Characteristics of 3D printed elements depending on the proportion of wood in plastomer

V raziskavi smo preskušali materiale za tiskanje iz PLA polimera z dodatkom lesnega prahu. Uporabili smo pripravljene filamente z vsebnostjo 10 %, 20 %, 30 %, 40 % in 50 % lesnega prahu glede na maso filamenta. S 3D tiskalnikom Zortrax M200 smo iz vsakega materiala natisnili 12 preizkušancev, ki smo jih po sušenju in tehtanju kondicionirali v komorah z različno vlažnostjo (relativna zračna vlažnost 33 %, 65 % in 87 %), ob tem pa spremljali spremembe dimenzij in mase. Po končanem kondicioniranju smo izmerili tudi upogibno trdnost in trdoto natisnjenih delov. Ugotovili smo, da je masa in vlažnost preskušancev naraščala ob kondicioniranju v vlažni klimi, kar pomeni, da les v filamentu vpliva na lastnosti natisnjenega izdelka. S preizkušanjem smo ugotovili, da upogibna trdnost in trdota natisnjenih delov padata z deležem lesnega prahu v filamentu. Vzrokov je predvidoma več: majhni delci lesa delujejo predvsem kot polnilo, pri tiskanju pride do nastanka praznih prostorov v strukturi in slabše zlepljenosti slojev, saj so imeli filamenti z lesnim deležem neenakomeren premer, kar povzroči neenakomerno ekstrudiranje materiala skozi tiskalno šobo ter pri večji vsebnosti lesnega prahu prihaja do mašenja tiskalne šobe.In this study, we tested printing materials from PLA thermoplastic with the addition of wood dust. We used filaments with a content of 10 %, 20 %, 30 %, 40 % and 50 % of wood dust based on the weight of filament. With 3D printer Zortrax M200 we printed 12 samples from each material, which were conditioned after drying and weighing in chambers with varying humidity (relative humidity 33 %, 65 % and 87 %), and measured changes in dimensions and mass. The bending strength and hardness of the printed parts were measured after conditioning. We found that the mass/moisture content of specimens increased during conditioning in a humid climate, which means that the content of wood in the filament affects the properties of the printed product. By testing, we found that the bending strength and hardness of printed parts are decreasing with the proportion of wood dust in the filament. There are several reasons for this: small wood particles act primarily as a filler, during printing several empty spaces and poor adhesion between layers occurs due to irregular diameter of manufactured filaments with wood particles, which causes uneven extrusion of the material through the print nozzle and with higher content of wood dust we get more nozzle clogging