Engineering Perspective
Stop forcing three-dimensional magnetic circuits into two-dimensional manufacturing rules.
Let’s stop thinking in 2D when 3D is a viable alternative.
For decades, motor design has been shaped by the electrical steel sheet: thin laminations stacked into structures that carry magnetic flux primarily within the plane of each layer. That manufacturing approach has influenced the geometries engineers can practically build.
Soft Magnetic Composites (SMC) expand those possibilities. Their magnetically isotropic nature means they have similar magnetic properties in every direction, supporting 360 degrees of magnetic flux. That gives engineers greater freedom to rethink core geometry, winding placement, and how the magnetic circuit fits within the available space.
Why keep forcing three-dimensional magnetic designs into two-dimensional manufacturing rules when the material can support the flux path you actually want?
For more than a century, laminated electrical steel has been one of the most successful enabling technologies in electric machine design. Stamp a two-dimensional profile, stack it, keep the working flux in the plane, and you get a repeatable magnetic circuit that industry knows how to manufacture at scale.
That manufacturing logic became so familiar that it started to look like a law of motor design. But the sheet defined the boundaries - not the physics.
When an application requires flux to travel axially, return circumferentially, or move between discrete stator segments, forcing that magnetic circuit into a lamination stack adds manufacturing complexity. The core becomes a puzzle of stamped pieces, joints, welds, stacking directions, and secondary operations simply because the original material form prefers a flat path.
That is the real importance of 3D flux. It does not simply give the magnetic field another direction. It gives the engineer permission to design the magnetic circuit around the application instead of around the sheet.
DIRECT ANSWER: Three-dimensional flux paths change motor design because they decouple magnetic geometry from the lamination plane. In machines with deliberately multidirectional working flux, SMC should be evaluated as a baseline material, not as a late-stage substitute. The mistake is not using laminations. The mistake is assuming laminations must remain the default after the physics has moved beyond 2D.
Electrical steel is excellent at what it was designed to do: carry magnetic flux efficiently in the plane of a thin sheet while controlling eddy-current loss utilizing the Steinmetz equation. The industry then built tooling, joining methods, winding processes, inspection systems, and supply chains around that format.
But the lamination stack is not only a material choice. It is a geometric rule. Tooth shape, pole geometry, return path, winding access, joining method, and assembly sequence are all influenced by the requirement that the magnetic component begins as a stamped two-dimensional profile.
Where flux is predominantly planar, that rule can be an advantage. High permeability, thin-gauge electrical steel, and mature production can make laminations exceptionally difficult to beat.
Where the useful flux is not planar, preserving the stack can become an exercise in protecting the manufacturing method instead of optimizing the machine.
Figure 1. Laminated electrical steel is optimized around in-plane flux and stacked geometry. SMC allows multidirectional working flux and net shape magnetic components to be designed together.
A three-dimensional flux path is a useful magnetic circuit in which flux travels through multiple spatial directions within the working path. Radial, axial, and circumferential components may all appear as flux moves through the stator, rotor, air gap, poles, and return path.
That distinction matters because a lamination is directionally optimized. Flux traveling within the sheet plane sees the material in the way the stack was intended to operate. Flux that must cross the stack encounters a different magnetic path, more interfaces, and a geometry that is often difficult to stamp and assemble cleanly.
Soft Magnetic Composites (SMC) change that relationship. Each iron particle is electrically insulated before compaction, producing bulk magnetic behavior that supports useful flux in multiple directions while suppressing large eddy-current loops. Just as important, powder compaction makes net shape three-dimensional magnetic components a practical production strategy rather than a prototyping workaround.
ENGINEERING POSITION: SMC is not simply an alternative core material for a 3D-flux machine. In many architectures, it is the material that makes the intended magnetic circuit manufacturable in the first place.
Once the magnetic material is no longer tied to a repeated flat profile, geometry becomes part of the electromagnetic solution. Engineers can consider tapered teeth, shaped pole faces, claw-pole features, discrete stator segments, curved return paths, variable cross-sections, and locally optimized flux areas.
The point is not complexity for its own sake. A new shape should earn its place by solving a measurable problem: reduce a saturation bottleneck, shorten a magnetic path, improve magnet utilization, open winding access, reduce end-turn length, lower part count, improve package fit, or move heat more effectively.
The disruptive idea is simple: magnetic geometry no longer has to begin with the question, "Can this be stamped?"
Three-dimensional magnetic capability becomes especially valuable when the motor topology itself depends on flux turning through multiple axes or on magnetic parts that do not repeat naturally through a stack.
