Straight answers on coded magnets

A magnet whose face carries a designed pattern of many small magnetic regions rather than a single north and south face. The pattern determines how the magnet behaves — whether it aligns, latches, springs, clicks into positions or releases with a twist.

Not in general, and usually the opposite at a distance. Alternating poles cancel as you move away, so a coded magnet reaches far less than a plain magnet of the same material. On contact it can hold very firmly. You are buying behaviour and a short field, not raw pull.

Because reach is usually what causes trouble. Long-reaching magnets collect swarf and steel debris, interfere with nearby electronics, and grab things you did not intend. A coded magnet does its work on contact and is comparatively inert an inch away.

Usually neodymium, sometimes ferrite. The material sets strength and temperature limit; the pattern sets behaviour. They are independent choices.

Magnetic viewing film shows the pole pattern as a visible image. It is inexpensive and it turns the question into something you can look at.

Yes — that is the point of the technology, and it is also where cost and lead time live. Custom work makes sense at volume or where nothing standard does the job; for one-offs a standard part is usually the better answer.

Under the same conditions as any magnet of that material: heat beyond its operating limit, a strong opposing field, or physical damage. The pattern is magnetisation rather than a coating, so nothing wears off.

When you need long reach, when you need maximum pull for the money, or when a mechanical detent or spring is cheaper and adequate. See the limitations page — it is the honest version of this answer.