A. Shen, X. Peng, C.P. Bailey, A.W.K. Ma, S. Dardona
University of Connecticut,
Keywords: Magnet, 3D Printing, Rheology
Summary:Today, almost all commercial magnet manufacturers are using the conventional production method based on magnetic powder compaction and sintering. Alternatively, magnetic powder may be embedded directly within a polymer to produce “polymer-bonded magnets”. The latter method of magnet production has recently gained popularity because of the design freedom in terms of shapes and magnetizing structures. Compared to the conventional sintering process, the maximum energy product (BH)max of polymer-bonded magnets is generally lower. However, the fabrication of polymer-bonded magnets does not require high temperature sintering and thus reduces the associated costs and shortens the processing time. A new additive manufacturing method coined “UV-assisted direct write” (UVADW) has been developed to produce polymer-bonded magnets at room temperature . The UVADW method involves mixing magnetic powder (Nd-Fe-B) with a photo-curable binder to create an ink, which is then extruded through a nozzle and deposited onto a substrate. Understanding the ink rheology is critical to ensuring the printability and the shape fidelity of the printed structures. Parameters explored include the shape and polydispersity of the Nd-Fe-B particles with the ultimate goal to maximize the loading of the magnetic particles and consequently the magnetic performance.  A. Shen, C. P. Bailey, A. W. K. Ma, S. Dardona. UV-assisted direct write of polymer-bonded magnets. Journal of Magnetism and Magnetic Materials, 462, 220-225 (2018).