temperaturno območje tiskanja, pri katerem bi 3D tiskani izdelki imeli najboljše mehanske in geometrijske lastnosti. Rezultati meritev so pokazali, da so bili vzorci geometrijsko najbolj stabilni in so imeli najboljše mehanske lastnosti pri tiskanju s temperaturo 200 °C. The purpose of the presented thesis is to investigate the effect of printing temperature on the mechanical and geometric properties of 3D printed polymer products. As part of the study, samples for tensile testing of standard dimensions according to ISO 527 were printed using the Sharebot desktop 3D printer. Samples were printed with polylactid filaments (PLA) at different temperatures of the nozzle on the printhead, while all other printing parameters were kept constant. The nozzle temperature was changed in increments of 10 °C in the range from 170 °C to 230 °C. The influence of printing temperature on the geometric properties was determined by measuring the geometry at selected points, while the mechanical properties of the tested products were determined by tensile test and nanoindentation. On the basis of measurements, we tried to determine the optimal printing temperature range in which 3D printed products would have the best mechanical and geometric properties. The results showed that the samples were geometrically the most stable and had the best mechanical properties at printing temperature of 200 °C.

IZVLEČEK Uvod: Diplomsko delo obravnava praktično uporabnost 3D skeniranja na področju tehnologije pripomočkov za ortotiko in protetiko. V nadaljevanju so predstavljene različne metode 3D skeniranja in tiskanja, njihove prednosti in slabosti ter tudi druga področja, kjer je 3D skeniranje nadvse uporabno. Na kratko je predstavljen pretekli razvoj tehnologije 3D ter izpostavljen možen prihodnji razvoj. Namen: Predstaviti pomen 3D skeniranja kot del digitalizacije človeškega telesa na področju ortotike in protetike. Cilj diplomskega dela predstavlja praktični prikaz in analiza uporabnosti 3D skeniranja na področju ortotike in protetike. Metode dela: Temelji na pregledu literature. Uporabljena metoda dela je teoretična, tj. študij literature. Pri pisanju naloge smo uporabili deskriptivno, opisno metodo dela in pa komparativno metodo dela. Gradivo smo iskali v spletnih bazah podatkov COBISS, MEDLINE, PubMed, DiKUL ter Google Scholar. Rezultati: Osrednji del predstavlja prikaz in analizo nekaterih praktičnih primerov 3D skeniranja na področju izdelave prilagojene ortotike in protetike za posameznega uporabnika oz. pacienta. Le-to smo uvrstili v poglavje Rezultati, kjer smo tudi navedli razlike med različnimi vrstami skenerjev, upoštevajoč seveda tiste, ki se uporabljajo v kliničnih okoljih. Razprava in zaključek: Zaključujemo z ugotovitvami, da ima 3D skeniranje na področju protetike in ortotike mnogo prednosti (z vidika dostopnosti, stroškov, uporabnosti, izdelave, inovativnosti), da zahteva vključenost in dobro sodelovanje različnih strokovnjakov, osvetlili pa smo tudi njihov možen prihodnji razvoj ter nekatera etična vprašanja, ki se ob tem porajajo. Introduction: Thesis is researching practical usability of 3D scanning technology in the field of orthopedic and prosthetic devices. Various 3D scanning and printing methods along with their advantages and disadvantages are being presented as well as other areas where 3D scanning is at most useful. Thesis also shortly presents past development of 3D technology and points out possible future development. Purpose: Present the importance of 3D scanning as part of digitization of human body in the field of prosthetics and orthotics. Aim of the thesis is to present practical demonstration and analysis of usability of 3D scanning in the field if orthotics and prosthetics. Methods: Paper is based on literature such as books, articles, magazines, web content, graphic material etc. Method used for this thesis is theoretical such as studying the literature. When writing this paper we have used descriptive and comparative method. We searched for material in online databases COBISS, MEDLINE, PubMed, DiKUL and Google Scholar. Results: Main part of the thesis is presenting demonstration and analysis of some practical examples of 3D scanning in the field of making adapted orthotics and prosthetics for an individual user or patient. This was inserted in chapter Results, where we have stated the differences between different scanner types, considering only those which are being used in clinical environments. Discussion and conclusion: Thesis was concluded with findings, that 3D scanning in the field of prosthetics and orthotics has many advantages (availability, costs, usefulness, manufacturing and innovation, etc.). It also requires inclusion and good cooperation of various experts and we have also shed a light to its possible future development along with some ethnic issues that arise.

