This master thesis was written in the frame of the FFG-project „3D Print Technologies - New additive production technologies for the wood industry“ (short title "3D - Wood", project no. 850754). In this project, alternatives to conventional wood processing for the wood industry were explored. A possible approach is the use of additive manufacturing methods in combination with wood-plastic composites. The shaping in the wood industry is usually done by machining raw work pieces by subtractive removing material. In contrast to additive manufacturing, where material is added layer by layer during the production process of the part. This results in a very efficient use of the applied materials and a great deal of design freedom. In addition, the manufacturing process of parts, which normally requires several steps, can be automated in a simplified step. As part of the project for this master thesis test pieces were produced by using the material-extrusion process. These were printed directly on wood substrate surfaces, which then were tested by a lift-off test. The purpose was - by combining different filaments and differently pretreated or non-pretreated substrate surfaces to achieve lift-off values greater than those specified in standard EN 312 for interior furnishings in dry sections. It was found that the developed adhesion forces on non-pretreated substrate surfaces are too low to ensure a reliable application in the industry. By the usage of bonding agents it was possible to achieve partially significantly higher values than those required by the EN 312 standard and therefore a potential for industrial applications could be proved. Furthermore, the used materials were extensively investigated thermally and rheologically. This served on the one hand to find optimal processing conditions and on the other hand to perform flow simulations. Based on the simulations, it was evaluated if 3D printing is principally possible from a flow-technical point of view and if the filaments can be processed on the used machine. For this purpose, the fill level of the filaments, the volume flow and the nozzle diameter were varied and it could be shown that a wide field of application can be covered. In order to evaluate the model, the meshing, the simplifications, the mathematical descriptions of the material data models, etc. extensive investigations with the help of a high pressure capillary rheometer were done. This was extremely expedient for the subsequent simulations of the actual extruder which should be investigated.