SMZR 32x225 / N52 - magnetic separator with handle

Strengths and weaknesses of NdFeB magnets.

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

• They have unchanged lifting capacity, and over nearly ten years their attraction force decreases symbolically – ~1% (in testing),
• They are extremely resistant to demagnetization induced by external field influence,
• By using a smooth coating of gold, the element gains an nice look,
• Magnets possess extremely high magnetic induction on the working surface,
• Thanks to resistance to high temperature, they can operate (depending on the shape) even at temperatures up to 230°C and higher...
• In view of the ability of free forming and adaptation to unique needs, NdFeB magnets can be manufactured in a wide range of geometric configurations, which makes them more universal,
• Significant place in innovative solutions – they are commonly used in computer drives, brushless drives, advanced medical instruments, and modern systems.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

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

• At strong impacts they can break, therefore we advise placing them in strong housings. A metal housing provides additional protection against damage and increases the magnet's durability.
• Neodymium magnets decrease their power under the influence of heating. As soon as 80°C is exceeded, many of them start losing their power. 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 corrode. Therefore during using outdoors, we recommend using waterproof magnets made of rubber, plastic or other material protecting against moisture
• Due to limitations in realizing nuts and complicated forms in magnets, we recommend using casing - magnetic holder.
• Potential hazard to health – tiny shards of magnets can be dangerous, in case of ingestion, which gains importance in the aspect of protecting the youngest. It is also worth noting that small elements of these devices are able to disrupt the diagnostic process medical after entering the body.
• Due to neodymium price, their price is higher than average,

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

The load parameter shown refers to the limit force, obtained under ideal test conditions, namely:

• on a base made of structural steel, optimally conducting the magnetic field
• with a cross-section of at least 10 mm
• with an ground touching surface
• under conditions of gap-free contact (metal-to-metal)
• under perpendicular force vector (90-degree angle)
• in temp. approx. 20°C

Practical lifting capacity: influencing factors

Please note that the working load may be lower influenced by the following factors, starting with the most relevant:

• Space between magnet and steel – even a fraction of a millimeter of distance (caused e.g. by veneer or unevenness) drastically reduces the magnet efficiency, often by half at just 0.5 mm.
• Load vector – highest force is available only during perpendicular pulling. The shear force of the magnet along the surface is typically several times smaller (approx. 1/5 of the lifting capacity).
• Substrate thickness – for full efficiency, the steel must be sufficiently thick. Paper-thin metal limits the attraction force (the magnet "punches through" it).
• Metal type – different alloys attracts identically. High carbon content weaken the interaction with the magnet.
• Plate texture – smooth surfaces ensure maximum contact, which improves field saturation. Rough surfaces weaken the grip.
• Heat – NdFeB sinters have a sensitivity to temperature. When it is hot they lose power, and in frost gain strength (up to a certain limit).

* Lifting capacity testing was carried out on plates with a smooth surface of suitable thickness, under a perpendicular pulling force, in contrast under attempts to slide the magnet the load capacity is reduced by as much as 5 times. Additionally, even a minimal clearance {between} the magnet’s surface and the plate decreases the lifting capacity.