ZM XMAG2 105 elementów - magnetic toy

Pros as well as cons of neodymium magnets.

In addition to their magnetic capacity, neodymium magnets provide the following advantages:

• They retain attractive force for nearly ten years – the loss is just ~1% (in theory),
• They retain their magnetic properties even under close interference source,
• By covering with a lustrous coating of silver, the element has an professional look,
• The surface of neodymium magnets generates a strong magnetic field – this is a distinguishing feature,
• Due to their durability and thermal resistance, neodymium magnets can operate (depending on the form) even at high temperatures reaching 230°C or more...
• Possibility of custom shaping as well as adapting to defined applications,
• Wide application in innovative solutions – they find application in magnetic memories, electric motors, medical equipment, and modern systems.
• Relatively small size with high pulling force – neodymium magnets offer strong magnetic field in compact dimensions, which enables their usage in compact constructions

Disadvantages of NdFeB magnets:

• To avoid cracks under impact, we recommend using special steel holders. Such a solution protects the magnet and simultaneously increases its durability.
• Neodymium magnets decrease their force under the influence of heating. As soon as 80°C is exceeded, many of them start losing their power. Therefore, we recommend our special magnets marked [AH], which maintain stability even at temperatures up to 230°C
• Magnets exposed to a humid environment can rust. Therefore when using outdoors, we advise using waterproof magnets made of rubber, plastic or other material resistant to moisture
• Limited possibility of creating threads in the magnet and complicated shapes - preferred is casing - magnetic holder.
• Health risk resulting from small fragments of magnets can be dangerous, in case of ingestion, which becomes key in the context of child health protection. Furthermore, small elements of these devices are able to be problematic in diagnostics medical when they are in the body.
• High unit price – neodymium magnets have a higher price than other types of magnets (e.g. ferrite), which increases costs of application in large quantities

Best holding force of the magnet in ideal parameters – what affects it?

Information about lifting capacity is the result of a measurement for ideal contact conditions, assuming:

• using a base made of low-carbon steel, functioning as a ideal flux conductor
• whose transverse dimension equals approx. 10 mm
• with an ideally smooth touching surface
• without the slightest insulating layer between the magnet and steel
• for force applied at a right angle (in the magnet axis)
• in neutral thermal conditions

Practical lifting capacity: influencing factors

It is worth knowing that the magnet holding will differ subject to elements below, in order of importance:

• Space between surfaces – every millimeter of separation (caused e.g. by varnish or dirt) significantly weakens the magnet efficiency, often by half at just 0.5 mm.
• Angle of force application – maximum parameter is available only during perpendicular pulling. The shear force of the magnet along the surface is standardly several times lower (approx. 1/5 of the lifting capacity).
• Element thickness – for full efficiency, the steel must be adequately massive. Thin sheet restricts the attraction force (the magnet "punches through" it).
• Material type – the best choice is high-permeability steel. Cast iron may generate lower lifting capacity.
• Plate texture – ground elements ensure maximum contact, which improves field saturation. Uneven metal weaken the grip.
• Heat – neodymium magnets have a sensitivity to temperature. At higher temperatures they lose power, and at low temperatures gain strength (up to a certain limit).

* Lifting capacity was assessed with the use of a steel plate with a smooth surface of optimal thickness (min. 20 mm), under vertically applied force, in contrast under attempts to slide the magnet the lifting capacity is smaller. Moreover, even a minimal clearance {between} the magnet and the plate reduces the holding force.