SM 25x350 [2xM8] / N52 - magnetic separator

Advantages as well as disadvantages of neodymium magnets.

Besides their remarkable pulling force, neodymium magnets offer the following advantages:

• They do not lose power, even after nearly 10 years – the drop in strength is only ~1% (according to tests),
• They show high resistance to demagnetization induced by external field influence,
• A magnet with a metallic gold surface is more attractive,
• The surface of neodymium magnets generates a powerful magnetic field – this is a key feature,
• Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and can function (depending on the shape) even at a temperature of 230°C or more...
• Possibility of detailed machining as well as adapting to defined conditions,
• Wide application in electronics industry – they are utilized in magnetic memories, motor assemblies, advanced medical instruments, and industrial machines.
• Thanks to concentrated force, small magnets offer high operating force, with minimal size,

Disadvantages of neodymium magnets:

• To avoid cracks under impact, we suggest using special steel housings. Such a solution protects the magnet and simultaneously improves its durability.
• NdFeB 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 extremely resistant to heat
• They rust in a humid environment - during use outdoors we advise using waterproof magnets e.g. in rubber, plastic
• Limited possibility of producing threads in the magnet and complex forms - recommended is cover - magnet mounting.
• Health risk related to microscopic parts of magnets pose a threat, when accidentally swallowed, which becomes key in the context of child safety. It is also worth noting that small elements of these devices can be problematic in diagnostics medical after entering the body.
• With large orders the cost of neodymium magnets can be a barrier,

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

Information about lifting capacity was determined for ideal contact conditions, including:

• on a block made of structural steel, perfectly concentrating the magnetic flux
• whose transverse dimension is min. 10 mm
• with a surface cleaned and smooth
• without the slightest clearance between the magnet and steel
• under axial application of breakaway force (90-degree angle)
• in stable room temperature

What influences lifting capacity in practice

Bear in mind that the magnet holding may be lower subject to elements below, starting with the most relevant:

• Distance (between the magnet and the metal), as even a tiny clearance (e.g. 0.5 mm) results in a reduction in lifting capacity by up to 50% (this also applies to paint, rust or debris).
• Loading method – declared lifting capacity refers to detachment vertically. When slipping, the magnet exhibits significantly lower power (often approx. 20-30% of maximum force).
• Element thickness – to utilize 100% power, the steel must be adequately massive. Thin sheet limits the lifting capacity (the magnet "punches through" it).
• Steel type – mild steel attracts best. Alloy admixtures reduce magnetic permeability and holding force.
• Surface structure – the smoother and more polished the plate, the better the adhesion and stronger the hold. Roughness creates an air distance.
• Operating temperature – NdFeB sinters have a sensitivity to temperature. When it is hot they are weaker, and at low temperatures gain strength (up to a certain limit).

* Holding force was measured on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, however under parallel forces the load capacity is reduced by as much as fivefold. Additionally, even a small distance {between} the magnet and the plate decreases the lifting capacity.