LM TLN - 15 SQ / N38 - magnetic leviton

Strengths as well as weaknesses of rare earth magnets.

In addition to their long-term stability, neodymium magnets provide the following advantages:

• They retain attractive force for almost 10 years – the loss is just ~1% (in theory),
• Magnets effectively defend themselves against demagnetization caused by external fields,
• In other words, due to the glossy surface of nickel, the element is aesthetically pleasing,
• Magnetic induction on the working layer of the magnet remains strong,
• Thanks to resistance to high temperature, they can operate (depending on the form) even at temperatures up to 230°C and higher...
• Possibility of exact creating and adapting to individual requirements,
• Key role in high-tech industry – they serve a role in mass storage devices, drive modules, advanced medical instruments, also other advanced devices.
• Relatively small size with high pulling force – neodymium magnets offer strong magnetic field in compact dimensions, which enables their usage in small systems

Disadvantages of NdFeB magnets:

• Susceptibility to cracking is one of their disadvantages. Upon strong impact they can fracture. We advise keeping them in a steel housing, which not only protects them against impacts but also raises their durability
• Neodymium magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of power (a factor is the shape as well as dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are very resistant to heat
• Magnets exposed to a humid environment can rust. Therefore while using outdoors, we suggest using water-impermeable magnets made of rubber, plastic or other material resistant to moisture
• We recommend casing - magnetic holder, due to difficulties in producing threads inside the magnet and complex shapes.
• Possible danger resulting from small fragments of magnets can be dangerous, in case of ingestion, which is particularly important in the aspect of protecting the youngest. It is also worth noting that small elements of these magnets can be problematic in diagnostics medical in case of swallowing.
• Due to expensive raw materials, their price exceeds standard values,

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

Breakaway force was determined for optimal configuration, taking into account:

• using a plate made of mild steel, acting as a ideal flux conductor
• with a thickness minimum 10 mm
• with a surface cleaned and smooth
• under conditions of ideal adhesion (metal-to-metal)
• during pulling in a direction vertical to the plane
• in neutral thermal conditions

Magnet lifting force in use – key factors

Real force impacted by working environment parameters, mainly (from most important):

• Space between surfaces – every millimeter of distance (caused e.g. by veneer or dirt) significantly weakens the pulling force, often by half at just 0.5 mm.
• Angle of force application – highest force is obtained only during perpendicular pulling. The resistance to sliding of the magnet along the surface is usually many times smaller (approx. 1/5 of the lifting capacity).
• Wall thickness – the thinner the sheet, the weaker the hold. Magnetic flux penetrates through instead of converting into lifting capacity.
• Steel grade – the best choice is pure iron steel. Hardened steels may have worse magnetic properties.
• Surface condition – ground elements ensure maximum contact, which increases field saturation. Rough surfaces weaken the grip.
• Heat – neodymium magnets have a negative temperature coefficient. When it is hot they lose power, and at low temperatures gain strength (up to a certain limit).

* Lifting capacity was assessed by applying a polished steel plate of optimal thickness (min. 20 mm), under perpendicular detachment force, however under parallel forces the load capacity is reduced by as much as 75%. Additionally, even a small distance {between} the magnet and the plate lowers the lifting capacity.