To diplomsko delo se osredotoča na varnostni vidik zlorabe tehnologije 3D tiskanja in na izziv varnostne službe na Letališču Jožeta Pučnika Ljubljana, pri odkrivanju takšnih predmetov z načinom varnostnih postopkov, ki jih na omenjenem letališču izvajajo. Vedno bolj se namreč povečuje in je priljubljena uporaba 3D tiskalnikov v zasebne namene. Zaradi neomejenih možnosti uporabe in zaradi neštetih oblik predmetov, ki jih lahko natisnemo s 3D tiskalnikom, lahko potencialni napadalec izdela tudi predmet, ki bi predstavljal grožnjo za varnost. Kljub priljubljenosti in vedno večji vsakdanji zasebni uporabi tehnologij 3D tiskanja, je potrebno opozoriti tudi na možnosti zlorabe, oziroma opozoriti na nevarne predmete narejene s 3D tiskalnikom. Ker se v zadnjih letih v letalskem prometu posveča zelo veliko pozornosti sami varnosti potnikov, smo se v diplomskem delu osredotočili na varnostni pregled oseb in ročne prtljage pred vstopom v varovano območje z omejenim gibanjem oz. v območje izhodov. Hkrati smo se vprašali, kako lahko odkrivanje nevarnih predmetov natisnjenih s 3D tiskalnikom predstavlja težavo varnostni službi. Empirični del diplomskega dela se osredotoča na raziskovalna vprašanja, na katere smo skušali odgovoriti s pomočjo znanstvene literature, osredotoča se na intervju z vodjem varnosti in varovanja na Letališču Jožeta Pučnika Ljubljana, ter na eksperiment, v katerem smo nož, natisnjen s 3D tiskalnikom, izpostavili pregledu z rentgensko napravo, kakršno uporabljajo na prej omenjenem letališču pri varnostnih pregledih. Rezultati so pokazali, da odkrivanje takšnih predmetov predstavlja varnostno tveganje in velik izziv za delo varnostne službe. This diploma thesis focuses on the security aspect of the misuse of 3D printing technology and the challenge of the security service at Jože Pučnik Ljubljana airport, in detecting such objects by methods of security procedures carried out at that airport. The use of 3D printers is increasing and getting popular for private purposes more and more every day. Due to its unlimited use and its innumerable forms of objects that can be printed with a 3D printer, a potential attacker can also create an object that would pose a security threat. Despite the popularity and the daily-increasing private use of 3D printing technologies, it is necessary to point out the possibilities of abuse, or to point out dangerous objects made with the 3D printer. Since in recent years air traffic has paid very high attention to the safety of passengers, this diploma thesis focuses on the security check of persons and cabin baggage before entering the restricted area with limited movement, or to the range of exits, and to the possibilities of how detecting dangerous items printed with a 3D printer poses a problem to the security service. The empirical part of the diploma thesis focuses on the research questions that we tried to answer with the help of scientific literature, it concentrates on the interview with the Head of Safety & Security at Jože Pučnik Ljubljana airport, and on the experiment in which we exposed a 3D printed knife to an X-ray device examination as used at the aforementioned airport for security checks. The results showed that the detection of such objects poses a safety risk and a major challenge for the work of the security service.

