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71.
Optimization of extrusion process by genetic algorithms and conventional techniques
Zoran Jurković, Miran Brezočnik, Branko Grizelj, Vesna Mandić, 2009, original scientific article

Abstract: The purpose of this research is the determination of the optimal cold forward extrusion parameters with the minimization of tool load as objective. This paper deals with different optimization approaches in order to determine optimal values of logarithmic strain, die angle and friction factor with the purpose to find minimal tool loading obtained by cold forward extrusion process. Two experimental plans based on factorial design of experiment and orthogonal array have been carried out. Classical optimization, according to the response model of extrusion forming force, and the Taguchi approach are presented. The obtained extrusion force model as the fitness function was used to carry out genetic algorithm optimization. Experimental verification of optimal forming parameters with their influences on the forming forces was also performed. The experimental results show an improvement in the minimization of tool loading. The results of optimal forming parameters obtained with different optimization approaches have been compared and based on that the characteristics analysis (features and limitations) of presented techniques.
Keywords: metal forming, forward extrusion force optimization, design of experiments, Taguchi approach, genetic algortihm
Published: 31.05.2012; Views: 1299; Downloads: 74
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72.
A reverse engineering technique for creating virtual robots
Simon Brezovnik, Miran Brezočnik, Simon Klančnik, Ivo Pahole, Karl Gotlih, 2009, original scientific article

Abstract: A novel system for out-of-date robotic systems that are not interesting for use any more is introduced. We give a solution for revitalization of these robotic systems with upgrading the programming software from on-line programming to indirect virtual programming and virtual modelling of a production cell equipped with robots. Direct and inverse kinematic models of the robot ACMA XR 701 in the virtual space were developed with reverse engineering technologies.
Keywords: robotics, robot modelling, reverse engineering, robot cell
Published: 31.05.2012; Views: 1332; Downloads: 34
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73.
Prediction of the ultraviolet protection of cotton woven fabrics dyed with reactive dystuffs
Polona Dobnik-Dubrovski, Miran Brezočnik, 2009, original scientific article

Abstract: Textile materials provide a simple and convenient protection against UV radiation. To assign the degree of UV radiation protection of textile materials, the Ultraviolet Protection Factor (UPF) is commonly used. This paper reports the effect of woven fabric construction (yarn fineness, type of weave, relative fabric density), the colour of bi-functional reactive dyestuffs, and Cibacron dyed fabrics on the ultraviolet protection of light summer woven fabrics. A predictive model, determined by genetic programming, was derived to describe the influence of fabric construction. Warp and weft densities, weave factor and CIELab colour components were taken into account by developing the prediction model for UPF. The results show very good agreement between the experimental and predicted values.
Keywords: ultraviolet protection factor, woven fabric construction, colour, prediction model, genetic programming
Published: 31.05.2012; Views: 1353; Downloads: 37
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74.
Study of crosslinking efficiency of cotton cellulose by different physical-chemical methods and genetic programming
Olivera Šauperl, Miran Brezočnik, 2006, original scientific article

Abstract: We have investigated the crosslinking effect of unmercerized and mercerized cotton celluose crosslinked with different BTCA mass fractions in the impregnation bath. Crosslinking efficiency was analyzed using FT-IR spectroscopy, water retention capacity method, tensiometry and the methylene blue method. On the basis of the experimental data which was obtained with theseparate physical-chemical methods, different prediction models for crosslinking efficiency was developed. Modelling was taken out with the genetic programming method. Research shows good accordance of the experimentaldata with the genetic models.
Keywords: textile fibres, cotton, cellulose, crosslinking, FTIR spectroscopy, methylene blue method, water retention capacity, tensiometry, genetic programming
Published: 30.05.2012; Views: 1534; Downloads: 59
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75.
Modeling of impact toughness of cold formed material by genetic programming
Leo Gusel, Miran Brezočnik, 2006, original scientific article

