Glossary
The working vocabulary.
Every term this site (and the vendor literature) leans on, in plain engineering English.
- maxel
- a magnetic pixel — one small printed N or S region, roughly 1–4 mm, the unit a pattern is built from.
- magnetic code
- the designed arrangement of maxels on a face; the code determines the force function.
- correlation
- the mathematics of how two coded faces interact — force tracks the spatial correlation of their codes, peaking at exact alignment like a matched filter.
- correlated magnetics
- CMR's name for the discipline: applying signal-processing code design (from UWB radar) to magnetization patterns.
- field emission structure
- the patents' term for a coded magnetic surface (see cornerstone patent US 7,800,471).
- spatial force function
- the engineered force-versus-position curve of a coded pair — the thing that becomes a design variable.
- multipole
- any magnet with more than one pole pair on a face — from simple alternating fridge strips and ABS encoder rings to fully coded surfaces.
- Halbach array
- a periodic rotating-magnetization arrangement that concentrates flux on one side; motors, MRI, maglev. Engineered magnetization's older sibling (Mallinson 1973, Halbach 1980s).
- near field / far field
- close to a patterned face the field is intense; it decays exponentially (F ∝ e^(−2πz/λ), λ = pole pitch) so the far field can be engineered toward zero.
- Polymagnet®
- CMR's product brand for coded magnets.
- MagPrinter
- CMR's magnetizing printer — a computer-controlled head writing ~1 mm maxels with ~0.8 ms pulses; first shipped 2013.
- Barker code
- a short binary sequence with minimal autocorrelation sidelobes, borrowed from radar; used in the patents to give magnet pairs sharp, unambiguous alignment force.
- spring / latch / align / twist-release / attach / shear / torque / detent
- CMR's catalog behaviors — see the behavior explorer for each mechanism and its numbers.
- Earnshaw's theorem
- no arrangement of static magnets can stably levitate — why every magnetic-spring demo runs on a constraining pin.
- energy product (MGOe)
- the figure of merit for magnet material strength; NdFeB tops out around 52 MGOe. Coding redistributes this energy; it cannot add to it.
- electropermanent magnet
- a magnet switched on/off by a current pulse but requiring no power to hold — 'programmable in time' (Magswitch and peers), versus coded magnets' 'programmable in space.'
- poka-yoke
- error-proofing; in magnetics, keyed coded pairs that physically refuse wrong assembly.
- MR-Conditional
- a device demonstrated safe in MRI under stated conditions — what rotatable implant magnet design achieved for cochlear implants.
- holding force vs. breakaway force
- the static pull a magnet exerts on a mating surface (holding) versus the force needed to shear or peel it off (breakaway) — usually much lower. Datasheets quote holding; assembly cares about breakaway.
- shear force
- force parallel to the contact face. Coded pairs can be tuned for high shear at a given normal force — the vendor cites 2–8× a plain magnet, though independent shear data is unpublished.
- remanence (Br)
- the flux density a magnet retains with no external field — a raw-material property (NdFeB ≈ 1.0–1.4 T). Coding rearranges where that flux emerges; it does not raise Br.
- coercivity (Hcj)
- a material’s resistance to demagnetization. High-Hcj grades (and SmCo) hold their pattern at higher temperature — the number to check for hot applications.
- temperature coefficient
- the reversible loss of strength per °C of heating (NdFeB ≈ −0.11%/°C). Above the rated temperature, loss becomes irreversible — why standard ~60 °C parts need re-spec for hot environments.
- Curie temperature
- the temperature at which a magnet loses magnetization entirely (NdFeB ≈ 310–400 °C). The safe working limit is far below it, set by coercivity and geometry.
- pole pitch (λ)
- the center-to-center spacing of alternating poles in a pattern. It sets the near-field decay length: finer pitch = stronger surface field but faster fall-off (F ∝ e^(−2πz/λ)).
- gauss / tesla
- units of magnetic flux density (1 T = 10,000 G). Surface-field gauss readings from a gauss meter are a common but incomplete proxy — a coded face’s force depends on the pattern, not a single gauss number.
- pull test
- the standard measurement of holding force, pulling a magnet straight off a thick steel plate. Coded and Halbach parts must be tested on the intended target (thin steel, another coded face) to mean anything.
- keeper
- a soft-iron bar placed across a magnet’s poles to close the flux path in storage. Less relevant to fine-pattern coded magnets, whose flux already closes locally at the surface.
- attenuated / contained field
- a pattern engineered so the field collapses toward zero a few millimetres away — the property that lets coded magnets work next to cards, compasses and Hall sensors.
- duty cycle (switchable magnets)
- for electropermanent and switchable tooling, the ratio of switching events to hold time. These hold with zero standby power and draw current only to switch — the figure that drives their energy case.
Mechanism-level definitions with diagrams live at the companion encyclopedia, multipolemag.com.