A lamination stack often forces the winding process to work around a completed stator. Discrete SMC teeth can reverse that sequence. Coils can be wound offline as individual manufacturing units, slid onto the magnetic component, inspected before final assembly, and integrated into a segmented stator architecture.
That improves copper placement, winding access, automation, and assembly repeatability. In axial-flux concepts, the combination of net shape teeth and pre-wound coils is particularly powerful because the magnetic and copper geometry can be developed together rather than as separate compromises.
This is not a secondary manufacturing benefit. Copper utilization, slot fill, end-turn length, insulation strategy, and cooling all influence torque density and efficiency. Change the core geometry and the winding problem changes with it.
With SMC, engineers can design the core around the intended three-dimensional flux path and work with manufacturing specialists to make that geometry practical to produce.
That opens opportunities to integrate features, simplify assembly, and use the available space more effectively. Material selection, core geometry, and winding placement can be developed together, with both performance and production in mind.
Net shape powder metallurgy brings those choices into a repeatable process suited to high-volume production. The value is - creating a component whose shape serves both the magnetic circuit and optimization of the manufacturing process.
Not every motor needs a three-dimensional magnetic circuit. But a design team should not discover that by defaulting to laminations. It should make the decision deliberately.
The Horizon 3D Flux Opportunity Gates provide a practical sequence for deciding whether a 3D-flux concept deserves serious development.
SMC content is often framed around a cautious question: where can SMC fit? That question is too passive for a material that changes the design space.
There are applications where beginning with laminations is likely to make the design harder than it needs to be. SMC should be one of the first material-topology combinations modeled when several of the following conditions are present:
In those cases, SMC should not be evaluated after the laminated concept has been optimized and frozen. It should be part of the baseline architecture comparison from the beginning.
Laminated electrical steel remains an exceptional technology when the machine is fundamentally two-dimensional. If the working flux is overwhelmingly in-plane, low-frequency magnetic loading dominates, and the stack geometry is already highly optimized for production, laminations can still be the strongest engineering answer.
That is not a reason to stay neutral. It is the boundary condition.
The mistake is carrying a two-dimensional manufacturing answer into an architecture that deliberately leaves the plane, then spending time and cost rebuilding the 3D magnetic circuit from stamped parts.
Traditional motor development often follows the material form: choose the familiar core construction, build a manufacturable geometry around it, and then optimize the electromagnetic design within those boundaries.
A 3D flux path is a useful magnetic circuit in which working flux travels through multiple spatial directions, such as radial, axial, and circumferential paths, rather than remaining primarily within one plane.
Electrical steel laminations are thin insulated sheets designed to control eddy currents. They perform best when useful flux remains in the sheet plane. Cross-plane flux encounters a less favorable magnetic path and often requires complex stacking or assembly to create three-dimensional geometry.
SMC should be evaluated early when the useful flux is intentionally multidirectional, when the topology depends on 3D teeth or poles, when segmentation or pre-wound coils create system value, or when net shape geometry can replace a complicated lamination assembly.
No. Efficiency depends on topology, material grade, flux density, frequency, waveform, winding design, thermal conditions, and duty cycle. The stronger case for SMC is not a universal efficiency claim. It is the ability to enable architectures and manufacturing strategies that laminations cannot realize as effectively.
Transverse-flux, claw-pole, yokeless axial-flux, segmented-stator, and other machines with intentionally multidirectional magnetic circuits are natural candidates. SMC can also create value in selected radial-flux designs when geometry, high-frequency behavior, or integrated manufacturing justify it.
Net shape means the magnetic component is compacted directly to the intended functional geometry rather than being built from multiple stamped layers and then extensively machined into shape. Secondary operations may still be used when tolerances or features require them, but the magnetic geometry is created by the compaction process itself.
Yes. There are architectures where laminations remain useful in strongly planar regions while SMC is used where flux turns or geometry becomes three-dimensional. The point is not to preserve both materials equally. The point is to put each material where it creates the greatest system value.
DESIGN THE MAGNETIC CIRCUIT BEFORE YOU INHERIT THE MANUFACTURING CONSTRAINT.
If your team is evaluating a motor with deliberate 3D flux, complex stator geometry, segmentation, or a production route that is becoming harder than the magnetic problem itself, bring material and manufacturing strategy into the design review early.
Ready to evaluate your motor concept? Share your project details with Horizon Technology for an engineering review of the geometry, material, and manufacturing path.