Abstract: In the paper, an approach completely different from the conventional methods for determination of accurate models for the change of properties of cold formed material, is presented. This approach is genetic programming (GP) method which is based on imitation of natural evolution of living organisms. The main characteristic of GP is its non-deterministic way of computing. No assumptions about the form and size of expressions were made in advance, but they were left to the self organization and intelligence of evolutionary process. First, copper alloy rods were cold drawn under different conditions and then impact toughness of cold drawn specimens was determined by Charpy tests. The values of independent variables (effective strain, coefficient of friction) influence the value of the dependent variable, impact toughness. On the basis of training data, different prediction models for impact toughness were developed by GP. Only the best models, gained by genetic programming were presented in the paper. Accuracy of the best models was proved with the testing data set. The comparison between deviation of genetic model results and regression model results concerning the experimental results has showed that genetic models are more precise and more varied then regression models.
Keywords: metal forming, genetic programming, evolutionary computing, impact toughness, copper alloy, modelling
Published: 30.05.2012; Views: 1655; Downloads: 86
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76.
Razvoj mikromontažnega sistema za sestavo očal
Denis Trstenjak, 2012, undergraduate thesis

Abstract: V diplomski nalogi je predstavljen razvoj priprav za montažo oziroma lepljenje okrasnih kamnov proizvajalca Swarovski na okraske, ki so sestavni del nekaterih modelov očal v podje-tju Carrera Optyl Ormož. Moja naloga v podjetju je bila sodelovati pri razvoju priprav, ki omogočajo hitrejši nanos lepila v okraske in vstavljanje kamnov v ležišča, kar je do sedaj potekalo izključno ročno. V diplomski nalogi je predstavljen sistem, ki to omogoča z minimalnimi stroški, z namenom postati konkurenčen v primerjavi z ostalimi podjetji znotraj koncerna Safilo, in tako pripeljati delo v našo tovarno. Pri razvoju nam je bila v pomoč napredna orodjarna, programski paket Catia in stroj za hitro izdelavo prototipov. Rezultati razvoja priprav so izpolnili naša pričako-vanja.
Keywords: Proizvodnja, montaža, mikromontaža, roboti, doziranje, lepljenje
Published: 23.05.2012; Views: 1755; Downloads: 114
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77.
Izdelava prototipnih robotskih prijemal s CNC-stroji
Rok Merkač, 2012, undergraduate thesis

Abstract: Diploma vsebuje potek izdelave robotskega prijemala in njegovo sestavo iz aluminija. Opisani so postopki, ki so potrebni za izdelavo prijemala, in sicer 3D-modeliranje posameznih sestavnih delov, izdelava NC-kode in pozneje izdelava na CNC-strojih. Posamezni sestavni deli so bili eloksirani in sestavljeni s pomočjo ročne montaže. Med izdelavo je prišlo do številnih problemov, ki so pojasnjeni in za katere so predlagane rešitve.
Keywords: VRSTE PRIJEMAL, CNC IZDELAVA, ELOKSACIJA, MONTAŽA PRIJEMAL
Published: 23.05.2012; Views: 1733; Downloads: 146
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78.
Varnostne zračne blazine v sodobnih vozilih
Timi Fazliu, 2012, undergraduate thesis

Abstract: V diplomski nalogi so predstavljeni zgradba,novosti in delovanje sodobnih zračnih blazin. Varnostni sistemi se delijo na aktivne, ki delujejo ves čas in pasivne, ki delujejo le v primeru prometne nesreče. Najbolj znani pasivni varnostni sistemi so varnostni pasovi in varnostne zračne blazine. Nekaj prostora sem namenil tudi zgodovini. Proučil bom kako lahko varnostna naprava vpliva na človeka, kakšne posledice lahko pušča ter pomembnost zračnih blazin v osebnih vozilih.
Keywords: varnostne zračne blazine, sodobna vozila, napredne zračne blazine
Published: 23.05.2012; Views: 1999; Downloads: 415
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79.
Model inteligentnega CAD/CAM sistema za programiranje CNC obdelovalnih strojev
Simon Klančnik, 2012, dissertation

