What is the pull force of a Φ20×5 mm N42 disc magnet?

A Φ20×5 mm N42 disc magnet has a typical pull force of approximately 32–38 N against a 10 mm mild steel plate at zero air gap. Our N48 version of the same size achieves approximately 52 N.

Disc & Cylinder · Factory Direct

Neodymium Disc Magnets — N35 to N52, Custom Diameters & Coatings

Q: What grades are available for neodymium disc magnets?

We produce disc magnets from N35 through N52 for standard operating temperatures (up to 80°C), plus H (120°C), SH (150°C), UH (180°C), and EH (200°C) suffix grades for high-temperature environments. For most industrial and sensor applications, N42 or N48 provides the best balance of strength, stability, and cost.

Q: What is the difference between axial and diametral magnetization?

Axial magnetization means the north and south poles are on the flat faces (top and bottom) — standard for most disc magnet applications. Diametral magnetization means poles are on the curved edge, used in encoder wheels and rotating sensor systems. Both options are available.

Q: Can you customize disc magnet size, coating, and tolerance?

Yes. We accept any diameter from Φ3 mm to Φ100 mm and thickness from 1 mm upward. Standard tolerance is ±0.05 mm; ±0.02 mm precision available for encoder and sensor applications. Coatings include Ni-Cu-Ni, Zn, Epoxy, Gold, Silver, PTFE, and Parylene.

Q: How do I choose between N42 and N52 for my disc magnet design?

N42 has higher intrinsic coercivity (Hcj ≥955 kA/m), making it more resistant to demagnetization — ideal for motors, sensors, and most industrial assemblies. N52 delivers the highest energy product (up to 422 kJ/m³) for space-constrained holding applications. N52 has lower coercivity and is more sensitive to heat and opposing fields.

Q: Are your neodymium disc magnets RoHS and REACH compliant?

Yes. All disc magnets comply with RoHS 3 (EU Directive 2015/863) and REACH SVHC regulations. Material declaration, MSDS, and RoHS certificates are included with every order.

Q: What is the MOQ and lead time for disc magnets?

Standard stock sizes: MOQ 100 pcs, available within 3–5 business days. Custom sizes: MOQ 100 pcs, lead time 15–20 business days after prototype approval. Fast-track sample service in 5–7 business days available on request.

Sintered NdFeB disc magnets in any diameter (Φ3–Φ100 mm), any grade, any coating. Axial or diametral magnetization. ±0.05 mm tolerance. ISO 9001 & IATF 16949 certified. MOQ 100 pcs. Quote in 24 hours.

ISO 9001:2015 IATF 16949 ISO 14001 RoHS / REACH

Request a Free Quote → Talk to an Engineer

30+

Years mfg.

40+

Countries served

±0.05mm

Tolerance

24h

Quote response

Zinc-plated neodymium disc magnets for industrial applications | Mainrich Magnets

Capabilities

What We Manufacture for Disc Magnet Orders

From standard stock sizes to fully engineered custom disc magnets — any dimension, any grade, any coating.

◉

Disc & Cylinder Sizes

Diameter: Φ3 mm → Φ100 mm
Thickness: 1 mm → 50 mm
Standard stock: Φ10–Φ30 mm (in-stock)
Tolerance: ±0.05 mm (Φ ≤ 20 mm)
Tolerance: ±0.10 mm (Φ 20–60 mm)
Tolerance: ±0.15 mm (Φ > 60 mm)
Precision: ±0.02 mm on request
Countersunk hole available

⚡

Grade Range

N35 → N52 (standard, up to 80°C)
N__M — up to 100°C
N__H — up to 120°C
N__SH — up to 150°C
N__UH — up to 180°C
N__EH / AH — up to 230°C

◎

Coating Options

Nickel (Ni-Cu-Ni) — standard
Zinc — industrial / outdoor
Epoxy — chemical resistance
Gold / Silver — conductive apps
Parylene C/D — medical devices
Uncoated / Phosphated

Technical Specifications

Common Disc Magnet Sizes & Grades

Standard stock dimensions across common grades and coatings. Custom sizes quoted within 24 hours.

Dimensional tolerance varies by size: ±0.05–±0.15 mm standard (larger parts carry wider tolerance). Precision ±0.02 mm available on request. Dimensional reports and magnetic certificates included with every shipment.

Size (D × H)	Grade	Coating	Stock
Φ10 × 2 mm	N35	Ni-Cu-Ni	In Stock
Φ15 × 3 mm	N42	Ni-Cu-Ni	In Stock
Φ20 × 3 mm	N42	Ni-Cu-Ni	In Stock
Φ20 × 5 mm	N48	Ni-Cu-Ni	In Stock
Φ25 × 5 mm	N42	Ni-Cu-Ni	In Stock
Φ30 × 5 mm	N50	Ni-Cu-Ni	In Stock
Φ40 × 8 mm	N52	Epoxy	Custom
Φ50 × 10 mm	N52	Ni-Cu-Ni	Custom
Φ60 × 10 mm	N52	Epoxy	Custom
Φ80 × 15 mm	N42	Zinc	Custom

* Custom sizes available in any diameter Φ3–Φ100 mm. MOQ 100 pcs. Lead time 15–20 business days.

