FEMm for a voice coil motor

FEMM (Finite Element Method Magnetics) Simulation of High-Performance Voice Coil Actuator. Design Details

* Ring magnets: 5 pieces
* Magnet type: NdFeB ring magnets, N55
* Magnet size: 40 mm OD × 20 mm ID × 10 mm thickness each
* Total magnet stack height: 50 mm
* Magnetization: Axial
* Center pole options to compare:
* 17 mm diameter
* 16 mm diameter
* Magnet inner diameter: 20 mm
* Steel yoke/outer wall: soft magnetic steel / mild steel
* Outer steel wall thickness: approximately 10 mm
* Radial air gap:
* With 17 mm pole: 1.5 mm per side
* With 16 mm pole: 2.0 mm per side

Required Output

* FEMM axisymmetric magnetostatic model
* Magnetic flux lines
* Magnetic field strength in the radial air gap
* Radial flux density Br along the full 50 mm coil length
* Comparison of 17 mm vs 16 mm center pole
* Check for magnetic leakage
* Check for steel saturation
* Suggest simple geometry changes to increase radial gap field
* Provide FEMM files and a short report