Multipole rotor in a segmented magnetizing fixture — assembled first, magnetized in-fixture at the end of the line.
What we build
Six assembly families, one quality system
Every assembly is built to your dimensional drawing, with the magnet grade, coating, adhesive system, and magnetization method documented in the control plan.
Rotor assemblies
Arc segments or ring magnets bonded to your hub or shaft, dynamically balanced to your G-grade spec. SPM and surface-bonded rotor builds for BLDC and servo programs.
Radial multipole rings
Multipole-magnetized radial rings pressed or bonded onto hubs — the compact joint-motor format humanoid robotics and precision servo designs run on.
Encoder & sensor targets
Diametric discs and multipole target wheels mounted to carriers, with pole-position accuracy specified and verified for magnetic encoder feedback.
Halbach arrays
Linear and ring Halbach arrangements assembled in-fixture, where segment orientation and bonding sequence decide whether the array meets its flux map.
Over-molded carriers
Magnets insert-molded or potted into plastic carriers and housings — sealed against the environment and ready for your line, no magnet handling required.
Bonded holding assemblies
Pot magnets, fixture plates, and custom holding assemblies built around sintered NdFeB where the bracket, thread, and coating are part of the spec.
Why buy the assembly, not the magnet
A cheaper magnet is not a cheaper rotor
Per-kilo magnet pricing hides the engineering cost that lands on your line: incoming inspection of magnetized parts, adhesive qualification, balancing rework, and tolerance disputes between three suppliers. Buying the qualified sub-assembly moves that work — and the accountability for it — to us.
The tolerance stack-up is engineered once
When the magnet supplier also builds the assembly, magnet tolerance, adhesive gap, and carrier machining are designed together — not discovered at your incoming inspection.
One incoming part number
You inspect one assembly to one drawing, instead of receiving magnets, adhesive, and hardware separately and owning the integration risk yourself.
Adhesive qualified by the people who chose the magnet
Bond strength is coating-dependent. We qualify the epoxy system against the actual magnet coating and your operating temperature, and document it in the PPAP.
Magnetize after assembly
Where the design allows, assemblies are built unmagnetized and magnetized in-fixture at the end — no magnetized-part handling on your line, cleaner assembly, accurate pole placement.
Export paperwork on the assembly
MOFCOM classification, licensing where required, and documentation are handled on the finished sub-assembly — one customs line, managed by a team that does this weekly.
How a program runs
From assembly drawing to PPAP in five steps
01
DFM review
Send the assembly drawing. We review magnet geometry, bond gaps, carrier material, and magnetization method, and flag anything that will cost money before tooling does.
02
Magnet + bonding plan
Grade selection, coating matched to the adhesive system, and a bonding and curing plan rated to your operating temperature.
03
Fixtures and pilot build
Assembly and magnetization fixtures built, pilot lot produced, dimensional and flux results documented against the drawing.
04
Balance, magnetize, verify
Dynamic balancing to spec, in-fixture magnetization where the design allows, flux mapping and pull-test verification per the control plan.
05
PPAP and production
PPAP Level 3 documentation on the assembly, batch records per lot, and production at your call-off rate.
What to send for a quote
The more of this you include, the faster the quote. Pricing follows within 2 business days; a human replies within 1.
- —Assembly drawing (STEP or PDF) — or the magnet drawing plus the mating parts
- —Magnet spec if you have one, or the flux / torque target if you don't
- —Operating temperature and environment
- —Annual volume and target price, if you can share them
- —Required documentation level (PPAP, IMDS, material certs)
Questions buyers ask
Assembly programs, answered straight
Do you manufacture the assemblies yourselves?
Mainrich engineers the assembly and owns the specification, quality system, and export licensing. Production runs across the four-site manufacturing network we have built and hold stakes in over 30 years — magnet production, machining, bonding, and balancing under one IATF 16949 quality system, with our engineers accountable for every lot.
Can you work from just a torque or flux target?
Yes. If you have the envelope, the operating temperature, and the performance target, we propose the magnet grade, geometry, and assembly method. A feasibility review and grade recommendation costs nothing and typically takes 2 business days.
Are assemblies affected by Chinese export licensing?
It depends on the magnet inside. Assemblies built on our F-Series (HREE-free) magnets need no MOFCOM license and ship in normal lead times. Assemblies using Dy/Tb-bearing grades can require licensing — we classify, file, and manage that on the finished assembly, and tell you the realistic timeline before you place the PO.
What volumes do you support?
Prototype and qualification lots are normal — single-piece samples are fine. Production programs run from hundreds to hundreds of thousands of assemblies per year.