NdFeB N52 demagnetization curve for neodymium disc magnet performance verification | Mainrich Magnets

Magnetic Properties by Grade

Grade	Br (T)	Hcb (kA/m)	Hcj (kA/m)	(BH)max (kJ/m³)	Max Temp (°C)
N35	1.17–1.22	≥868	≥955	263–287	80
N38	1.22–1.25	≥899	≥955	287–310	80
N42	1.28–1.32	≥915	≥955	318–342	80
N45	1.32–1.38	≥923	≥955	342–366	80
N48	1.37–1.43	≥923	≥955	366–390	80
N50	1.40–1.45	≥796	≥876	382–406	80
N52	1.43–1.48	≥796	≥876	398–422	80
N42H	1.28–1.32	≥915	≥1353	318–342	120
N42SH	1.28–1.32	≥915	≥1592	318–342	150
N38UH	1.22–1.25	≥899	≥1990	287–310	180
N35EH	1.17–1.22	≥868	≥2388	263–287	200

* Values per IEC 60404-8-1 at 20°C. CoA and B-H curves included with every order.

Our Process

From Your Drawing to Your Door in 4 Steps

Engineering support and full documentation at every stage. No delays, no surprises.

Submit Requirements

Share diameter, thickness, grade, coating, magnetization direction, and quantity. Unsure on grade? Our engineers recommend the right spec within 24 hours — free of charge.

Engineering Review

DFM analysis and pull force simulation before cutting. We flag manufacturability issues before production begins — saving you time and tooling cost.

Prototype & Approval

50-pc prototype batch with dimensional inspection report and pull force test data. Approval typically takes 3–5 business days.

Mass Production

100% dimensional inspection and sampled magnetic performance testing. Shipment includes CoC, test reports, and RoHS / REACH declaration.

Have a drawing? Upload for a free DFM review → | Need a sample first? Contact our team →

Custom Solutions

Customized Disc Magnet Solutions

Get precise, reliable performance with disc magnets tailored to your exact specifications. Mainrich adjusts size, grade, coating, magnetization direction, and tolerance to match your assembly requirements.

Custom neodymium disc magnets — tailored sizes, grades and coatings, factory direct from Mainrich | Mainrich Magnets

Our Tailored Service List

Custom Sizes Diameter Φ3–Φ100 mm, thickness 1 mm+. Standard tolerance ±0.05 mm, precision ±0.02 mm available.

Custom Grades N35 to N52AH — select the grade that suits your operating temperature and demagnetization resistance requirements.

Coating Options Ni-Cu-Ni (standard), Zinc, Epoxy, Gold, Silver, or Parylene — chosen for your environment and compliance needs.

Magnetization Direction Axial (poles on flat faces) or diametral (poles on curved edge) — or multi-pole for encoder ring applications.

Tight Tolerances Standard tolerance: ±0.05–±0.15 mm (size-dependent — Φ ≤ 20 mm: ±0.05 mm; Φ 20–60 mm: ±0.10 mm; Φ > 60 mm: ±0.15 mm). Precision ±0.02 mm available via CNC grinding and wire EDM.

Get a Fast Quote Today →

Applications

Industries We Manufacture Disc Magnets For

Neodymium disc magnets are the most versatile NdFeB shape — used across high-tech industries worldwide.

Electric Vehicle

EV & Motor Systems

Axially magnetized N42SH disc magnets for voice coil actuators and rotor position sensing in PMSM drive systems.

DC motor magnet guide →

Robotics & Automation

Industrial Robotics

High-precision disc magnets for servo encoder rings, end-effector grippers, and magnetic couplings. ±0.02 mm tolerance for tight air-gap control.

Magnets in robotics →

Medical Devices

Medical-Grade Magnets

Parylene C/D coated disc magnets for implantable and surgical tools. Full lot traceability and MSDS documentation.

Medical magnets

Sensors & Electronics

Sensors & Reed Switches

Miniature disc and cylinder magnets for Hall-effect sensors, proximity switches, and haptic feedback. Br tolerance ±0.02 T for production-line calibration.

Sensor magnets

Renewable Energy

Wind Turbine Generators

Large-format N50 and N52 disc magnets for direct-drive PMGs and pitch control sensors.

Wind energy magnets

Industrial

Holding & Clamping

High pull-force N52 disc magnets for magnetic chucks, workholding fixtures, and magnetic separators. Custom diameters up to Φ100 mm.

