Which magnet does what?

A coded twist-release magnet. The Polymagnet twist-release pair (part 1002300) attracts about 49 N when aligned at 0° and actively repels — about 57 N — at ±20°, so it holds firm, then ejects on a quarter-turn. It’s the exact part NASA flew on its Prandtl-M glider, and the one the SmarterEveryDay video made famous.

Yes — a coded spring or standoff magnet (Polymagnet 1002288). Two spatial frequencies in one face make the pair float at a designed gap: it pushes back about 25 N near contact and fades to zero by roughly 15 mm. A contactless spring with nothing to fatigue, corrode or house. It needs a pin for lateral constraint — it is not levitation.

Use coded alignment pairs. A rotational or center-alignment pattern pulls two parts into one exact position or angle and pushes back everywhere else, so an assembly seats itself the same way every time. They come in #4/#6/M4 countersunk mounts that bolt straight into a part, and bi-directional versions add two-way shear resistance.

Yes — a coded detent magnet. Sector-patterned pairs give discrete click positions — 4, 6 or 12 per turn — like a rotary switch, with nothing mechanical inside to wear out. The feel of a well-made dial, printed into the magnet.

A coded latch magnet. Push-to-close and spring-latch patterns pull a lid or drawer closed on contact — and a spring pattern can push it back — giving a latch or spring action with no coil, no hinge and no wear. The parts behind a lid that closes itself.

A single piece of ordinary neodymium whose face has been magnetized into a designed pattern of many small north and south regions — so its behavior (grip, push, align, click, release) is written into the pattern rather than the material. The same blank can be made to do different jobs by changing only the pattern. Correlated Magnetics Research invented the technology and trademarked it as Polymagnet.

A maxel is a “magnetic pixel” — one small poled region, roughly 1–4 mm across, written independently of its neighbors. A coded magnet is made of many maxels arranged in a pattern, the way an image is made of many pixels. Change the arrangement, change what the magnet does.

No. Earnshaw’s theorem rules out stable levitation with fixed permanent magnets, and Correlated Magnetics says so plainly: every coded “magnetic spring” demonstration rides on a pin or shaft for lateral constraint. Coded magnets are contact and near-contact devices — strong at the surface, nearly dead an inch away. For true levitation you need superconductors or active electromagnets, not a coded permanent magnet.

With a magnetizing printer. A computer-controlled head fires a short current pulse — about 0.8 ms — through a coil focused by a roughly 1 mm aperture, writing one maxel at a time onto an ordinary magnet blank, then steps and fires again. A dot-matrix printer for magnetism: changing the design just changes the file, so the same blank becomes a latch, a spring or a key.

Through the Whole Magnetics Catalog shop, organized by what each part does. Demo kits and coded-magnet parts ship via FerroSpring (a Polymagnet distributor); custom parts come from the source, Correlated Magnetics Research. Start with the Demo Kit if you want to feel the behaviors before you design them in.

Free: FEMM for 2D and axisymmetric fields, Magpylib (Python) for fast analytical fields and Halbach arrays, and Radia for 3D undulator, Halbach and multipole accelerator magnets. Commercial: ANSYS Maxwell and COMSOL for full 3D arbitrary magnetization. For a quick holding-force estimate, the free K&J Magnetics web calculators.

For a general reader, Driving Force: The Natural Magic of Magnets by James D. Livingston — the great readable one. For engineering reference, J. M. D. Coey’s Magnetism and Magnetic Materials; for multipole and patterned-magnet design specifically, Furlani’s Permanent Magnet and Electromechanical Devices and Tanabe’s Iron-Dominated Electromagnets.