Abstract: Sodobni obdelovalni sistemi so visoko avtomatizirani, zahtevajo veliko fleksibilnost in težijo k popolni avtonomnosti. Ker je programiranje obdelovalnih strojev zelo kompleksen proces, ki ga sestavlja več med seboj odvisnih problemov, ga kljub velikim naporom do danes še ni uspelo avtomatizirati. Pregled raziskav je pokazal, da so do sedaj razviti sistemi zelo ozko omejeni in lahko strokovnjaku služijo le kot pripomoček, pri pripravi postopka obdelave. V disertaciji predlagamo samodejno programiranje CNC-obdelovalnih strojev s pomočjo umetne inteligence. Razvita inteligenca je sposobna, ne le delno, ampak v celoti, reševati kompleksen problem samodejnega programiranja obdelovalnih strojev. Sistem na podlagi CAD-modela izdelka samodejno, brez pomoči strokovnjaka, pripravi NC-program obdelave, in sicer tako, da je obdelava varna, pravilna, časovno učinkovita in hkrati zadosti določenim tehnološkim zahtevam obdelave. Inteligentni CAD/CAM-sistem za svoje delovanje uporablja skupinsko inteligenco, NSGA-II večkriterijsko optimizacijo in usmerjeno nevronsko mrežo, hkrati pa koristi prednosti ter moč informatizacije in tako s porazdeljeno arhitekturo dosega večjo učinkovitost pri celovitem reševanju tako kompleksnega problema. Sistem je sestavljen iz napovedovalnega in evalvacijskega modula. V napovedovalnem modulu umetna inteligenca predlaga rešitve, ki vsebujejo informacije o trajektorijah rezov, izbranih orodjih in predlaganih rezalnih parametrih. Evalvacijski modul, na podlagi razvitih simulacijskih modelov, oceni predlagane rešitve glede na geometrijski, tehnološki in časovni kriterij ter kriterij učinkovitosti obdelave. V okviru raziskave smo razvili diskreten in tudi zvezen simulacijski model, ki ga razviti sistem uporablja pri iskanju optimalne rešitve. Predlagani sistem je v splošnem primeren za različne vrste obdelav, v disertaciji pa se zaradi obsega dela pri testiranjih omejimo zgolj na rezkanje. Rezultati testiranj so potrdili, da je z uporabo metod umetne inteligence mogoče samodejno programirati obdelovalne stroje.
Keywords: skupinska inteligenca, optimizacija z rojem delcev, nevronske mreže, genetski algoritmi, NSGA-II optimizacija, CAD/CAM-sistem, NC-programiranje, API-vmesnik, CNC-obdelovalni stroj, inteligentni obdelovalni sistem, računalniška simulacija, večkriterijska optimizacija
Published: 12.04.2012; Views: 3776; Downloads: 510
.pdf Full text (18,28 MB)

80.
Tehnološke izboljšave pri proizvodnji darilne embalaže
Primož Lesjak, 2012, undergraduate thesis

Abstract: V diplomskem delu predstavljamo izdelavo darilne embalaže iz papirja, kartona in lepenke. Izbrana je bila embalaža za penino s pripadajočima kozarcema. V teoretičnem delu je na splošno predstavljena embalaža in njen pomen. Opisane so tudi vrste embalaž. Prav tako so tudi predstavljeni primarni in sekundarni materiali za izdelavo tovrstne embalaže. V eksperimentalnem delu prikazujemo ročno izdelano embalažo. V drugem delu pa opisujemo praktični potek izdelave škatle za penino in dva kozarca. V nadaljevanju je opisano CAD/CAM modeliranje darilne embalaže. V zadnjem delu diplome predlagamo tehnološke izboljšave pri proizvodnji darilne embalaže.
Keywords: proizvodnja darilne embalaže, papir, karton, lepenka, CAD/CAM, strojna oprema.
Published: 08.03.2012; Views: 1817; Downloads: 74
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