Custom magnet options →

Why Mainrich

What Sets Our Disc Magnet Manufacturing Apart

Four reasons engineers and procurement managers choose Mainrich for long-term supply.

30+ yrs

Proven Manufacturing History

Founded in 1992, Mainrich has shipped to customers in 40+ countries and serves as a certified supplier to Tier-1 automotive manufacturers. Our experience means fewer surprises, faster problem resolution, and a supply chain you can rely on long-term.

100%

Vertically Integrated Production

We control every step from sintering to final magnetization — no subcontracting. In-house CNC grinding achieves ±0.05 mm tolerances other suppliers send out for. Result: faster lead times, tighter quality control, and cost savings passed to you.

3× Cert.

IATF 16949 + ISO 9001 + ISO 14001

Triple certification means your procurement team won't need a new supplier audit. We provide all automotive quality documentation — PPAP, FMEA, Control Plans — on request. Automotive-grade supply chain compliance is already built in.

±0.02T

Tight Br Tolerance for Sensor Lines

Standard production Br variation is ±0.04 T. For sensor and encoder applications, we offer tight-Br batches at ±0.02 T — ensuring Hall-effect sensor calibration holds across production runs without re-calibration.

Factory Showcase

From raw rare-earth materials to finished disc magnets — every step is controlled in-house across our dedicated production facility.

Raw Material Warehouse

Melting Workshop

Powder Making

Molding Workshop

Sintering Workshop

Testing Laboratory

CNC Machining

Electroplating

Inspection and Packaging Workshop at Mainrich Magnets factory | Mainrich Magnets

Inspection & Packaging

Shipping Warehouse

Full in-house: Raw Material → Melting → Powder → Sintering → Machining → Plating → QC & Ship

Get Free Quote

FAQ

Frequently Asked Questions — Neodymium Disc Magnets

Common questions from engineers and procurement managers. Can't find your answer? Contact our team →

What grades are available for neodymium disc magnets? −

We produce disc magnets from N35 through N52 for standard operating temperatures (up to 80 °C), plus H (120 °C), SH (150 °C), UH (180 °C), and EH (200 °C) suffix grades for high-temperature environments. For most industrial and sensor applications, N42 or N48 provides the best balance of strength, stability, and cost.

What is the difference between axial and diametral magnetization? +

Axial magnetization: North and south poles are on the flat faces (top and bottom) — standard for most disc magnet applications, including holding, sensing, and motor positions.

Diametral magnetization: Poles are on the curved edge — used in encoder wheels, rotary sensors, and applications where the magnet spins. Both are available; please specify when requesting a quote.

Can you customize disc magnet size, coating, and tolerance? +

Yes. We accept any diameter from Φ3 mm to Φ100 mm and thickness from 1 mm upward. Standard tolerance is size-dependent: ±0.05 mm for Φ ≤ 20 mm, ±0.10 mm for Φ 20–60 mm, and ±0.15 mm for Φ > 60 mm. Precision ±0.02 mm available on request for encoder and sensor applications. Coatings include Ni-Cu-Ni, Zn, Epoxy, Gold, Silver, PTFE, and Parylene. Please provide a drawing or DXF file for quote accuracy.

How do I choose between N42 and N52 for my disc magnet design? +

N42 has higher intrinsic coercivity (Hcj ≥955 kA/m), making it more resistant to demagnetization from opposing fields or elevated temperature — ideal for motors, sensors, and most industrial assemblies.

N52 delivers the highest energy product (up to 422 kJ/m³), maximizing pull force in the smallest possible volume — best for space-constrained holding and clamping applications. However, N52 has lower coercivity and is more sensitive to heat and opposing fields. Engineering review is recommended before specifying N52 in motor assemblies. See our full N42 vs N52 comparison guide →

Are your neodymium disc magnets RoHS and REACH compliant? +

Yes. All disc magnets comply with RoHS 3 (EU Directive 2015/863) and REACH SVHC regulations. Material declaration, MSDS, and RoHS certificates are included with every order. Epoxy, Nickel, and Zinc coatings all meet EU environmental and safety standards. See the official EU RoHS Directive and ECHA SVHC list for compliance references.

What is the MOQ and lead time for disc magnets? +

Standard stock sizes: MOQ 100 pcs, available within 3–5 business days.
Custom sizes: MOQ 100 pcs, lead time 15–20 business days after prototype approval.
Urgent prototype: Fast-track sample service in 5–7 business days available on request. Contact us to discuss your timeline.

Related Resources

Get a Custom Quote for Neodymium Disc Magnets

Tell us your diameter, thickness, grade, coating, and quantity — we respond within 24 hours with pricing and a technical recommendation from our engineering team.

Request a Quote → Contact Us

Factory Direct Pricing ISO 9001 & IATF 16949 Certified RoHS / REACH Compliant 24h Quote Response Free Sample Available