Design & DFM Resources
AFPM Core Design Checklist
Use this AFPM (axial flux permanent magnet) core design checklist to score electromagnetic, structural, thermal, and manufacturing risks before committing to expensive tooling.
Evidence reviewed July 29, 2026. Source dates and limitations are listed below the assessor before any tooling decision.
- 13
- readiness checks
- 6
- critical gates
- 6
- reviewed sources
Critical Design Guardrails
Evidence Ledger and Method Flow
Use the workflow after the assessor: close critical gates, attach evidence IDs, then decide whether the design is ready for RFQ, prototype, or rework.
Traceable Source Ledger
Dates show when the source was reviewed for this page; vendor PDFs and design centers can change without notice.
| ID | Source | Used For | Reviewed |
|---|---|---|---|
| S1 | Hoganas - Somaloy powder solutions for SMC applications | Supports SMC motor-core positioning, 3D magnetic behavior, near-net-shape PM process fit, and supplier-specific DFM review. | July 29, 2026 |
| S2 | JMAG International and Hoganas - SMC in motor design | Supports the warning that SMC core design should be evaluated with motor simulation and material data rather than steel-core assumptions. | July 29, 2026 |
| S3 | Hoganas - Somaloy 3P material data | Benchmarks published SMC material properties used as screening context; buyer geometry still requires project-specific test coupons. | July 29, 2026 |
| S4 | Metal Powder Industries Federation - Design Resource Center | Provides powder-metallurgy design framing for pressing, ejection, tolerances, and manufacturability review. | July 29, 2026 |
| S5 | AxialFluxCore - AFPM thermal management and cooling guide | Internal evidence layer for heat-path, potting, direct cooling, and thermal validation questions. | July 22, 2026 |
| S6 | AxialFluxCore - manufacturing quality evidence | Internal supplier-quality lens for dimensional inspection, first-article review, and RFQ evidence handoff. | July 29, 2026 |
Risks, Limits, and Mitigations
| Risk | Impact | Likelihood | Mitigation |
|---|---|---|---|
| Using the checklist as final design approval | High | Medium | Treat the score as a readiness screen; release only after FEA, samples, inspection, and supplier DFM evidence agree. |
| SMC route chosen for a steel-like geometry | Medium | Medium | Compare SMC and laminated routes with the same torque, frequency, tolerance, and validation basis. |
| Critical air-gap and axial-load evidence missing | High | Medium | Add stiffness, runout, bearing growth, thermal expansion, and debris clearance checks before prototype release. |
| Tooling CAPEX committed before DFM closure | High | High | Use coupons, segmented samples, or soft tooling until draft, density, wall thickness, and inspection datums are signed off. |
Engineering Action Plan
1. Electromagnetic Validation
- Confirm 3D FEA solver is used for flux path analysis.
- Verify iron losses at maximum operating frequency (e.g., > 400Hz).
- Check local flux density to ensure no deep saturation (< 1.8T for SMC).
2. Mechanical & Structural
- Calculate static and dynamic axial attractive forces.
- Set air gap tolerances and verify housing/bearing stiffness.
- Define core retention mechanisms (clamping, potting, overmolding).
3. Thermal Analysis
- Account for actual material thermal conductivity.
- Simulate peak continuous torque temperature at the winding-tooth interface.
- Design cooling path (e.g., water jacket, direct oil cooling).
4. Manufacturing (DFM)
- Verify supplier-specific draft, wall-thickness, ejection, and secondary-operation limits.
- Screen length-to-wall-thickness ratio and density gradients with supplier DFM input.
- Plan segmentation when press capacity, density uniformity, or air-gap control cannot be proven.
- Perform tolerance stack-up analysis for the complete assembly.
Simulation vs. Reality Limits
Electromagnetic predictions
Known:The checklist covers essential simulation steps like 3D FEA and saturation limits.
Unknown:Actual B-H curve variations due to specific local compaction densities.
Action:Validate with physical samples; do not rely purely on nominal datasheet curves.
Mechanical deflection
Known:Axial forces can be calculated statically.
Unknown:Dynamic resonances and housing compliance under thermal expansion.
Action:Perform full structural-thermal-magnetic coupled analysis.
SMC Compaction Integrity
Known:Overall bulk component density and average permeability.
Unknown:Local density drops at deep tooth roots and microscopic insulation coating breakage from over-compaction.
Action:Perform 3D density mapping simulation or request segmented test pieces from PM supplier.
Ready for supplier-specific AFPM core review?
Send CAD, material route, duty cycle, tolerance stack, and the checklist gaps so AxialFluxCore can screen SMC tooling, inspection, and prototype risk before RFQ release.