Fabrication of Non-Contact Magnetic Screws by Additive Manufacturing

Magnetic screws are characterized by their noncontact features, thus eliminating the disadvantage of friction loss inherent in traditional screws. Some applications require spiral-shaped screws; however, commercially available magnets are rarely spiral in shape. To obtain spiral-shaped screws, manufactures require molds or the magnets are spliced to desired shape. Unfortunately, these two fabrication processes both have drawbacks, which include, discontinuity in the magnetic flux, high cost, and reduced efficiency. This article therefore presents alternative approach that involves the design and fabrication of spiral magnetic screws via 3-D printing with magnetic materials. The prototypes were fabricated using two 3-D printing techniques, pellet deposit melting (PDM) and hybrid soft magnet selective laser melting (SLM). Finite element method is adopted to simulate and validate the fabricated magnetic screw. Experiment results, using the PDM fabricated magnets and the hybrid soft magnet SLM combined with commercial sintered NdFeB magnet are also provided, along with, verification of the design characteristics and the simulation results.