Customized Laminated Magnets for High-Tech Applications

Custom Laminated Magnets & Stacked Magnetic Steel — Low Eddy Current Loss NdFeB / SmCo Assemblies for High-Speed Motors, Robotics, and Semiconductor Equipment

Custom shapes, custom materials, full Halbach array support — cut eddy current loss 60-90% and unlock motor efficiency

FAIZEAL custom laminated magnets are precision-engineered magnetic assemblies built by stacking ultra-thin, electrically insulated layers of sintered NdFeB or samarium cobalt into a single magnet shape. The lamination process interrupts the eddy-current loop that would otherwise form inside a solid magnet under alternating magnetic fields, cutting eddy current losses by 60-90% and reducing temperature rise by 30-50% in high-frequency operation. The result is a motor-friendly magnet that holds its flux, runs cooler, and lets designers push switching frequency, current density, and continuous power higher without crossing the thermal demagnetization line.

For high-speed servo motors, humanoid robot joint motors, EV traction motors, linear motor tracks, semiconductor lithography stages, aerospace actuators, and high-precision sensor assemblies, laminated magnets are now the default building block. Every FAIZEAL assembly is 100% custom — material grade, lamination thickness, insulation chemistry, geometry, surface treatment, and magnetization pattern are all specified to your design. Send a CAD or STEP file, a target flux and loss budget, or an existing solid-magnet drawing and FAIZEAL returns a manufacturable lamination proposal, an FEA-based loss estimate, and a prototype plan.

Why laminated magnets replace solid magnets in modern high-tech motors

A solid sintered NdFeB or SmCo magnet is electrically conductive. In an alternating magnetic field, time-varying flux drives eddy currents in the magnet body, and those currents dissipate as I-squared-R heat. The loss scales with the square of the magnet thickness, so a 5 mm solid magnet can show 20-50 times the eddy loss of a 0.35 mm laminated stack under the same field. At PWM fundamental frequencies of 5-20 kHz — typical of modern SiC drives — this is the difference between a motor that runs cool and a magnet that creeps past its thermal limit, demagnetizes, and fails the warranty.

Laminated magnets solve this by cutting the magnet into thin slices, separating each slice with a thin dielectric insulation layer, and bonding them back into the original geometry. The eddy current loop is broken into many small loops, each dissipating a fraction of the original loss, and total loss falls proportional to the square of the slice thickness. The result is a magnet that performs like a solid magnet mechanically and magnetically, but behaves electrically like a stack of thin, low-loss laminations.

Key benefits for the design engineer

· Low eddy current loss and cooler operation. Custom lamination thickness (0.10-2.00 mm) and insulation chemistry (epoxy, polyimide, parylene-C, ceramic-filled, Al2O3) reduce eddy current loss by 60-90% and lower temperature rise by 30-50% versus a solid magnet of the same shape, in the same drive and cooling conditions.

· Full geometric flexibility. Sector / fan-shape, tile / arc-shape, rectangular block, square, and complex irregular geometries are all in-house. Typical planar dimensions from 10x10 mm up to 200x200 mm and stack heights from 3 mm to 60 mm. Custom sizes outside the standard envelope are evaluated on request.

· Multiple material options. Sintered NdFeB (N35 to N52; H / SH / UH / EH / AH grades for elevated temperature) and SmCo 1:5 or Sm2Co17 for high-temperature and corrosion-edge applications. The material is selected to give sufficient Hcj margin against the worst-case working point at maximum operating temperature and reverse field.

· Halbach array magnetic circuit support. Lamination is the ideal building block for Halbach arrays, where each pole pitch is split into 3-8 segments with rotated magnetization directions. The laminated construction controls eddy loss in every individual segment, preserves Halbach single-face flux concentration (+25-40% versus radial-magnet), and reduces cogging force by 50-80%.

· High motor efficiency. Lower magnet loss means less waste heat, smaller heat sinks, and higher continuous power density. In high-frequency applications, laminated magnets routinely add 1-3 percentage points to overall motor efficiency, enough to be the difference between a design that passes efficiency class and one that does not.

