Identifying Magnet Grade for FEMM Simulation: Neodymium Cylinder Magnets

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Discussion Overview

The discussion revolves around identifying the grade of neodymium cylinder magnets based on provided magnetic properties and dimensions for use in a FEMM simulation. Participants explore the implications of magnet grade on magnetic strength and the challenges of deriving it from available data.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant seeks to identify the magnet grade from a paper that does not specify it, providing dimensions and magnetic measurements.
  • Another participant suggests that the dimensions and magnetic properties listed might allow for a straightforward lookup of the grade.
  • A different participant requests more information about the equation used, indicating that the setup of the coordinates is crucial for understanding the results.
  • The original poster clarifies that "grade" refers to classifications like N52 or N40, emphasizing the importance of knowing the grade for determining magnet strength.
  • One participant proposes that the saturation magnetization could help identify a suitable magnet grade, suggesting N30 as a potential match based on the saturation magnetization value provided.

Areas of Agreement / Disagreement

Participants express varying levels of understanding regarding the term "grade" and its significance, with some agreeing on its importance while others remain uncertain about how to derive it from the given data. The discussion does not reach a consensus on the correct magnet grade.

Contextual Notes

Participants note limitations in the information provided, such as the lack of clarity on the equation's derivation and the specific setup used in the referenced paper. There is also uncertainty regarding the relationship between the measured magnetic field and the residual magnetism.

Who May Find This Useful

Individuals interested in magnet properties, FEMM simulations, or those working with neodymium magnets in experimental or applied contexts may find this discussion relevant.

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TL;DR
I need indetify a magnet grade from an academic paper but I only have the surface fields and the saturation magnetization.
Hello. I need to indetify a magnet grade from an academic paper, they dont mention what grade is . I am trying to simulate de contact force bewten two magnets on FEMM and to validate the results I am using one ecuation of that paper, but they dont specify what grade the Neodymium magnet is, only give the data that they got of a gaussmeter and the saturation magnetization the magnets are cylinders with D=3mm and H=1.5mm. The data of the gaussmeter is B= 1.07 T and the saturation magnetization M = (0.859) MA/m.

I tried to solve an equation that I found
1699480620658.png
and with Br I can search to what grade is, but when a solve the Br is higher even for N52 magnets.

Please Help me, I attach a part of the paper perhaps there is something that I can see.

Thank you

1699480455969.png
 
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I don’t know what “grade” is, but they list the dimensions, magnetic properties and the name of the manufacturer! Just look it up.
 
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marcusl said:
I don’t know what “grade” is, but they list the dimensions, magnetic properties and the name of the manufacturer! Just look it up.
Yeah, I hadn't heard that term either, but from a web search it does seem to be something that the manufacturer would specify:

1699488199729.png

https://www.kjmagnetics.com/blog.asp?p=magnet-grade
 
Need more information. The formula you gave doesn't help if we don't know how the coordinates used to derive it were setup. Could you identify the paper and where you got the equation?
 
Thank you for your answers. Like berkeman wrote, the grade is the classification of neodymium magnets for example N52 or N40. The paper is :
"Magnetostatic interactions and forces between cylindrical permanent magnets" by
David Vokoun, Marco Beleggia.

This paper used a permanent magnet, but they don’t explain what grade is, I need to know because depend on the grade are the properties for example the magnet strength. The paper only mention that they measured with a gaussmeter and got B= 1.07 T that I supposed is the magnetic field in the surface, so there is one equation in (https://www.supermagnete.de/eng/faq/How-do-you-calculate-the-magnetic-flux-density) to calculate the magnetic field on the surface I tried to use that equation to get the Br (residual magnetism) and with that I could found to what grade is. But it does not work. Because it gave me Br=2.41 T con z=0mm, and there aren´t materials with that Br.
 
Hi guys, finally I guess that I found the answer. The saturation magnetization is the higher part of the curve in a demagnetization curve :

1699984867912.png

image took from:
(https://mriquestions.com/magnetizing-metal.html)

So, with the saturation magnetization M = (0.859) MA/m I just search a magnet with the nearest value perhaps the NdFeB N30, it depends on the supplier.

For example, I found this supplier.
https://www.arnoldmagnetics.com/wp-content/uploads/2017/11/N30-151021.pdf
and the magnetic saturation is 11 kGauss comparing between M = (0.859) MA/m=10.7 KGauss I think its ok.

I hope this could help to someone.
 

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