The number in a sintered NdFeB grade relates to an energy-product class, not a direct ranking of finished pull force or surface field. Geometry, temperature, magnetic circuit and assembly also matter. Start with the function, then compare material data within the project conditions.
Separate the material, the finished magnet and the product
A grade describes magnetic material properties. Finished performance also depends on size, shape and magnetization; product function depends on mating parts and spacing. A higher grade number, a higher center reading and a more suitable product are different conclusions.
If the material is already specified, review it against the required data. If the goal is a more reliable closure or easier removal, share the geometry and validation conditions. An unconfirmed grade should not become a substitute for the actual design objective.
Read the suffix and the type of value
Common suffixes identify coercivity families relevant to temperature selection. Distinguish remanence, normal coercivity, intrinsic coercivity and maximum energy product. Also distinguish typical values from minima; comparisons need the same definition.
The grade example explains notation. Parameters and limits must refer to the actual material data, rather than an assumption that every identically named grade has identical values.
Review temperature in the operating magnetic circuit
Temperature selection requires more than a reference number. Shape, circuit conditions, opposing fields and thermal history influence demagnetization risk. Match the source conditions to the application; Curie temperature is not the permitted operating temperature.
Describe normal operation, possible short exposures and any heating or adhesive curing during assembly. The finish, adhesive and injection binder have their own conditions. One compliant component does not by itself establish a compliant assembly.
| Project factor | Information to review |
|---|---|
| Space and geometry | Available volume, thickness, pole faces and machined features |
| Magnetic requirement | Field or function, with its measurement conditions |
| Temperature and circuit | Working/transient temperatures, mating parts and opposing fields |
| Assembly and protection | Gaps, bonding, coatings and media |
| Cost and delivery | Samples, pilots, batch volumes and adjustable design features |
Identify the variables before fixing the grade
In some projects, geometry or gap changes deserve review alongside grade changes. In a fixed envelope, material and structural trade-offs may dominate. There is no universal ranking across products; compare options against the same functional boundary.
List what is fixed, what may change and how success will be checked. For example, retain the housing and gap while comparing feasible options, or explore available thickness before selecting a material. These are evaluation approaches, not unverified performance promises.
Turn reference data into a project specification
The website table helps explain published material data and value definitions. It is not the agreed supply specification. Confirm the source, values and inspection requirements for the actual material. Injection-bonded NdFeB should not be specified using the sintered table.
If the grade is undecided, start with space, environment, mating parts and function. These inputs support a practical material, sample and validation discussion more effectively than requesting the highest available number.