The design of pipe thread rolling rollers

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

Cilj istraživanja bio je utvrditi integritet površine dijelova proizvedenih klasičnim postupkom obrade odvajanjem čestica, tokarenjem i aditivnim postupkom taložnog očvršćivanja (tzv. FDM postupak). Pri analizi površine korištene su suvremene metrološke metode auto korelacije i gradijentne razdiobe. Površinska 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

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

Additive Manufacturing of Medical Models - Applications in Rhinology

In the paper we are introducing guidelines and suggestions for use of 3D image processing SW in head pathology diagnostic and procedures for obtaining physical medical model by additive manufacturing/rapid prototyping techniques, bearing in mind the improvement of surgery performance, its maximum security and faster postoperative recovery of patients. This approach has been verified in two case reports. In the treatment we used intelligent classifier-schemes for abnormal patterns using computer-based system for 3D-virtual and endoscopic assistance in rhinology, with appropriate visualization of anatomy and pathology within the nose, paranasal sinuses, and scull base area

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

U kontekstu opće krize i opadanja političke potpore socijaldemokraciji članak‎ se usredotočuje na socijaldemokraciju u Hrvatskoj i na razinu izborne potražnje.‎ Nastojeći pridonijeti razumijevanju stanja socijaldemokracije u Hrvatskoj, ‎analizira se odnos ideološkog samoidentificiranja birača i njihovih stranačkih‎ preferencija na primjeru socijaldemokracije i glasovanja za SDP. Na‎ temelju podataka dobivenih terenskim anketnim istraživanjima u razdoblju ‎od 1999. do 2020. godine nastoje se identificirati faktori koji utječu na to da ‎socijaldemokratski birači glasuju, odnosno ne glasuju za stranku koja tu političku ‎ideologiju predstavlja – SDP. U radu se testira generalizirani linearni‎ mješoviti model u kojemu se godine anketiranja tretiraju kao slučajni efekti.‎ Kao značajni faktori koji objašnjavaju zašto neki socijaldemokrati glasuju za‎ SDP, a neki ne pokazuju se samoidentifikacija na ljestvici lijevo-desno te stav‎ o pobačaju, pri čemu su SDP-ovi birači koji se nalaze na ljevijim pozicijama‎s kloniji podržavati slobodno odlučivanje žene o prekidu trudnoće od drugih‎ socijaldemokratskih birača. Slučajni efekt godine anketiranja pokazuje nisku ‎varijabilnost, no pojačavajući utjecaj na fiksni efekt vidljiv je za 2003. i 2012.‎ godinu kada dolazi do razilaženja, odnosno okupljanja socijaldemokratskih‎ birača oko SDP-a. Model upućuje na važnost ideološke samoidentifikacije za ‎biračku orijentaciju čak i među biračima istoga ideološkog predznaka.‎The article focuses on social democracy in Croatia and on electoral demand ‎in the context of the general crisis and declining political support for social‎democracy. The paper seeks to contribute to the understanding of the state of ‎social democracy in Croatia, by examining the relationship between voter ideological ‎self-identification and party preferences regarding social democracy ‎and voting for the SDP. The analysis uses data obtained through field surveys ‎from 1999 to 2020, to identify factors that influence social democratic voters‎ to vote for the party that represents this political ideology – the SDP. The paper ‎tests a generalized linear mixed model in which survey years are treated as random‎ effects. Self-identification on the left-right scale, as well as the attitude on ‎abortion are found to be significant factors explaining why some social democrats ‎vote for the SDP and others do not, with SDP voters leaning towards more ‎left-wing positions and being more likely to support a woman’s free choice on‎ abortion when compared to other social democratic voters. The random effect‎ of survey years has shown low variability, but the amplification of the impact ‎of the fixed effects is evident for 2003 and 2012, where we can see fragmentation ‎and consolidation, respectively, of social democratic voter support for SDP.‎ The model points to the importance of ideological self-identification for voter‎ orientation even among voters from the same ideological camp.

Teorijske osnove proizvodnje polimernih tvorevina

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 sveučilišnom preddiplomskom studiju strojarstva na Strojarskom fakultetu u Slavonskom Brodu i sveučilišnom preddiplomskom studiju strojarstva Fakulteta strojarstva i brodogradnje u Zagrebu. Opseg izlaganja u udžbeniku znatno nadmašuje 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

The essence and applications of machine vision

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 najčešće zahtijevaju uporabu dodatnog izlazno/ulaznog sučelja i računalnih mreža za prijenos podataka generiranih od strane drugih procesnih komponenti, primjerice robota, manipulatora itd. Jedan od najčešćih primjena strojne vizije jest kontrola kvalitete proizvoda, primjerice mikroprocesora, automobila, hrane i farmaceutskih proizvoda. Sustavi strojne vizije učestalo se upotrebljavaju za rješavanje 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 današnje 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