62 research outputs found

    The design of pipe thread rolling rollers

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    Prezentirana je analiza distribucije tolerancije kod valjanja cijevnog navoja s valjcima identičnog polumjera zaobljenja vrha navoja. Razrađeni su teorijski odnosi i metodologija za računanje promjera utiskivanja navoja s pretpostavljenom distribucijom tolerancije utiskivanja koje je mjereno pomoću istisnutog volumena materijala. Dani su ilustrirani primjeri razrađenih odnosa.The analysis of the allowance distribution in pipe thread rolling with rollers of the identical thread crest rounding radius has been presented. Theoretical relationships and methodology for computing the embossing thread diameter with the assumed distribution of the embossing allowance as measured by the displaced material volume have been elaborated. Examples illustrated elaborated relationships have been given

    Experimental analysis of surface roughness and surface texture of machined and fused deposition modelled parts

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    Cilj istraživanja bio je utvrditi integritet povrÅ”ine dijelova proizvedenih klasičnim postupkom obrade odvajanjem čestica, tokarenjem i aditivnim postupkom taložnog očvrŔćivanja (tzv. FDM postupak). Pri analizi povrÅ”ine koriÅ”tene su suvremene metroloÅ”ke metode auto korelacije i gradijentne razdiobe. PovrÅ”inska tekstura analizirana je pomoću Infinite Focus Measurement Machine (IFM) uređaja. Studija je provedena u stvarnom proizvodnom pogonu tijekom prototipne izrade novih proizvoda.The objective of the investigation was to identify surface integrity of machined parts by turning and by Fused Deposition Modelling (FDM) additive method produced ones. Surface analysis was made by using novel metrology methods: auto correlation and gradient distribution. An Infinite Focus Measurement Machine (IFM) was used for the surface texture analysis. The study was performed within a production facility during the prototyping process of new products

    Research of Protective Coatings Application on Polymer Formulations Made by Additive Technology

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    Injection molding of polymer moldings has proven to be a fast way of making products for medium and high series production for many years. In order to produce a quality product, all stages of the process must be under control (tools, materials, injection molding machine, etc.). In the last two decades, additive technology for the production of prototypes and, more recently, finished products has been developing intensively. The biggest disadvantage of additive technology is the limited choice of polymer materials and different mechanical properties of products compared to products produced by injection molding technology. Making a mold for the injection molding process is time consuming and expensive, and for smaller batches, an unprofitable process. By making molds for injection molding with additive technology, we accelerate the process of production of finished products. One of the disadvantages of making molds in this way is their durability. In order to increase the durability of the mold, the area of coating application will be investigated. The research was conducted as part of the application for a doctoral thesis. The paper will be divided into three key sections. The first part of the paper will explain the research conducted so far. In the second part, the examination of the surface parameters that are necessary for us to obtain the connection between the additive material and the coating will be presented. Taking into consideration the first two units, the third unit will explain: the selection of the experiment plan, input factors, output factors as well as the method of conducting the experiment

    Micro/Nano Material Processing

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    Social Democracy in Croatia: Ideological Self-Identification and Voter Preferences

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    U kontekstu opće krize i opadanja političke potpore socijaldemokraciji članakā€Ž se usredotočuje na socijaldemokraciju u Hrvatskoj i na razinu izborne potražnje.ā€Ž Nastojeći pridonijeti razumijevanju stanja socijaldemokracije u Hrvatskoj, ā€Žanalizira se odnos ideoloÅ”kog samoidentificiranja birača i njihovih stranačkihā€Ž preferencija na primjeru socijaldemokracije i glasovanja za SDP. Naā€Ž temelju podataka dobivenih terenskim anketnim istraživanjima u razdoblju ā€Žod 1999. do 2020. godine nastoje se identificirati faktori koji utječu na to da ā€Žsocijaldemokratski birači glasuju, odnosno ne glasuju za stranku koja tu političku ā€Žideologiju predstavlja ā€“ SDP. U radu se testira generalizirani linearniā€Ž mjeÅ”oviti model u kojemu se godine anketiranja tretiraju kao slučajni efekti.ā€Ž Kao značajni faktori koji objaÅ”njavaju zaÅ”to neki socijaldemokrati glasuju zaā€Ž SDP, a neki ne pokazuju se samoidentifikacija na ljestvici lijevo-desno te stavā€Ž o pobačaju, pri čemu su SDP-ovi birači koji se nalaze na ljevijim pozicijamaā€Žs kloniji podržavati slobodno odlučivanje žene o prekidu trudnoće od drugihā€Ž socijaldemokratskih birača. Slučajni efekt godine anketiranja pokazuje nisku ā€Žvarijabilnost, no pojačavajući utjecaj na fiksni efekt vidljiv je za 2003. i 2012.ā€Ž godinu kada dolazi do razilaženja, odnosno okupljanja socijaldemokratskihā€Ž birača oko SDP-a. Model upućuje na važnost ideoloÅ”ke samoidentifikacije za ā€Žbiračku orijentaciju čak i među biračima istoga ideoloÅ”kog predznaka.ā€ŽThe article focuses on social democracy in Croatia and on electoral demand ā€Žin the context of the general crisis and declining political support for socialā€Ždemocracy. The paper seeks to contribute to the understanding of the state of ā€Žsocial democracy in Croatia, by examining the relationship between voter ideological ā€Žself-identification and party preferences regarding social democracy ā€Žand voting for the SDP. The analysis uses data obtained through field surveys ā€Žfrom 1999 to 2020, to identify factors that influence social democratic votersā€Ž to vote for the party that represents this political ideology ā€“ the SDP. The paper ā€Žtests a generalized linear mixed model in which survey years are treated as randomā€Ž effects. Self-identification on the left-right scale, as well as the attitude on ā€Žabortion are found to be significant factors explaining why some social democrats ā€Žvote for the SDP and others do not, with SDP voters leaning towards more ā€Žleft-wing positions and being more likely to support a womanā€™s free choice onā€Ž abortion when compared to other social democratic voters. The random effectā€Ž of survey years has shown low variability, but the amplification of the impact ā€Žof the fixed effects is evident for 2003 and 2012, where we can see fragmentation ā€Žand consolidation, respectively, of social democratic voter support for SDP.ā€Ž The model points to the importance of ideological self-identification for voterā€Ž orientation even among voters from the same ideological camp.

