Aboratory sifter (Retsch) and sieved via 400 mesh (Retsch). Powders prepared this
Aboratory sifter (Retsch) and sieved through 400 mesh (Retsch). Powders prepared this way served as a filler for the preparation of a polymer-ceramic composite filament. Powder samples for physicochemical tests were labelled as follows, powders soon after etching Al2 O3 _1 and ZrO2 _1 and powders soon after etching and chemical surface modification, Al2 O3 _2 and ZrO2 _2. two.two. Filament Preparation To produce the polymer ceramic filaments, a twin-screw extruder for the compounding, along with a single screw extruder for the filament preparation, were made use of. To prevent hydrolysis, the PA-12 (VESTAMID PA12, Evonik) granulate was pre-dried at 50 C for ten h, alumina and zirconia powders have been dried at 150 C for 10 h. The molecular weight of PA-12 ranged from 9100 to 16,600 gmol-1 [39]. The EBVP 25/44D extruder from O.M.C. SRL (Saronno, Italy) was utilised for compounding. The ceramic powder plus the polymer granules have been dosed gravimetrically having a mass ratio of 30 ceramic powder to 70 polymer (PA). The CFs content material was determined experimentally based on trials. Contents greater than 30 triggered print high-quality degradation and clogging of the FDM print head. A doable solution to this dilemma was to use an FDM printing modification having a movable pistonMaterials 2021, 14,four ofthat regulated the pressure in the head outlet [40]. The mass throughput was four.two kg/h at one hundred rpm. The extruder temperature was selected above the melting temperature of PA and was 260 C in the extruder exit. Just after compounding, the polymer ceramic strand was cooled using a water bath then granulated. A single-screw extruder from DR. COLLIN GmbH (Ebersberg, Germany) was utilized for shaping. The mass throughput was three kg/h at 14 rpm. Immediately after extrusion, the polymer ceramic melt was pulled using a pull-off force, which depended around the crystallization degree of the carrier material. To set the pull-off force, filament diameters amongst 1.six and 1.8 mm were ensured, recorded working with a WIREMASTER plus the ODAC 18 XY laser head from Benidipine Membrane Transporter/Ion Channel Zumbach (Orpund, Switzerland). The material utilized for comparison in batch 4 was a commercially accessible white 1.75 mm eco PLA filament from 3DJAKE (Niceshops GmbH, Paldau, Austria). two.three. Filament Mechanical Testing Sample Preparation Initially, two geometric samples have been printed working with a PA-ZrO2 filament and an extruder temperature amongst 205 and 260 C with stepwise temperature increases of 5 C to assess the processable temperature variety necessary to obtain a GNF6702 Autophagy qualitative satisfactory surface good quality and interlayer bonding. Employing the exact same material, 30 samples, variety 1BA, with the EN ISO 527-2:2012 norm four mm thick were printed vertically at temperatures amongst 230 and 255 C with stepwise temperature increases of 5 C (batch 1), to figure out the optimal temperature for interlayer binding. The infill density of those tensile specimens was set to 90 to lessen instabilities during printing with the upper layers brought on by the higher sample aspect ratio. Both batches have been processed working with a industrial Ender three Pro printer from Creality(Creality, Shenzhen, China), which was converted for printing ceramics by replacing the extruder with the Micro Swiss Direct Drive Extruder (Creality, Shenzhen, China) to guarantee a stable feed price and print ceramic filaments with limited abrasion in the drive gears. To improve adhesion, the print bed was replaced with an Ultrabase glass print bed from Anycubic (Anycubic, Shenzhen, China). For the duration of the second step, batches 2 and three have been printed employing the optimized interlayer.