Magnet Overmolding on Steel Shafts

Direct injection molding of bonded NdFeB or ferrite magnet material onto steel shafts to eliminate gluing and secondary assembly steps.

Best Fit For:Best for motor and pump assembly teams seeking to reduce BOM count, eliminate curing times, and improve mechanical reliability.

Capability Highlights

Eliminates the risk of adhesive failure between magnet and shaft
Guarantees perfect concentricity by using the shaft as the mold datum
Supports knurled, splined, or slotted steel inserts for maximum torque retention

Typical Engagement Scope

Automotive pump impellers
BLDC motor shafts
Throttle valve shafts
EPS worm gear shafts

Execution Focus

Insert surface knurling design for torque and pull-out resistance
Overmolding pressure and thermal stress on thin shafts
Mold design to prevent magnetic powder flash on bearing surfaces

Program Evaluation Matrix

Program Metric	Typical Range	Procurement Value
Concentricity (TIR)	Achieves higher precision than glued assemblies since the shaft is fixtured in the mold	In high-speed pump or motor applications, runout causes vibration, noise, and accelerated bearing wear.

RFQ Preparation Checklist

2D/3D drawing, material target, magnetic pattern, and sensing datum
Operating temperature, vibration, media exposure, and lifetime requirement
Sample quantity, tooling target, annual forecast, destination, and PPAP needs
Shaft material, surface finish, knurling drawing, and retention torque target

Risk and Mitigation

Brittle sintered magnet carried into a vibration-critical assembly: Review bonded magnet material and molded geometry when chipping, cracking, or adhesive failure can affect functional safety.
Magnetic pattern accepted without measurable criteria: Define flux density, pole count, angle error, sensing radius, concentricity, and inspection method before sample tooling.

Related Products

Buyer FAQ

Does the steel shaft affect the magnetization pattern?

Yes, magnetic inserts (like steel) alter the flux path. We review the insert material and dimensions during DFM to ensure the magnetization fixture compensates for it.

Related Resources

Insert Molding and Magnet Overmolding

Inquiry Email

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Include drawing, material, pole pattern, quantity, and destination.

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+8618857971991

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Program Metric

Typical Range

Procurement Value

Concentricity (TIR)

Achieves higher precision than glued assemblies since the shaft is fixtured in the mold

In high-speed pump or motor applications, runout causes vibration, noise, and accelerated bearing wear.

Risk and Mitigation

Brittle sintered magnet carried into a vibration-critical assembly: Review bonded magnet material and molded geometry when chipping, cracking, or adhesive failure can affect functional safety.

Magnetic pattern accepted without measurable criteria: Define flux density, pole count, angle error, sensing radius, concentricity, and inspection method before sample tooling.