Mechanical properties of parts fabricated with inkjet 3D printing through efficient experimental design

To design and optimize parts for additive manufacturing (AM) processes it is necessary to understand their variations in geometric and mechanical properties. In this work, such variations of inkjet 3D printed structures are systematically investigated by analyzing parameters of the whole process. The aim is to determine and quantify the parameters that lead to the most accurate geometry and to the best mechanical properties. Using this understanding, it is possible to build accurate part models and optimize, fabricate and test them successfully. Significant impacts on the mechanical properties are found, in descending order, for the number of intersections between layers and nozzles orthogonal to the load-direction, the exposure time to ultraviolet light, the position on the printing table and the expiry date of the raw material. Nozzle blockage significantly affects the geometry and also the machine's warm-up time is an important factor. Minor effects are found for the storage time and the surface roughness is not affected by any factor. Since AM materials change rapidly and the characterization process will have to be repeated, it is shown how to fully exploit the Design of Experiments method to create a cost and time efficient design with a high statistical accuracy. (C) 2015 Elsevier Ltd. All rights reserved.