Glajenje površin tiskanih termoplastičnih predmetov s polimernimi premazi

Namen diplomskega dela je bilo testiranje sposobnosti polimernih premazov pri glajenju površin 3D predmetov natisnjenih, s tehnologijo ekstrudiranja termoplastičnih materialov. Pri tem smo se osredotočili na iskanje ustreznega ravnotežja med stopnjo gladkosti površine, ohranjanjem detajlov ter časom tiska. Upoštevali smo tudi karakteristike premaza, kot so enostavnost nanosa, oprijemljivost, hlapnost topil in čas sušenja. Začeli smo z modeliranjem predmetov, ki so vsebovali bistvene elemente za testiranje navedenih lastnosti v programu Blender. Kot končni test smo zmodelirali še figuro za namizno igro, kar je predstavljalo test uporabe metode na praktičnem predmetu. Predmete smo izvozili v format .stl in pripravili za tisk v programu Slic3r Prusa Edition. Nato smo določili parametre tiska in predmete natisnili pri šestih različnih debelinah nanosa termoplasta, pri vsaki debelini pet različic. Od teh pet različic je bila ena namenjena kontroli, dve smo premazali s poliakrilnim in dve s poliuretanskim premazom. Za vsak premaz smo nato en predmet še dodatno presprejali z univerzalnim temeljnim lakom kot pripravo na barvanje. Za oceno rezultatov smo uporabili dva pristopa: slikovno analizo in merjenje adhezije. Predmete, oblikovane izključno za testiranje, smo po premazovanju fotografirali s stereo-mikroskopom Leica S9i, nato pa opravili slikovno analizo. Merjenje adhezije smo opravili z merilcem BYK Byko-cut universal ter določili stopnjo adhezije z vizualno oceno. Ugotovili smo, da glajenje s poliuretanskim premazom izboljša gladkost površine predmetov na nivo več stopenj višje natančnosti tiska. Njegova učinkovitost se začne manjšati pri slojih termoplasta, ki so debelejši od 0,20 mm, vendar je površina še zmeraj zglajena vsaj na nivo tiska debeline 0,10 mm. Poliakrilni premaz se je izkazal slabše zaradi velike izgube volumna med sušenjem, vendar je še zmeraj nekoliko izboljšal gladkost površine. V obeh primerih je prekrivanje z univerzalnim temeljnim lakom še dodatno izboljšalo stopnjo glajenja, glavna prednost pa je bila povečana adhezija in odpornost na obrabo. The purpose of this work was to test the capabilities of polymer coatings in smoothing objects, printed with the use of material extrusion technology. Our focus was on finding the optimal balance between surface smoothness, retention of detail and printing time. We also took into account the characteristics of the coating material, such as ease of application, adhesion, solvent volatility and drying time. We started by designing objects, which contained key elements for testing the afore mentioned properties, in Blender. As the final test, we also chose a tabletop game figurine, as a test of practical applicability of this method. We exported the objects in .stl format, and prepared them for printing in Slic3r Prusa Edition. After finding appropriate printing settings, we printed the objects at six different layer thicknesses, five copies for each thickness. Of these five copies, one was kept as a control, two were coated with a polyacrylic and two with a polyurethane coating. For each coating, we additionally sprayed one object with a universal base as a preparation for colouring. We decided on two approaches to evaluate the results: image analysis and measuring of adhesion. Objects designed purely for testing were photographed under a Leica S9i stereo-microscope, after which we performed image analysis on the captured material. We conducted adhesion testing with a BYK Byko-cut universal measurement tool and ascertained the level of adhesion with a visual evaluation. As part of the research, we found that smoothing with the polyurethane coating improves the surface smoothness of objects to that of several levels higher print precision. Its effectiveness begins to decrease with layers thicker than 0,20 mm, however the surface is still at least as smooth as if printed at 0,10 mm layer thickness. The polyacrylic coating fared worse, mostly due to losing a large portion of its volume during drying, however it still managed to improve surface smoothness to a lesser extent. In both cases, additional coating with the universal base has further improved surface smoothing, but the main advantage turned out to be the increased adhesion and wear resistance.