Custom ndfeb magnet

When sourcing NdFeB magnets, you must specify the Grade (e.g., N35 to N52, or high-temp grades like UH, EH), which determines the magnetic energy product (BHmax). Additionally, define the Coating/Plating (such as Ni-Cu-Ni, Zinc, or Epoxy) to prevent oxidation, and ensure Dimensional Tolerances are strictly held to +/- 0.05mm for precision applications. Finally, specify the Magnetization Direction (Axial, Radial, or Multi-pole) to ensure compatibility with your assembly.

Standard NdFeB magnets (N-series) only operate effectively up to 80°C. If your application involves heat, you must select grades with higher coercivity: M (100°C), H (120°C), SH (150°C), UH (180°C), or EH (200°C). Failure to match the grade to the operating temperature will result in irreversible demagnetization, rendering the product useless.

Suppliers must provide RoHS and REACH certifications to ensure the magnets do not contain restricted hazardous substances. For electronics or medical applications, verify ISO 9001 or IATF 16949 (for automotive) quality management systems. If the magnets are used in toys, they must comply with EN71 or ASTM F963 regarding magnetic flux index to prevent safety hazards.

Request a Hysteresis Graph (Demagnetization Curve) from the supplier to verify the actual BHmax and Hcj values. You should also ask for a Salt Spray Test report (typically 24-72 hours) to validate the coating's corrosion resistance. For bulk orders, use a Gauss meter to check surface magnetism consistency across a random sample set.

Magnets are classified as Class 9 Dangerous Goods in air transport if they interfere with aircraft navigation systems. You must ensure the supplier provides Magnetic Shielding Packaging (using iron sheets and foam) and obtains a Non-Dangerous Goods Appraisal Report (DGM report). This is critical to avoid customs seizures or heavy fines from airlines.

The price of Neodymium and Dysprosium fluctuates frequently. It is advisable to link your contract price to a Rare Earth Index or request a quote validity period of no more than 7-14 days. For long-term projects, consider a blanket order to lock in material costs when market prices are low.

The primary risk is Grade Substitution, where a supplier provides N33 instead of N35, or omits heavy rare earth elements required for temperature resistance. Always use Made-in-China.com's Secured Trading services to ensure payment is only released after quality verification, and consider a third-party pre-shipment inspection to test magnetic flux.

Before sending technical drawings for custom shapes, ensure the supplier signs a Non-Disclosure Agreement (NDA). Prioritize Audited Suppliers on Made-in-China.com who have a proven track record of manufacturing for reputable international brands, as they are more likely to respect IP boundaries and technical secrets.