20.500.12556/RUL-139016 Eksperimentalno vrednotenje volumskega termičnega raztezanja poliuretana za izdelavo modelov, orodij in kalupov Experimental evaluation of volumetric thermal expansion of polyurethane for the production of models, tools and molds V strojništvu se poliuretan pogosto uporablja pri izdelavi preciznih prototipnih orodji, kalupov in modelov (kontrolnih naprav). Ti izdelki imajo visoke zahteve za dimenzijsko točnost. Termični raztezek poliuretana je lahko razlog, da izdelki postanejo dimenzijsko neustrezni. S CNC strojem smo izdelali, s CMM strojem pa eksperimentalno določili spremembo volumna izbranih testnih teles iz poliuretana zaradi termičnega raztezanja. Podali smo oceno vpliva temperature na dimenzijsko točnost izdelkov. Ugotovljeno je bilo, da ima temperatura oz. njena sprememba velik vpliv na dimenzijsko ustreznost precizno izdelanih izdelkov iz poliuretana, kar pa se v praksi prepogosto zanemari. Izdelava testnega volumna s postopkom lepljenja več enako velikih kosov poliuretana z dvokomponentnim lepilom ima vpliv na končni termični raztezek tako narejenega telesa, nima pa vpliva na njegov temperaturni odziv po času. Za izdelke, izdelane iz homogenega kosa poliuretana, velja predpostavka, da za koeficient volumskega termičnega raztezka lahko vzamemo trikratno vrednost linearnega termičnega raztezka (ß ? 3?). In mechanical engineering, polyurethane is often used in the production of precise prototype tools, molds and models (control devices). These products have high requirements for dimensional accuracy. Thermal expansion of polyurethane can be the reason that products become dimensionally inadequate. Polyurethane test bodies were produced with the CNC machine. The change in body volume due to thermal expansion was determined experimentally utilizing the CMM machine. The assessment of the temperature influence on the dimensional accuracy of products was given. It has been shown that temperature, or its variation, has a major influence on the dimensional suitability of precision-manufactured polyurethane products, which is too often neglected in practice. The production of a test volume by bonding several equal sized pieces of polyurethane with a two-component adhesive has an effect on the final thermal expansion of the body so produced, but no effect on its temperature response over time. For products made from a homogeneous piece of polyurethane, it is assumed that the coefficient of volumetric thermal expansion can be taken to be three times the value of the linear thermal expansion (β ⡈ 3α). temperatura termično raztezanje snovi volumski raztezek trdnin poliuretan meritve temperature thermal expansion of matter volumetric expansion of solids polyurethane measurements true false false [M. Brus] Slovenski jezik Angleški jezik Diplomsko delo/naloga 2022-08-29 08:21:03 2022-08-29 08:21:05 2023-11-10 13:05:30 0000-00-00 00:00:00 2022 0 Ljubljana 0 XXII, [58] str. 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 536.413:678.664(043.2) 242645 120310787 17144.pdf 17144.pdf 1 27BA5A59F7BCA51EA89B701B2BBAB226 9de45be31c5a1c209341e353793c4d7dadde3f94ae2f5eda906cfdc25c365c02 bb733858-2762-11ed-92af-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=159521 Fakulteta za strojništvo 0 0 0