Two materials. Two forming approaches.
Sintered NdFeB
A dense magnetic material produced by powder metallurgy and machined to suit the geometry and magnetic requirements.
Injection-bonded NdFeB
Magnetic powder and a thermoplastic binder are compounded and injection molded. Properties depend on the material system, powder loading and geometry. This page focuses on injection bonding.
Principle only: dense sintered material on the left; magnetic powder dispersed in a polymer matrix on the right. This is not a micrograph or a representation of particle loading or scale.
Injection bonding forms a magnetic composite from powder and binder. Overmolding plastic around a sintered magnet is a different construction. Color alone does not identify the binder or grade.
Select for geometry and operating conditions.
| Factor | Sintered NdFeB | Injection-bonded NdFeB |
|---|---|---|
| Magnetic properties | Typically offers higher energy product; confirm the grade and circuit. | Depends on powder, loading, orientation and binder; do not apply sintered grades. |
| Geometry and assembly | Standard and custom machined profiles; consider brittleness and edges. | Molds can form holes and lugs; review demolding and shrinkage. |
| Dimensions and quantities | Review machining tolerances, finished dimensions and batch requirements. | Review tooling, tolerances, shrinkage and total cost at the required volume. |
| Temperature and environment | Review grade, geometry, circuit and surface protection. | Review both powder properties and binder temperature/moisture behavior. |
Start with the space envelope and drawing, holding or field requirements, temperature/humidity and contact media, and sample/batch quantities.
Understand the forming routes.
Sintered route
Alignment pressing establishes the easy-axis orientation. Sintering and heat treatment form the material, followed by machining. Finishing steps are arranged for the product.
Injection-bonded route
Anisotropic powder systems may need an aligning field during molding. Alignment and final magnetization are different steps. This simplified route varies with the material and geometry requirements.