SMZR 25x200 / N52 - magnetic separator with handle

Advantages and disadvantages of NdFeB magnets.

In addition to their pulling strength, neodymium magnets provide the following advantages:

• Their power is maintained, and after approximately ten years it drops only by ~1% (theoretically),
• They have excellent resistance to weakening of magnetic properties due to external fields,
• Thanks to the shimmering finish, the layer of Ni-Cu-Ni, gold, or silver-plated gives an clean appearance,
• Neodymium magnets generate maximum magnetic induction on a their surface, which ensures high operational effectiveness,
• Through (adequate) combination of ingredients, they can achieve high thermal resistance, allowing for action at temperatures reaching 230°C and above...
• Thanks to the option of accurate shaping and customization to specialized needs, neodymium magnets can be modeled in a wide range of forms and dimensions, which increases their versatility,
• Wide application in modern industrial fields – they serve a role in HDD drives, electromotive mechanisms, diagnostic systems, as well as other advanced devices.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• To avoid cracks under impact, we suggest using special steel holders. Such a solution secures the magnet and simultaneously increases its durability.
• We warn that neodymium magnets can lose their strength at high temperatures. To prevent this, we recommend our specialized [AH] magnets, which work effectively even at 230°C.
• When exposed to humidity, magnets usually rust. For applications outside, it is recommended to use protective magnets, such as those in rubber or plastics, which prevent oxidation as well as corrosion.
• Limited ability of producing threads in the magnet and complicated shapes - recommended is cover - magnet mounting.
• Health risk to health – tiny shards of magnets are risky, when accidentally swallowed, which is particularly important in the context of child safety. Furthermore, small elements of these magnets can be problematic in diagnostics medical when they are in the body.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

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

Magnet power was defined for ideal contact conditions, including:

• on a plate made of structural steel, optimally conducting the magnetic field
• with a thickness minimum 10 mm
• with a plane cleaned and smooth
• without the slightest clearance between the magnet and steel
• under axial force vector (90-degree angle)
• at standard ambient temperature

Practical lifting capacity: influencing factors

In practice, the actual lifting capacity depends on many variables, presented from crucial:

• Distance (between the magnet and the metal), as even a microscopic clearance (e.g. 0.5 mm) results in a decrease in lifting capacity by up to 50% (this also applies to varnish, corrosion or debris).
• Direction of force – maximum parameter is reached only during perpendicular pulling. The resistance to sliding of the magnet along the plate is standardly many times smaller (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 type – mild steel attracts best. Alloy admixtures lower magnetic properties and lifting capacity.
• Surface finish – full contact is possible only on polished steel. Rough texture create air cushions, weakening the magnet.
• Thermal conditions – neodymium magnets have a sensitivity to temperature. When it is hot they are weaker, and in frost gain strength (up to a certain limit).

* Holding force was tested on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, however under shearing force the holding force is lower. In addition, even a small distance {between} the magnet and the plate decreases the lifting capacity.