SMZR 32x200 / N52 - magnetic separator with handle

Strengths as well as weaknesses of neodymium magnets.

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

• They do not lose power, even over approximately 10 years – the reduction in strength is only ~1% (theoretically),
• They feature excellent resistance to magnetism drop due to external magnetic sources,
• In other words, due to the reflective surface of nickel, the element looks attractive,
• Magnets are characterized by extremely high magnetic induction on the working surface,
• Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and can function (depending on the form) even at a temperature of 230°C or more...
• Thanks to versatility in constructing and the capacity to adapt to complex applications,
• Significant place in future technologies – they find application in HDD drives, electric motors, medical equipment, as well as complex engineering applications.
• Thanks to their power density, small magnets offer high operating force, occupying minimum space,

Disadvantages of NdFeB magnets:

• To avoid cracks under impact, we suggest using special steel housings. Such a solution secures the magnet and simultaneously increases its durability.
• Neodymium magnets decrease their power 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 durability even at temperatures up to 230°C
• Magnets exposed to a humid environment can rust. Therefore while using outdoors, we recommend using water-impermeable magnets made of rubber, plastic or other material resistant to moisture
• Due to limitations in realizing threads and complex shapes in magnets, we propose using cover - magnetic holder.
• Health risk to health – tiny shards of magnets are risky, when accidentally swallowed, which is particularly important in the context of child safety. It is also worth noting that tiny parts of these magnets can be problematic in diagnostics medical after entering the body.
• Due to complex production process, their price is higher than average,

Maximum lifting force for a neodymium magnet – what affects it?

The force parameter is a theoretical maximum value performed under specific, ideal conditions:

• using a plate made of low-carbon steel, serving as a ideal flux conductor
• whose thickness is min. 10 mm
• characterized by even structure
• with direct contact (without impurities)
• during detachment in a direction vertical to the mounting surface
• at standard ambient temperature

Lifting capacity in real conditions – factors

Real force impacted by specific conditions, mainly (from priority):

• Gap between magnet and steel – every millimeter of distance (caused e.g. by varnish or unevenness) diminishes the pulling force, often by half at just 0.5 mm.
• Force direction – declared lifting capacity refers to pulling vertically. When applying parallel force, the magnet holds significantly lower power (often approx. 20-30% of maximum force).
• Element thickness – for full efficiency, the steel must be adequately massive. Thin sheet restricts the lifting capacity (the magnet "punches through" it).
• Metal type – different alloys reacts the same. High carbon content weaken the attraction effect.
• Surface quality – the smoother and more polished the surface, the larger the contact zone and stronger the hold. Roughness acts like micro-gaps.
• Temperature influence – hot environment weakens magnetic field. Exceeding the limit temperature can permanently demagnetize the magnet.

* Holding force was tested on the plate surface of 20 mm thickness, when the force acted perpendicularly, whereas under parallel forces the holding force is lower. Moreover, even a slight gap {between} the magnet’s surface and the plate reduces the holding force.