SMZR 32x100 / N52 - magnetic separator with handle

Strengths and weaknesses of neodymium magnets.

Besides their immense pulling force, neodymium magnets offer the following advantages:

• They do not lose power, even after around ten years – the drop in lifting capacity is only ~1% (according to tests),
• Neodymium magnets are characterized by extremely resistant to magnetic field loss caused by external field sources,
• In other words, due to the metallic layer of nickel, the element gains visual value,
• Magnetic induction on the surface of the magnet remains strong,
• 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 modeling and adapting to defined applications,
• Fundamental importance in high-tech industry – they are utilized in mass storage devices, motor assemblies, advanced medical instruments, as well as industrial machines.
• Thanks to their power density, small magnets offer high operating force, in miniature format,

Characteristics of disadvantages of neodymium magnets: weaknesses and usage proposals

• Susceptibility to cracking is one of their disadvantages. Upon intense impact they can fracture. We advise keeping them in a strong case, which not only protects them against impacts but also raises their durability
• Neodymium magnets lose their strength under the influence of heating. As soon as 80°C is exceeded, many of them start losing their force. Therefore, we recommend our special magnets marked [AH], which maintain stability even at temperatures up to 230°C
• They oxidize in a humid environment - during use outdoors we recommend using waterproof magnets e.g. in rubber, plastic
• Due to limitations in realizing threads and complex shapes in magnets, we recommend using cover - magnetic holder.
• Potential hazard resulting from small fragments of magnets are risky, if swallowed, which becomes key in the aspect of protecting the youngest. Additionally, small elements of these devices are able to complicate diagnosis medical in case of swallowing.
• High unit price – neodymium magnets are more expensive than other types of magnets (e.g. ferrite), which hinders application in large quantities

Detachment force of the magnet in optimal conditions – what affects it?

The declared magnet strength concerns the maximum value, obtained under laboratory conditions, specifically:

• on a block made of structural steel, effectively closing the magnetic field
• with a thickness minimum 10 mm
• with a plane cleaned and smooth
• with zero gap (without coatings)
• during detachment in a direction perpendicular to the mounting surface
• in stable room temperature

What influences lifting capacity in practice

Holding efficiency is affected by working environment parameters, mainly (from most important):

• Gap between magnet and steel – even a fraction of a millimeter of separation (caused e.g. by veneer or unevenness) significantly weakens the pulling force, often by half at just 0.5 mm.
• Direction of force – highest force is reached only during pulling at a 90° angle. The resistance to sliding of the magnet along the surface is typically several times lower (approx. 1/5 of the lifting capacity).
• Metal thickness – thin material does not allow full use of the magnet. Part of the magnetic field penetrates through instead of converting into lifting capacity.
• Steel grade – ideal substrate is high-permeability steel. Stainless steels may attract less.
• Plate texture – ground elements guarantee perfect abutment, which increases field saturation. Rough surfaces reduce efficiency.
• Temperature – temperature increase results in weakening of induction. It is worth remembering the maximum operating temperature for a given model.

* Lifting capacity was assessed with the use of a smooth steel plate of suitable thickness (min. 20 mm), under perpendicular detachment force, however under attempts to slide the magnet the holding force is lower. Moreover, even a slight gap {between} the magnet and the plate reduces the load capacity.