Gyroid structured green biocomposites with different thickness face layers (0.5, 1, 2 and 2.5 mm) were additively manufactured from wood/ polylactic acid (PLA) filaments using a 3D printer. The mechanical properties of the composite panels, bending properties, compressive strength (parallel to the surface), Brinell hardness, and face screw withdrawal resistance, were determined. The surface layer thickness significantly affects the mechanical properties of the composite materials. As the surface layer thickness was increased from 0.5 to 2.5 mm, all the mechanical properties significantly improved. In particular, the Brinell hardness and face screw withdrawal resistance of the specimens improved sharply when the skin thickness was higher than 2 mm. The bending strength, bending modulus, compressive strength (parallel to the surface), Brinell hardness, and face screw withdrawal resistance of the specimens with a skin of 0.5 mm were found to be 8.10, 847.5, 3.52, 2.12 and 445 N, respectively, while they were found to be 65.8, 11.82, 2492.2, 14.62, 26 and 1475 N for the specimens with a 2.5 mm skin. Based on the findings from the present study, gyroid structured composites with a thickness of 2 mm or higher are recommended due to their better mechanical properties as compared to the composites with skins that are thinner. Slovenian Research AgencySlovenian Research Agency - Slovenia [P4-0015] The authors would like to thank the Slovenian Research Agency for financial support within the scope of the program P4-0015. The authors also thank the Research Fund of Istanbul University-Cerrahpasa and Kalasalingam Academy of Research and Education regarding use of laboratory test equipment.

Tehnologija 3D modeliranja se je v zadnjih desetletjih razvila do te mere, da lahko skoraj vsakdo doma na svojem računalniku izdela realistične 3D modele s programsko opremo za 3D modeliranje. Del 3D modeliranja pa je tudi 3D kiparstvo, ki omogoča še izdelavo več stopnj podrobnosti in uprizoritev organskih oblik, ki bi jih pri navadnem 3D modeliranju lahko dosegli le s pomočjo tekstur ali 3D mapiranja. Cilj diplomske naloge je uprizoriti čim bolj realistično repliko objekta organske oblike. Ta model nameravamo potem še prototipirati s 3D tiskalnikom in ga dokončati do te mere, da bo deloval organsko in naravno. Technology of 3D modeling evolved in ten years to the point where anyone can create their own 3D models at home, with program tools on their own personal computers. A part of 3D modeling is also 3D sculpting, which can be used to create highly detailed 3D models and show organic shapes which can otherwise show only through textures and 3D maps. The main point of the diploma is to show a realistic looking 3D replica of an organic object. We will also prototype the model with 3D printing technology. We will then finish and paint the model to make it look natural and real.

Tridimenzijsko (3D) tiskanje je vedno bolj priljubljeno tako kot orodje za hitro prototipiranje kot za tiskanje doma. Za tiskanje kakovostnih izdelkov je potrebno nastaviti ustrezne izdelovalne parametre. Izbrani materiali so bili akrilonitril butadien stiren (ABS), polilaurillaktam (PA12), polietilen tereftalat glikol (PETG), polilaktična kislina (PLA) in termoplastični poliuretan (TPU), saj spadajo med najpogostejše skupine polimernih materialov, ki se uporabljajo za 3D tisk. Zaključna naloga obsega proučevanje vpliva temperature na viskoznost izbranih polimernih materialov za 3D tisk. Viskoznost smo proučili z rotacijskim reometrom znotraj temperaturnega območja, ki ga predpisuje proizvajalec za določen material ter primerjali viskoznost vseh materialov pri isti temperaturi. Ugotovili smo, da temperatura različno vpliva na posamezen material, viskoznost posameznega materiala je bistveno drugačna. Prav tako se razlikuje viskoelastičen odziv. Threedimensional (3D) printing is becoming increasingly popular as a tool for rapid prototyping as well as home printing. To print products of high quality, correct manufacturing parameters need to be set. Selected in the present study acrylonitrile butadiene styrene (ABS), polyurylactamate (PA12), polyethylene terephthalate glycol (PETG), polylactic acid (PLA) and thermoplastic polyurethane (TPU) were selected, as they belong to the most popular groups of polymeric 3D printing materials. In this study we studied the effect of temperature on the viscosity of selected materials. Viscosity was measured with a rotational rheometer within the temperature range specified by the manufacturer for a given material. Viscosities of all materials compared at a selected temperature. The results showed that the temperature has a different effect on each material, ergo the viscosity of each material is significantly different. The viscoelastic response also differed.

