SMZR 32x225 / N52 - magnetic separator with handle

Strengths as well as weaknesses of neodymium magnets.

Besides their stability, neodymium magnets are valued for these benefits:

• They retain magnetic properties for around 10 years – the drop is just ~1% (according to analyses),
• They are extremely resistant to demagnetization induced by presence of other magnetic fields,
• A magnet with a metallic silver surface has an effective appearance,
• Neodymium magnets achieve maximum magnetic induction on a small area, which ensures high operational effectiveness,
• Thanks to resistance to high temperature, they can operate (depending on the form) even at temperatures up to 230°C and higher...
• Possibility of exact creating as well as modifying to concrete needs,
• Universal use in advanced technology sectors – they find application in computer drives, brushless drives, precision medical tools, and industrial machines.
• Thanks to efficiency per cm³, small magnets offer high operating force, with minimal size,

What to avoid - cons of neodymium magnets and ways of using them

• Brittleness is one of their disadvantages. Upon strong impact they can break. We advise keeping them in a steel housing, which not only protects them against impacts but also raises their durability
• Neodymium magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop of power (a factor is the shape and dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are very resistant to heat
• Due to the susceptibility of magnets to corrosion in a humid environment, we suggest using waterproof magnets made of rubber, plastic or other material resistant to moisture, in case of application outdoors
• Due to limitations in creating threads and complex shapes in magnets, we propose using cover - magnetic mechanism.
• Possible danger to health – tiny shards of magnets pose a threat, in case of ingestion, which gains importance in the context of child safety. Furthermore, tiny parts of these magnets can be problematic in diagnostics medical after entering the body.
• Due to neodymium price, their price exceeds standard values,

Maximum holding power of the magnet – what it depends on?

Magnet power was defined for ideal contact conditions, taking into account:

• with the use of a yoke made of special test steel, guaranteeing full magnetic saturation
• possessing a thickness of min. 10 mm to ensure full flux closure
• characterized by lack of roughness
• under conditions of gap-free contact (metal-to-metal)
• under perpendicular application of breakaway force (90-degree angle)
• at conditions approx. 20°C

What influences lifting capacity in practice

In real-world applications, the actual holding force depends on a number of factors, listed from most significant:

• Clearance – existence of any layer (paint, tape, gap) acts as an insulator, which reduces power rapidly (even by 50% at 0.5 mm).
• Angle of force application – highest force is available only during perpendicular pulling. The shear force of the magnet along the plate is standardly several times smaller (approx. 1/5 of the lifting capacity).
• Metal thickness – the thinner the sheet, the weaker the hold. Magnetic flux passes through the material instead of generating force.
• Steel grade – ideal substrate is high-permeability steel. Hardened steels may generate lower lifting capacity.
• Plate texture – ground elements guarantee perfect abutment, which improves force. Rough surfaces weaken the grip.
• Thermal environment – heating the magnet causes a temporary drop of induction. It is worth remembering the maximum operating temperature for a given model.

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