20.500.12556/RUL-109218 Optimizacija konstrukcije spojnika iz polimernega materiala po kriteriju lastne cene Optimisation of joint part design, made of polymer material, by cost criterion Spojnik iz termoplastičnega materiala, ki se vgrajuje v lesene plošče, je bil zaradi deformacij sredinske zareze konstrukcijsko optimiziran z dodatkom rebra. S pomočjo simulacije smo ugotovili, da dodano rebro neţeleno razpiranje v osrednjem delu razpolovili, na skrajnih koncih zareze pa ob obremenitvi povzroči dodaten stisk. Tako ob montaţi prekrivnega elementa na spojnik zareza zagotavlja tesnejši ujem. Sledilo je raziskovanje nastavitev parametrov injekcijskega brizganja, ki bi ob kratkih taktih dajali čim boljše rezultate. Predpostavili smo, da bo skrajšan cikel brizganja zniţal lastno ceno izdelka. Cilj je pokriti stroške, povezane z investicijo v orodje. S Taguchijevo metodo smo za ta namen načrtovali eksperiment, pri katerem lahko preučimo odziv procesa na tri najbolj vplivne parametre. Izbrani nastavljeni parametri za preizkus so temperatura orodja, čas naknadnega pritiska in čas ohlajanja. Za vrednotenje odziva smo opazovali 3 ciljne funkcije, in sicer estetiko površin, maso in dimenzijsko stabilnost izdelka. Iz rezultatov smo ugotovili, da višja temperatura orodja ugodno vpliva na estetiko površin. Masa in dimenzijska stabilnost sta se v mejah eksperimentalnih nastavitev izkazali za nespremenljivi. Proces brizganja je v mejah sprememb nastavitev robusten. Z eksperimentom smo tako ugotovili, da lahko obstoječi takt proizvodnje 20s brez teţav skrajšamo za 2 sekundi. Sledilo je računanje nove lastne cene pri krajšem ciklu brizganja. Nova lastna cena po spremembi orodja in krajšanju cikla se je kljub investiciji v orodje in dodatni masi izdelka izkazala za niţjo. Skrajšanje brizgalnega cikla za dve sekundi pri delu v treh izmenah v teoriji pomeni povprečen prihranek 1168 € na milijon proizvedenih kosov. Zaradi dokazane robustnosti procesa je z morebitnim nadaljnjim delom na tem primeru moţno dodatno krajšanje časa brizgalnega cikla. Plastic joint part, used in wooden panels, was detailed with another construction rib due to expanding deformation of groove used for tight anchoring. With help of simulation tools, we have proven, that design change managed to reduce unwanted expanding for about 50% in the middle section and also positively affected narrowing at the ends of the groove. Construction rib effectively ensures tight fit. Following part of thesis researched options for injection moulding process optimization. Ideally we want to achieve short cycles with perfect output. We suspect, that shortening of moulding cycle will reduce manufacturing cost. We expect to cover costs of design change. For that manner, we designed experiment with help of Taguchi’s methods. Experiment was designed to test the output change for three factors. Mould temperature, backing pressure time and cooling time. During the experiment we monitored process outputs like surface aesthetics, mass and dimensional stability. Within borders of experimental settings, it was proved, that higher mould temperature positively affects surface aesthetics. Mass and Dimension of product did not change. Moulding process was proved robust within experimental settings. With that in mind we managed to shorten existing moulding cycle time of 20 seconds for 2 seconds. Calculation showed, that with shortening of moulding cycle managed for 2 seconds cost dropped below the one, calculated before investment in design change. For average 3 shift work, we can save about 1168€ per million pieces. Considering fact, that process was proven to be robust, we can think about additional cycle shortening in near future with same methods. Polimerni materiali Injekcijsko brizganje Načrtovanje eksperimentov Simulacije Optimizacija Lastna cena Polymer materials Injection moulding Design of experiments Simulations Optimization Cost true false false [A. Durjava] Slovenski jezik Angleški jezik Zaključna naloga 2019-08-28 07:45:09 2019-08-28 07:45:23 2022-08-21 03:40:43 0000-00-00 00:00:00 2019 0 Ljubljana 0 XVII, 57 f. 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 678.027.74:62-44:658.5(043.2) 215183 16790555 3791.pdf 3791.pdf 1 D3DDDC67F752948930C17EFA0ED2B026 92a98b6865412c017525aa6c38890a6892d1e864aa6c5d3f10ad86bdfde04bd4 ce6bb1f5-a1b6-11eb-a523-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=120729 Fakulteta za strojništvo 0 0 0