Additive manufacturing of wood composite parts by individual layer fabrication - influence of process parameters on product properties

Individual Layer Fabrication (ILF) is a novel additive manufacturing process that was developed to create objects with high wood content and high mechanical strength. Here, thin and individually contoured wood composite panels are created via Binder Jetting and subsequent mechanical pressing. Like in Sheet Lamination, these panels are then laminated onto each other to create a three-dimensional object. With wood contents (more than 85 mass percent) and mechanical properties (more than 30 MPa flexural strength) on par with other engineered wood products like particle boards and plywood, the produced objects are well suited for the construction and furniture industry. To gain a deeper understanding of the process, the influence of processing parameters on the geometric and mechanical properties of the finished objects were investigated. As process parameters the amounts of adhesive and the pressing forces for both panel production and lamination were selected. It was discovered that the interaction between the amount of adhesive and the pressure used to produce the panels is highly relevant for the geometric properties. The three core mechanisms that are responsible for the mechanical properties of produced parts were identified and can be ranked in the following order: 1) the amount of adhesive in the panels binding the particles, 2) the density of the panels, 3) the amount of adhesive for laminating the panels.