    Prigodom 15 godina izdavanja

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    Teorijske osnove proizvodnje polimernih tvorevina

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    Udžbenik je osnovna literatura za predmete Preradba polimernih materijala, Proizvodnja polimernih tvorevina, Ljevarstvo i prerada polimera i Proizvodni postupci, koje autori kao obvezne kolegije predaju na sveučiliÅ”nom preddiplomskom studiju strojarstva na Strojarskom fakultetu u Slavonskom Brodu i sveučiliÅ”nom preddiplomskom studiju strojarstva Fakulteta strojarstva i brodogradnje u Zagrebu. Opseg izlaganja u udžbeniku znatno nadmaÅ”uje opseg tih kolegija, pa je udžbenik primjeren i za produbljeno proučavanje preradbe polimera na poslijediplomskim studijima odgovarajućih tehničkih fakulteta. Pored toga, udžbenik je kao pretežita ili dopunska literatura primjeren za čitav niz drugih kolegija iz područja preradbe polimera, tehnologija i materijala koji u svom sadržaju uključuju razne aspekte bavljenja polimernim materijalima i postupcima njihove preradbe u gotove proizvode, a u čijem izvođenju sudjeluju autori

    Joining of Plastics and Composites

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    The essence and applications of machine vision

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    Pojam strojne vizije (vizijskih sustava) obuhvaća industrijsku primjenu računalnih vizijskih sustava. Dok je računalna vizija usmjerena uglavnom na obradu slikovnih zapisa na hardverskoj razini, sustavi strojne vizije najčeŔće zahtijevaju uporabu dodatnog izlazno/ulaznog sučelja i računalnih mreža za prijenos podataka generiranih od strane drugih procesnih komponenti, primjerice robota, manipulatora itd. Jedan od najčeŔćih primjena strojne vizije jest kontrola kvalitete proizvoda, primjerice mikroprocesora, automobila, hrane i farmaceutskih proizvoda. Sustavi strojne vizije učestalo se upotrebljavaju za rjeÅ”avanje problema industrijske kontrole, te omogućuju potpunu automatizaciju procesa i povećanje pouzdanosti i učinkovitosti. Takvi sustavi rabe digitalne fotoaparate, kamere i odgovarajući softver za obradu slikovnih zapisa kako kod ručne, tako i kod automatske kontrole na proizvodnoj liniji. U radu su opisana temeljna načela obrade slikovnih zapisa, dijelovi sustava i danaÅ”nje mogućnosti primjene sustava strojne vizualizacije.Machine vision (system vision) comprises using computer vision in industry. While computer vision is focused mainly on image processing at the level of hardware, machine vision most often requires the use of additional hardware I/O (input/output) and computer networks to transmit information generated by the other process components, such as a robot arm. One of the most common applications of machine vision is inspection of the products such as microprocessors, cars, food and pharmaceuticals. Machine vision systems are used increasingly to solve problems of industrial inspection, allowing for complete automation of the inspection process and to increase its accuracy and efficiency. In the case of manual inspection on the production line as well as in the case of application of machine vision systems, digital cameras, smart cameras and image processing software have been used. This paper presents the principle of image processing, the components of the system and possible applications of machine vision in the present
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