V diplomski nalogi je predstavljena izdelava prototipa glave filtra za komprimiran zrak z uporabo 3D tiskanja in vključuje idejno zasnovo, modeliranje, pripravo na tisk in tiskanje končnega izdelka po dveh različnih tehnologijah 3D tiska. Za uporabo 3D natisnjenega izdelka pri aplikaciji stisnjenega zraka, mora biti ta neprepusten in prenesti zahtevan nadtlak. V tem delu je prikazana vizualna in funkcionalna primerjava ter izvedba merjenja porušitvenega tlaka obeh natisnjenih prototipov. Dodatno je z računalniško simulacijo izvedena določitev tlačnega padca pri delovnih pogojih prototipa filtra, ki ima drugačno zasnovo zaradi zagotavljanja nižjega tlačnega padca. Rezultati kažejo, da je tisk s tehnologijo brizganja fotopolimera lahko uporaben za izdelavo tlačno obremenjenih izdelkov, saj je izdelek prenesel 11 bar nadtlaka, medtem ko izdelek, natisnjen s tehnologijo ciljnega nanašanja polimera, ni zagotavljal neprepustnosti in zato ni primeren za uporabo pri tlačnih aplikacijah. Računalniška določitev tlačnega padca pa nam je pokazala, da drugačna zasnova filtrske glave ne zagotavlja izrazitega zmanjšanja tlačnega padca v primerjavi z obstoječimi filtrskimi glavami konvencionalne zasnove. This diploma thesis presents the production of compressed air filter head prototype using 3D print technology and includes conceptual design, modeling, print preparation and product printing with two different 3D print technologies. If 3D printed product is intended for compressed air application, it must guarantee fluid impermeability and withstand required pressure. Therefore, this thesis presents visual and functional comparison and also implementation of bursting pressure measurement of both printed products. Additionally, pressure drop of filter prototype under working conditions is determined using computer flow simulation, where structural design of filter head prototype is different than conventional to reach lower pressure drop. The results indicate, that the material jetting print technology is suitable for production of products, which are intended for compressed air applications, as the printed product did withstand a maximum pressure of 11 bar, whereas fused deposition modeling technology is not suitable, as the impermeability of the printed product was not achieved. Computer pressure drop measurements revealed, that different structural design of this filter head prototype does not guarantee noticeable lower pressure drop compared to the conventional design of filter head.

Tema ovog diplomskog rada je primjena robota za izradu prototipova postupkom 3D tiskanja. U uvodom dijelu objašnjen je proces 3D tiskanja, poglavito postupak taložnog očvršćivanja (eng. Fused Deposition Modeling – FDM) koji je primijenjen u radu. Potom je dan pregled elemenata koji su potrebni za razvoj upravljanja 3D tiskačem na Arduino platformi. U nastavku su oblikovani dijelovi za montažu sklopa za 3D tiskanje na robotsku ruku. Za generiranje trajektorija nanošenja materijala po slojevima korišten je softver RoboDK, a za podešavanje parametra Slic3r. U radu je također razvijen program za upravljanje koračnim motorom ekstrudera i provedena je regulacija nekih parametara. U drugome dijelu rada prikazani su rezultati provedenih testiranja, preporuke, komentari i ponuđena rješenja za postizanje bolje kvalitete izrade modela. The topic of this master thesis is prototyping using a robotic 3D printer. The introduction part describes the process of 3D printing, in particular, the Fused Deposition Modeling – FDM procedure which was used in the thesis. After that is a review of the elements which are needed for development of 3D printing control system on Arduino. In the following chapter the parts for the assembly of the 3D printer on the robot are designed. RoboDK software was used to generate layer by layer trajectory and Slic3r software was used to define parameters. In this thesis a program for controlling the stepper motor of the extruder was developed and regulation of some paramaters was carried out. In the second part of this thesis, the results of testing, recommendations, comments are presented and solutions for better model production are offered.

