SMZR 25x200 / N52 - magnetic separator with handle

Strengths as well as weaknesses of rare earth magnets.

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

• They retain magnetic properties for almost 10 years – the drop is just ~1% (based on simulations),
• Neodymium magnets remain highly resistant to demagnetization caused by external interference,
• By using a decorative layer of silver, the element has an professional look,
• Magnetic induction on the working part of the magnet turns out to be exceptional,
• Thanks to resistance to high temperature, they are able to function (depending on the shape) even at temperatures up to 230°C and higher...
• Thanks to freedom in forming and the capacity to customize to specific needs,
• Key role in innovative solutions – they serve a role in magnetic memories, brushless drives, advanced medical instruments, and complex engineering applications.
• Thanks to efficiency per cm³, small magnets offer high operating force, in miniature format,

Characteristics of disadvantages of neodymium magnets and ways of using them

• At very strong impacts they can crack, therefore we advise placing them in special holders. A metal housing provides additional protection against damage and increases the magnet's durability.
• Neodymium magnets decrease their force 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
• 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
• Limited ability of producing nuts in the magnet and complicated shapes - recommended is a housing - magnetic holder.
• Potential hazard resulting from small fragments of magnets can be dangerous, when accidentally swallowed, which is particularly important in the context of child safety. Additionally, small elements of these products are able to be problematic in diagnostics medical after entering the body.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Maximum lifting capacity of the magnet – what contributes to it?

The specified lifting capacity represents the limit force, measured under laboratory conditions, specifically:

• using a sheet made of high-permeability steel, serving as a ideal flux conductor
• with a cross-section minimum 10 mm
• with a plane free of scratches
• without any insulating layer between the magnet and steel
• under perpendicular application of breakaway force (90-degree angle)
• in stable room temperature

Determinants of practical lifting force of a magnet

Holding efficiency is affected by specific conditions, including (from priority):

• Clearance – the presence of foreign body (paint, tape, gap) interrupts the magnetic circuit, which reduces capacity steeply (even by 50% at 0.5 mm).
• Loading method – catalog parameter refers to detachment vertically. When applying parallel force, the magnet exhibits significantly lower power (often approx. 20-30% of nominal force).
• Base massiveness – too thin steel does not close the flux, causing part of the power to be wasted to the other side.
• Material type – ideal substrate is high-permeability steel. Stainless steels may generate lower lifting capacity.
• Surface condition – ground elements guarantee perfect abutment, which improves field saturation. Rough surfaces weaken the grip.
• Operating temperature – NdFeB sinters have a sensitivity to temperature. At higher temperatures 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 attempts to slide the magnet the lifting capacity is smaller. In addition, even a small distance {between} the magnet’s surface and the plate lowers the load capacity.