· Tight tolerance, OEM-ready. Lamination layer parallelism ±0.02 mm, stack height tolerance ±0.05 mm (down to ±0.02 mm for precision grade), surface flatness 0.03 mm, surface roughness Ra 0.4-0.8 um. Each assembly ships with dimensional report, material certificate, and FEA-based loss estimate.

· Versatile shape and assembly. The lamination stack is built to your CAD envelope — single-piece, multi-piece, or segmented with bolt-pattern interfaces. Sector modules can be precision-joined into arc, partial ring, or full 360-degree annular tracks. Mounting features (through-holes, threaded inserts, dowel pins) are integrated in the same build.

· Long service life in harsh environments. SmCo versions are rated to +350 deg C continuous; Ni-Cu-Ni plated NdFeB versions pass 1000 h salt spray. Parylene-C and epoxy topcoats are available for medical, marine, and chemical environments. Material grade, insulation, and coating are matched to the operating envelope so the assembly holds its magnetic performance across the full service life.

Material and shape selection reference

The tables below summarize the standard production envelope. Combinations outside these ranges are evaluated on request.

Geometry / shape selection reference

Frequently asked questions (B2B engineer FAQ)

Q1. What lamination thickness should I choose for a 10 kHz drive?

A. For PWM fundamental around 10 kHz with switching harmonics into the 100 kHz range, the skin depth in sintered NdFeB is in the 0.15-0.25 mm range. We recommend a single-layer thickness of 0.20-0.30 mm. Thinner layers cut loss further but raise lamination count and unit cost; thicker layers above 0.50 mm start to show measurable eddy heating. For 1-3 kHz fundamental (typical EV traction) 0.35-0.50 mm is usually the right balance. FAIZEAL engineering will run an FEA loss estimate for your specific drive and pick the right point.

Q2. What is the standard insulation layer and how thin can it go?

A. Standard insulation is an epoxy resin bond-line of 10-25 um between layers, with dielectric strength of 20-40 kV/mm. For higher temperature or higher dielectric demand, we use ceramic-filled epoxy, polyimide film, parylene-C (5-25 um, vacuum deposited, dielectric 200+ kV/mm), or thin-film Al2O3 (1-5 um, dielectric 200+ kV/mm). Insulation thickness is part of the design — thinner is mechanically weaker and harder to control, so we work with you to pick the minimum that meets the dielectric and thermal targets.

Q3. What machining tolerances can FAIZEAL hold on laminated magnets?

A. Standard production holds ±0.05 mm on outer dimensions and ±0.02 mm on lamination layer parallelism. Precision grade goes to ±0.02 mm on outer dimensions and ±0.01 mm on lamination parallelism. Surface roughness Ra 0.4-0.8 um is standard on the working face; grinding to Ra 0.4 um is available. Mounting features (holes, slots, dowel pins) are machined in the same setup so the magnet ships ready to install.

Q4. Can you build a Halbach array as a custom laminated stack?

A. Yes — Halbach is a magnetization pattern, not a material, so it is fully compatible with lamination. Each pole pitch is split into 3-8 segments (typical 4 or 6) with rotated magnetization directions. The segments are precision-ground, oriented, bonded, and magnetized with a multi-pole segmented charging fixture. We can deliver Halbach linear bars, Halbach arc sectors, Halbach rings, and Halbach disc stacks, with or without laminated construction. Standard pole-arc coefficient range is 0.65-0.85; custom patterns (skewed, fractional-slot, concentrated-wound friendly) are quoted on request.

Call to action

Order now to upgrade your high-frequency motor with engineered laminated magnets built to your exact geometry, material, and performance target. For new designs, send your CAD or STEP file, target operating temperature, fundamental switching frequency, magnet grade preference, and any loss or thermal budget. FAIZEAL will return a manufacturability review, a recommended lamination thickness and insulation chemistry, an FEA-based loss estimate, and a quotation. Engineering consultation, prototype samples, and OEM/ODM production are available for qualified projects. Contact FAIZEAL for custom laminated magnets, stacked magnetic steel, and Halbach array magnetic assemblies.