FEATURE / LASER-SINTERING PROCESS Figure 4. Simplified test setup for investigating the influencing parameters. Figure 5. Used nozzle geometries (left) and experiments carried out (right). underneath the platform. Figure 4 (left) shows the setup without lateral and upper insulation. The heat input of the moving nozzle caused a HAZ into the already sintered specimen with the size of 15mm x 15mm x 2.5mm. The components were prefabricated by Sintratec PA12 using a Sintratec KIT system. In order to obtain a process atmosphere as close as possible to the laser sintering process, they were placed on the heated building platform of the test setup. The heating mat mounted to the building platform heats the specimens to approx. 175°C. This temperature was maintained for 15min so that the sample is completely heated through. The nozzle was then moved over the component with the set parameters, the specimen removed and the nozzle moved back to its starting position. Influence Analysis Different nozzle geometries and sizes were selected to analyse the geometry influence of the nozzle. The nozzle feed rate, the distance between the nozzle as well as the nozzle temperature were selected as factors for investigating the influencing parameters during fibre integration. According to Figure 5 (left), planar and concave surfaces were used as nozzle geometries. The planar nozzles were divided into Ø6mm (a), Ø2.2mm (b) and an E3D-V6 nozzle (d) with Ø1.25mm outer diameter. The concave nozzle (c) was manufactured with an outer diameter of Ø6mm and a curvature radius of 2.75mm. For the influence analysis of the HAZ, the tests listed in Figure 5 (right) were carried out. This allows the evaluation of the influences for the individual nozzles but also the comparison between them. The factor levels of these test series were determined by preliminary tests. The target variables are the width and depth of the HAZ. A stereo microscope with Axio Vision SE64 software Figure 6. Novel laser sintering machine with fibre integration unit. 30 | SAMPE JOURNAL | NOVEMBER/DECEMBER 2021 www. sampe.orghttp://www.sampe.org