Bonded neodymium iron boron (NdFeB) magnets are produced by mixing NdFeB magnetic powder with a polymer binder (typically 2-8% by weight) and forming the mixture into shape using injection molding or compression molding. The polymer binder provides corrosion resistance and allows for complex geometries while retaining magnetic properties.
Key Advantages Over Sintered NdFeB:
NdFeB powder is mixed with polymer binder
Compound is formed into final shape
Optional heat treatment to optimize properties
Parts are magnetized to specification
Quality verification and packaging
| Property | Bonded NdFeB (Injection) | Bonded NdFeB (Compression) | Sintered NdFeB |
|---|---|---|---|
| (BH)max (MGOe) | 5-10 | 8-12 | 35-52 |
| Density (% of full) | 60-75% | 75-90% | 99%+ |
| Shape Complexity | Very High | Medium | Low |
| Tolerance | ±0.02mm | ±0.05mm | ±0.1mm |
| Corrosion Resistance | Excellent | Excellent | Requires coating |
| Max Working Temp | 120-150°C (PPS) | 100-150°C | Up to 230°C |
| Production Volume | Very High | Medium | Low-Medium |
| Typical Cost | Low-Medium | Medium | Medium-High |
| BND-5 | 5 MGOe, general purpose |
| BND-6 | 6 MGOe, good balance |
| BND-8 | 8 MGOe, high performance |
| BND-10H | 10 MGOe, high temp |
| Density | 5.2-5.8 g/cm³ |
| Remanence (Br) | 5.5-7.2 kGs |
| Coercivity (Hcb) | 4.5-6.0 kOe |
| Working Temp | ≤120-150°C |
| BNR-6 | 6 MGOe, entry level |
| BNR-8 | 8 MGOe, standard |
| BNR-10 | 10 MGOe, high performance |
| BNR-12 | 12 MGOe, maximum |
| Density | 6.0-7.0 g/cm³ |
| Remanence (Br) | 6.5-8.0 kGs |
| Coercivity (Hcb) | 5.5-7.5 kOe |
| Working Temp | ≤100-150°C |
| Max Temp | 200°C continuous |
| Chemical Resistance | Excellent |
| Mechanical Strength | High |
| Applications | Automotive, industrial |
| Max Temp | 120-150°C |
| Chemical Resistance | Good |
| Mechanical Strength | Very High |
| Applications | Consumer electronics |
Bonded NdFeB magnets are manufactured using injection molding or compression molding processes. The polymer binder enables design capabilities that are not possible with traditional sintered magnet manufacturing.
| Design Feature | Bonded NdFeB | Sintered NdFeB | Notes |
|---|---|---|---|
| Min Wall Thickness | 0.5mm ✔ | 1-2mm | Injection molding advantage |
| Min Hole Diameter | Ø0.3mm ✔ | Ø1.5mm+ | Micro holes possible |
| Undercuts | ✔ Yes | No | Movable cores available |
| Internal Cavities | ✔ Yes | No | Complex shapes |
| Threads | ⚠ Post-machining | Limited | Usually machined after |
| Draft Angle | 0.5-1° ✔ | 3-5° | Better than powder pressing |
| Tolerance | ±0.02-0.05mm ✔ | ±0.1mm | Precision molding |
| Surface Roughness | Ra 0.8-1.6μm ✔ | Ra 3.2μm+ | Smooth surface finish |
| Gear Profiles | ✔ Yes | No | Molded-in gear teeth |
| Metal Inserts | ⚠ Insert molding | No | Overmolding available |
| Overmolding | ✔ Yes | No | Bonded magnet advantage |
One of the key advantages of bonded NdFeB magnets is their excellent inherent corrosion resistance due to the polymer binder. However, additional surface treatments can further enhance durability in harsh environments.
| Treatment | Compatibility | Applications | Notes |
|---|---|---|---|
| Epoxy Coating | ✔ Recommended | Automotive, outdoor, marine | Most common, provides extra protection |
| E-coating (Electrophoretic) | ✔ Excellent | Automotive, industrial | Uniform coating even on complex shapes |
| Passivation | ✔ Good | Not applicable for ferrite | Chemical treatment for metal surfaces |
| PVD Coating | ⚠ Case-by-case | High-end applications | Temperature sensitivity of binder |
| No Coating | ✔ Standard | Indoor, controlled environment | Polymer binder provides protection |
Bonded NdFeB magnets contain polymer binders that can be affected by extreme temperatures. Please consider:
Consumer electronics, home appliances, office equipment operating in controlled environments typically do not require additional coating.
When the magnet is enclosed in a motor housing or sealed assembly, the inherent corrosion resistance is usually sufficient.
Bonded NdFeB magnets offer excellent cost-effectiveness for high-volume production. Our pricing structure is designed to be transparent and competitive for projects of various scales.
| Factor | Bonded NdFeB | Sintered NdFeB |
|---|---|---|
| Tooling Cost | ¥80K-200K | ¥50K-100K (pressing die) |
| Unit Price (high volume) | Lower | Higher (requires machining) |
| Secondary Operations | Usually none | Grinding, coating often needed |
| Material Utilization | ~99% | 60-70% (machining scrap) |
| Production Speed | Fast (no sintering) | Slow (high-temp sintering) |
| Best for Volume | 10K+ pieces | 1K-10K pieces |
Bonded magnets are formed at relatively low temperatures compared to sintered magnets, significantly reducing production cycle time.
Volume Pricing Trend: As order quantity increases, unit price decreases significantly. Contact us for a detailed quote based on your specific requirements.
Request Custom QuoteBoth injection molding and compression molding capabilities. We recommend the optimal process based on your volume, complexity, and property requirements.
PPS, Nylon, and custom binder systems. We help select the right binder for your temperature, chemical, and mechanical requirements.
Free DFM analysis. We optimize your part design for molding, magnetization, and assembly integration.
ISO 9001, IATF 16949 certified. Full magnetic testing, dimensional inspection, and salt spray testing capabilities.
Automated production lines for millions of parts per year. Consistent quality from first part to millionth.
Standard parts ship in 7-15 days. Tooling lead time 4-6 weeks. Express service available.
Choose bonded NdFeB when you need: complex shapes that cannot be machined, integrated features (shafts, housings), high-volume production, excellent corrosion resistance without coating, or tight tolerances without post-machining.
PPS-bonded magnets can operate up to 150°C continuously. Nylon-bonded magnets typically up to 120-130°C. For higher temperatures, sintered NdFeB with appropriate grades (SH, UH) may be required.
Yes, bonded magnets have good mechanical strength, especially compression-molded types. However, they are not suitable for high mechanical stress applications where the magnet is a load-bearing component.
Bonded magnets can be multipole magnetized (axial, radial), with pole counts from 2 to 48 or more. Complex magnetization patterns are possible due to the isotropic nature of the material.
Tooling: 4-6 weeks. Samples: 1-2 weeks after tooling approval. Production: 2-4 weeks after approval. Standard catalog parts can ship within 7-15 days.
Yes, we offer integrated assembly services including overmolding, insert molding, and complete motor sub-assembly manufacturing.
Contact our bonded magnet specialists for custom quotes, samples, or technical consultation. We help you select the optimal process and material for your application.
Contact: Cindy | Phone: +86 021 5512 8901 | Email: sales1@brm-metal.com
