FM Ruszt magnetyczny do leja fi 200 jednopoziomowy / N52 - magnetic filter

Strengths as well as weaknesses of NdFeB magnets.

Besides their tremendous magnetic power, neodymium magnets offer the following advantages:

• They have constant strength, and over more than ten years their performance decreases symbolically – ~1% (in testing),
• They maintain their magnetic properties even under external field action,
• The use of an aesthetic coating of noble metals (nickel, gold, silver) causes the element to be more visually attractive,
• Magnetic induction on the top side of the magnet turns out to be maximum,
• Thanks to resistance to high temperature, they are capable of working (depending on the form) even at temperatures up to 230°C and higher...
• Thanks to the option of precise shaping and adaptation to unique solutions, NdFeB magnets can be produced in a wide range of forms and dimensions, which expands the range of possible applications,
• Significant place in electronics industry – they serve a role in computer drives, electromotive mechanisms, advanced medical instruments, and technologically advanced constructions.
• Thanks to their power density, small magnets offer high operating force, with minimal size,

Disadvantages of neodymium magnets:

• To avoid cracks upon strong impacts, we recommend using special steel holders. Such a solution protects the magnet and simultaneously increases its durability.
• Neodymium magnets lose their force 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
• Due to the susceptibility of magnets to corrosion in a humid environment, we recommend using waterproof magnets made of rubber, plastic or other material resistant to moisture, when using outdoors
• Due to limitations in realizing threads and complicated shapes in magnets, we propose using casing - magnetic mechanism.
• Potential hazard related to microscopic parts of magnets pose a threat, when accidentally swallowed, which gains importance in the context of child safety. Furthermore, small components of these magnets can be problematic in diagnostics medical after entering the body.
• High unit price – neodymium magnets cost more than other types of magnets (e.g. ferrite), which can limit application in large quantities

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

The declared magnet strength refers to the peak performance, measured under ideal test conditions, meaning:

• on a block made of mild steel, effectively closing the magnetic field
• possessing a massiveness of minimum 10 mm to ensure full flux closure
• characterized by lack of roughness
• under conditions of no distance (surface-to-surface)
• under perpendicular force direction (90-degree angle)
• in stable room temperature

Determinants of lifting force in real conditions

Effective lifting capacity is influenced by specific conditions, such as (from most important):

• Air gap (betwixt the magnet and the plate), since even a tiny clearance (e.g. 0.5 mm) results in a drastic drop in force by up to 50% (this also applies to varnish, corrosion or dirt).
• Pull-off angle – note that the magnet has greatest strength perpendicularly. Under sliding down, the capacity drops drastically, often to levels of 20-30% of the nominal value.
• Element thickness – to utilize 100% power, the steel must be adequately massive. Paper-thin metal limits the attraction force (the magnet "punches through" it).
• Steel grade – ideal substrate is pure iron steel. Cast iron may generate lower lifting capacity.
• Smoothness – full contact is possible only on smooth steel. Any scratches and bumps reduce the real contact area, weakening the magnet.
• Thermal environment – temperature increase results in weakening of induction. Check the maximum operating temperature for a given model.

* Lifting capacity testing was carried out on plates with a smooth surface of suitable thickness, under a perpendicular pulling force, in contrast under shearing force the holding force is lower. Moreover, even a small distance {between} the magnet and the plate reduces the holding force.