SM 32x175 [2xM8] / N42 - magnetic separator

Pros as well as cons of NdFeB magnets.

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

• They have unchanged lifting capacity, and over around 10 years their performance decreases symbolically – ~1% (in testing),
• They do not lose their magnetic properties even under external field action,
• The use of an refined coating of noble metals (nickel, gold, silver) causes the element to be more visually attractive,
• Magnetic induction on the working part of the magnet is very high,
• Due to their durability and thermal resistance, neodymium magnets can operate (depending on the form) even at high temperatures reaching 230°C or more...
• Thanks to flexibility in shaping and the ability to modify to specific needs,
• Versatile presence in future technologies – they serve a role in data components, brushless drives, advanced medical instruments, and other advanced devices.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

What to avoid - cons of neodymium magnets: weaknesses and usage proposals

• To avoid cracks upon strong impacts, we recommend using special steel housings. Such a solution secures the magnet and simultaneously increases its durability.
• We warn that neodymium magnets can reduce their power at high temperatures. To prevent this, we suggest our specialized [AH] magnets, which work effectively even at 230°C.
• Due to the susceptibility of magnets to corrosion in a humid environment, we advise using waterproof magnets made of rubber, plastic or other material immune to moisture, when using outdoors
• We suggest casing - magnetic holder, due to difficulties in realizing nuts inside the magnet and complex shapes.
• Possible danger related to microscopic parts of magnets pose a threat, if swallowed, which becomes key in the context of child safety. Additionally, tiny parts of these devices are able to complicate diagnosis medical after entering the body.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Maximum holding power of the magnet – what contributes to it?

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

• on a block made of mild steel, optimally conducting the magnetic field
• with a cross-section of at least 10 mm
• characterized by lack of roughness
• under conditions of ideal adhesion (metal-to-metal)
• under vertical force direction (90-degree angle)
• in stable room temperature

Determinants of practical lifting force of a magnet

In real-world applications, the actual holding force is determined by several key aspects, presented from crucial:

• Distance – existence of any layer (paint, tape, gap) acts as an insulator, which lowers capacity rapidly (even by 50% at 0.5 mm).
• Pull-off angle – remember that the magnet has greatest strength perpendicularly. Under sliding down, the holding force drops drastically, often to levels of 20-30% of the maximum value.
• Wall thickness – thin material does not allow full use of the magnet. Part of the magnetic field penetrates through instead of generating force.
• Chemical composition of the base – mild steel gives the best results. Alloy admixtures lower magnetic permeability and lifting capacity.
• Smoothness – ideal contact is possible only on smooth steel. Any scratches and bumps reduce the real contact area, reducing force.
• Temperature influence – hot environment weakens magnetic field. Exceeding the limit temperature can permanently damage the magnet.

* Holding force was checked on the plate surface of 20 mm thickness, when the force acted perpendicularly, however under parallel forces the lifting capacity is smaller. Additionally, even a minimal clearance {between} the magnet and the plate reduces the lifting capacity.