Additive manufacturing is becoming increasingly important for manufacturing end products, not just prototyping. However, the size of 3D-printed products is limited due to available printer sizes and other technological limitations. For example, making furniture from 3D-printed parts and wooden elements requires adequate adhesive joints. Since materials for 3D printing usually do not bond very well with adhesives designed for woodworking, they require special surface preparation to improve adhesion. In this study, fused deposition modelling (FDM) 3D-printed parts made of polylactic acid (PLA), polylactic acid with wood flour additive (Wood-PLA), and acrylonitrile-butadiene-styrene (ABS) polymers were bonded to wood with polyvinyl acetate (PVAc) adhesive. The surfaces of the samples were bonded as either non-treated, sanded, plasma treated, or sanded and plasma treated to evaluate the effect of each surface preparation on the bondability of the 3D-printed surfaces. Different surface preparations affected the bond shear strength in different ways. The plasma treatment significantly reduced water contact angles on all tested printing materials and increased the bond tensile shear strength of the adhesive used. The increase in bond strength was highest for the surfaces that had been both sanded and plasma treated. The highest increase was found for the ABS material (untreated 0.05 MPa, sanded and plasma treated 4.83 MPa) followed by Wood-PLA (from 0.45 MPa to 3.96 MPa) and PLA (from 0.55 MPa to 3.72 MPa). Analysis with a scanning electron microscope showed the smooth surfaces of the 3D-printed parts, which became rougher with sanding with more protruded particles, but plasma treatment partially melted the surface structures on the thermoplastic polymer surfaces.

Danes je uporaba aditivnih tehnologij v proizvodnji vse bolj pogosta, saj omogočajo izdelavo kompleksnih geometrij z majhno porabo materiala. Aditivne tehnologije, ki uporabljajo kovinske prahove so pogosto povezane z visokimi stroški in omejenostjo na izdelavo manjših izdelkov. Za naše preizkuse smo uporabljali tehnologijo obločnega navarjanja žice po postopku CMT (nadgradnja postopka MIG). V nalogi smo se osredotočili predvsem na analizo medvarkovnih temperatur in vpliv le teh na kakovost izdelka. Ugotovili smo, da medvarkovna temperatura ne sme preseči 130 °C, drugače pride do napak v izdelku. Poleg tega smo spoznali, da se medvarkovna temperatura spreminja enakomerno s temperaturo podlage, kar pomeni da moramo za hitrejše znižanje medvarkovne temperature hladiti podlago. Today, the use of additive technologies in production is becoming increasingly common as it enables the production of complex geometries with low material consumption. Additive technologies that use metal powders are often associated with high costs and production of smaller products. For our experiments we used wire and arc additive manufacturing technology using the CMT procedure (MIG process upgrade). In our work, we focused primarily on the analysis of weld interpass temperatures and the impact of these on product quality. We find out that the weld interpass temperature should not exceed 130 °C, otherwise errors in the product may occur. In addition, we learned that the weld interpass temperature changes evenly with the base temperature, which means that the base should be cooled down to lower the weld interpass temperature.

