Investigation of a Magnetic Field-Assisted Digital-Light-Processing Stereolithography for Functionally Graded Materials

Abstract Stereolithography (SLA) is one of the most efficient additive manufacturing (AM) methods in terms of dimensional resolution and accuracy. The use of multiple or functionally graded materials in this process can broaden the design space for applications such as sensors and biomedical implants. However, it is still challenging to fabricate such materials using SLA. In this study, we propose a method for fabrication of functionally graded materials with embedded magnetic particles using digital-light-processing SLA in a single step. Magnetite (Fe 3 O 4 ) particles with an approximate diameter of 300 nm were mixed with a diluted photocurable resin, and used in fabrication of the samples. A digital-light-processing SLA printer was modified to allow integration of a magnet holder above the print bed. Magnet holders with three different configurations of magnets were built and used to fabricate parts with controlled distribution of magnetic particles. Several parts have been printed and characterized by evaluating the concentration of ferromagnetic particles in different regions based on image analysis. The results of this study show that field assisted digital-light-processing SLA can be used to fabricate functionally graded materials with embedded magnetite particles. The resulting concentration of the particles depends on the strength and surface area of the magnets, and the distance between the magnets and the print bed. Experimental results are also used to verify a Finite Element model, which is developed to understand the effect of magnet location on particle concentration. The feasibility of the proposed process has been verified and this process can be used in additive manufacturing of magnetic field-responsive smart polymeric structures.