Additive Manufacturing of Isotropic NdFeB PPS Bonded Permanent Magnets

Abstract

Extrusion based additive manufacturing of polymer composite magnets can increase the solid loading volume fraction with greater mechanical force through the printing nozzle as compared to traditional injection molding process. About 63 vol% of isotropic NdFeB magnet powders were compounded with 37 vol% of polyphenylene sulfide and bonded permanent magnets were fabricated while using Big Area Additive Manufacturing without any degradation in magnetic properties. The polyphenylene sulfide bonded magnets have a tensile stress of 20 MPa, almost double than that of nylon bonded permanent magnets. Additively manufactured and surface-protective-resin coated bonded magnets meet the industrial stability criterion of up to 175 °C with a flux-loss of 2.35% over 1000 h. They also exhibit better corrosion resistance behavior when exposed to acidic (pH = 1.35) solution for 24 h and also annealed at 80 °C over 100 h (at 95% relative humidity) over without coated magnets. Thus, polyphenylene sulfide bonded, additively manufactured, protective resin coated bonded permanent magnets provide better thermal, mechanical, and magnetic properties.

A Review on Additive Manufacturing Possibilities for Electrical Machines

“…Employment of AM in production of electrical machines is a promising aspect offering various benefits over conventional manufacturing techniques, such as; realization of 3D-designs (including electrical, magnetic, mechanical and thermal considerations) [9], recyclable constructions [10] and optimal material utilization. Basic and standardized AM techniques for manufacturing processes have been described in [11,12] almost all of which have been used in manufacturing electrical machines or its parts, at various instances [13][14][15]. Among all the AM processes, selective laser melting (SLM), fused deposition modeling (FDM) and binder jet printing (BJP) technology are the ones shown to be most promising for the manufacturing of electrical machines [16].…”

“…Decreasing the use of rare-earth elements in magnet production has a positive effect on the cost and production diversity [57]. Through AM, isotropic or anisotropic properties can be modified/created by controlling the grain structure [15,58,59]. This yields better control over magnetic properties without relying much on rare-earth materials like Dy, Tb, Pr etc.…”

A Comprehensive Review of Additive Manufacturing in Construction of Electrical Machines

“…When reviewing the available literature related to AM of electrical machines, it is clear that the technology maturity is relatively low at the moment [11]- [36]. This is particularly evident in the context of active components of an electrical machine assembly like magnetic or winding materials, which frequently offer poorer physical properties, compared with the existing solutions which are commonly used in construction of electrical machines [11]- [36]. With that being said, the research and development has been progressing fast with new improved AM techniques and materials reported on, e.g.…”

“…It is the authors belief that successful deployment of AM in manufacture of electrical machines is just a matter of time. It is interesting to observe that the majority of work related to the AM of electrical machines is focused on the individual machine components and materials [11]- [36], though, some attempts have been made to introduce a more holistic approach, where multiple parts are fabricated using AM [47], [51].…”

“…It is important to note that other types of AM have also been successfully employed in fabrication of electrical machines, e.g. material jetting, material extrusion and sheet lamination [4], [36], [47]. Fig.…”