V zadnjem času je v porastu uporaba novejših proizvodnih tehnologij, s katerimi proizvajamo produkte iz umetno pridobljenih polimernih materialov. Posledično se na trgu pojavlja več izdelkov, ki so izdelani z aditivnimi tehnologijami tiska. V zaključni nalogi smo raziskali združljivost takšnih produktov z bolj konvencionalnimi tehnologijami, kot je združevanje kosov z varjenjem. Preizkušali smo kvaliteto zvarnih spojev iz dveh polimernih kosov, ki smo ju izdelali s 3D tiskanjem po tehnologiji ciljnega nalaganja. Naloga je razdeljena na tri dele. V prvem delu so bili izdelani različni kosi iz polikarbonatnega materiala, v drugem delu so se kosi združili po tehnologiji varjenja polimerov z uporovnimi vsadki, v zadnjem delu so se ustvarjeni spoji porušili na testnem preizkuševališču. Preizkuševališče je bilo zasnovano na podlagi gravitacijske sile teže, ki je statično delovala na zvarni spoj. Meritve so bile razdeljene glede na smer aplicirane sile prečno in vzdolžno. Ugotovili smo, da zvarni spoj zdrži višje obremenitve (povprečna vrednost porušitve je znašala 290 N) pri delovanju statične sile prečno glede na potek zvarnega spoja, kot v vzdolžni smeri (povprečna sila je znašala 280 N). Ponovljivost meritve je bila boljša pri obremenitvi s prečno statično silo. In modern times there is an increase in use of newer manufacturing technologies with which products are being produced from artificial polymer materials. As a consequence more and more products manufactured with additive technologies are on the market. In the thesis we researched compatibilities of such products with more conventional technologies of material joining, like plastic welding. We tested the quality of welded joints, made of two polymer material parts, produced with the 3D printing process fused deposition modeling. The thesis is divided into three main parts firstly different pieces were made from polycarbonate material, in the second part those pieces were welded by plastic welding with resistive implants and in the last part welded joints were destructively tested on a test station. The station was designed to enable the application of gravity force to joints. Measurements were divided by the direction of the applied force according to the joint position transverse and longitudinal. Results show, that the joints which were collapsed by the transverse force, hold greater static load (average force was 290 N) than the ones with the longitudinal force load (average force of those was 280 N). Repeatability was better, when the static load was applied to joints in transverse direction.

Aluminijeve zlitine se veliko uporabljajo pri izdelavi raznih izdelkov, pri katerih je pomembno visoko razmerje med trdnostjo in maso. Pri izdelavi kompleksnih izdelkov pogosto naletimo na tehnološke omejitve izdelave, ali pa želimo zmanjšati stroške in količino odpadnega materiala. Zato se v zadnjem času čedalje bolj uveljavljajo aditivne tehnologije, s katerimi rešujemo te izzive. Naloga se osredotoča na izdelavo baze podatkov pri obločnem navarjanju aluminijeve zlitine AlSi5 in optimiziranje postopka. Testi so opravljeni z varilnim robotom in sinergijskim varilnim virom za varjenje MIG/MAG, uporabljen pa je postopek CMT. Predvsem so podrobno preučeni osnovni varilni parametri, ki omogočajo izdelavo kakovostnih navarjenih sten, analizirano pa je tudi odvajanje toplote in razporeditev le-te po varjencu. Izsledki naloge kažejo, da je ob dobrem obvladovanju vnosa toplotne energije mogoče izdelati vizualno kakovostne stene s širino do 4,5 mm in izkoristki materiala nad 80 % , ki jih je po dodatni mehanski obdelavi možno uporabiti za izdelavo tankostenskih izdelkov. Aluminum alloys are used in the manufacturing of many products that require a high strength to weight ratio. In manufacturing of complex products we often reach the technological limits of conventional manufacturing methods or want to reduce costs and the amount of discarded material. To solve these problems, many types of additive technologies are being developed. This paper focuses on creating a database of parameters and optimization of the wire and arc additive manufacturing method for welding of AlSi5 aluminum alloy. The tests are made using a welding robot in combination with a synergic MIG/MAG welding machine and where CMT welding process is used. The emphasis is on the study of core welding parameters that enable quality welded walls to be made. Heat conduction and its distribution across the welded part is also studied. The results of this paper show that through good heat input management, it is possible to produce quality welded walls with widths up to 4,5 mm and material deposition efficiency above 80 % that, after additional machining, can be used for production of thin-walled products.