A Toroid Designed to Have a Self-Contained Field
SM Magnetics was engaged to produce a unique toroid magnet with a self-contained and homogenous field. While the design parameters seemed challenging, our engineering teams in the U.S. and China developed a magnet that far exceeded expectations.
The Magnetic Toroid Design Parameters
The customer request was to develop a toroid magnet shaped like a ring — visually similar to a donut. George Mizzell, SM Magnetics’ Engineer and Research Lead, determined how the magnetic field needed to be contained, and equally important, how the part could be manufactured. With the assistance of our manufacturing engineers, the final part was produced as shown above.
The Magnetic Field
Containing the magnetic field presented challenges due to manufacturing techniques and material requirements. The material is a very high-grade NdFeB, so care and consideration had to be given to all aspects of manufacturing and assembly.
To put that field strength into perspective, the assembly was unable to magnetically hold a paperclip on its outer surface. These results were far better than expected.
Application and Research
This magnet is currently being used for R&D by one of our international customers. They will continue to develop tests that provide insight on the uses of contained fields and how these designs might be applied across various applications. Although the external field result was already strong, we believe further development of this design could yield an even weaker external field.
We appreciate the challenge presented to us by our customer for this toroid. We have tackled many unique projects, but this one is another example of pushing the magnetic and manufacturing limits — something we have become familiar with every day.
Engineering Support
For application-specific assembly designs — including contained-field, focused-field, and high-field configurations — our engineering team can support material selection, FEA simulation, and production transition. For evaluation samples and standard parts, see our eCommerce division SuperMagnetMan.