The Five Key Elements of Neodymium Magnet Quotations: Size, Grade, Magnetization Direction, Surface Treatment, and Quantity

1. Size: Dimensional Specifications & Tolerances

The physical dimensions of a neodymium magnet are the most fundamental determinant of cost. Precision in size specifications ensures compatibility with mechanical assemblies, while tolerances affect manufacturing feasibility and waste.

Key Considerations:

• Outer Dimensions (Length × Width × Height):
  • For block/cube magnets, specify exact measurements in millimeters (mm).
  • For ring/disc magnets, provide outer diameter (OD), inner diameter (ID), and thickness.
  • For arc/segment magnets, define radius, chord length, and angle.
• Tolerances:
  • Standard tolerances for neodymium magnets are typically ±0.05 mm to ±0.1 mm, depending on size.
  • Tighter tolerances (e.g., ±0.02 mm) require additional grinding or machining, increasing cost.
• Impact on Pricing:
  • Larger magnets consume more raw material (neodymium, iron, boron), raising costs.
  • Complex shapes (e.g., arcs, trapezoids) require custom tooling, increasing production time and expense.

Example:

A buyer requesting a 10 mm × 5 mm × 2 mm block magnet with ±0.05 mm tolerances will receive a different quote than one requiring ±0.02 mm tolerances due to additional machining steps.

2. Grade: Magnetic Performance & Temperature Stability

Neodymium magnets are graded by their maximum energy product (BHmax), measured in MegaGauss-Oersteds (MGOe). Higher grades offer stronger magnetic fields but are more expensive and temperature-sensitive.

Common Grades & Applications:

Impact on Pricing:

• Higher-grade magnets (e.g., N52, 35SH) cost more due to increased neodymium content and specialized manufacturing.
• Temperature-stable grades (e.g., UH, EH) require dysprosium (Dy) or terbium (Tb) additions, further raising costs.

Example:

An N42 magnet costs less than an N52 magnet of the same size but delivers weaker magnetic output. For high-temperature applications, an N35SH magnet may be preferred despite its lower BHmax due to superior thermal stability.

3. Magnetization Direction: Pole Orientation & Field Strength

The magnetization direction determines how the magnetic field is aligned within the magnet, affecting its performance in specific applications.

Common Magnetization Directions:

• Axial (Through Thickness):
  • Poles are on the top and bottom faces (e.g., a disc magnet with N on one flat face and S on the other).
  • Used in motors, generators, and holding applications.
• Diametrical (Across Diameter):
  • Poles are on opposite curved sides (e.g., a ring magnet with N on one side and S on the other).
  • Used in rotary sensors, flow meters, and magnetic couplings.
• Radial (Multipole):
  • Multiple N-S poles are arranged around the circumference (e.g., a ring magnet with alternating poles).
  • Used in high-precision motors, spindles, and actuators.
• Custom Multipole:
  • Complex patterns (e.g., Halbach arrays) maximize field strength on one side.
  • Requires specialized magnetizing fixtures, increasing cost.

Impact on Pricing:

• Standard axial/diametrical magnetization is less expensive.
• Radial or custom multipole magnetization requires custom tooling, raising production costs by 20–50%.

Example:

A 10 mm × 5 mm block magnet with axial magnetization is cheaper than one with radial magnetization due to simpler manufacturing.

4. Surface Treatment: Corrosion Resistance & Durability

Neodymium magnets are prone to corrosion due to their iron content. Surface treatments protect against rust, wear, and chemical damage, extending lifespan in harsh environments.

Common Surface Treatments:

Impact on Pricing:

• Basic nickel plating is the most cost-effective.
• Epoxy or gold coatings increase costs by 10–30% due to material and process complexity.
• Parylene is the most expensive but offers superior protection in critical applications.

Example:

A N42 magnet with nickel plating costs less than one with epoxy coating but may corrode faster in humid conditions.

5. Quantity: Economies of Scale & MOQ Requirements

The order quantity significantly impacts unit pricing due to setup costs, material waste, and supplier discounts.

Key Considerations:

• Minimum Order Quantity (MOQ):
  • Most suppliers require 1,000–10,000 pieces for standard grades/sizes.
  • Custom magnets may have higher MOQs (e.g., 50,000+ pieces).
• Economies of Scale:
  • Larger orders reduce per-unit cost due to amortized tooling and setup expenses.
  • A 10,000-piece order may cost 30–50% less per magnet than a 1,000-piece order.
• Impact on Lead Time:
  • Small batches (e.g., 100 pieces) may be fulfilled from stock, offering 1–2 week delivery.
  • Large orders require 4–8 weeks for production and quality control.

Example:

A buyer ordering 5,000 N42 magnets will receive a lower per-unit price than one ordering 500 magnets, even if specifications are identical.

Conclusion

When requesting a quotation for neodymium magnets, providing precise details on size, grade, magnetization direction, surface treatment, and quantity ensures accurate pricing and timely delivery. Higher grades, custom magnetization, and advanced coatings increase costs, while larger quantities reduce per-unit expenses through economies of scale. By optimizing these five elements, buyers can balance performance, durability, and budget constraints effectively.

For best results, consult with a magnet supplier early in the design phase to identify the most cost-efficient specifications without compromising application requirements.