SM 25x200 [2xM8] / N52 - magnetic separator

Advantages as well as disadvantages of rare earth magnets.

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

• They virtually do not lose power, because even after ten years the performance loss is only ~1% (according to literature),
• Magnets very well protect themselves against demagnetization caused by ambient magnetic noise,
• By covering with a decorative layer of gold, the element has an elegant look,
• Magnetic induction on the working layer of the magnet turns out to be maximum,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their shape) at temperatures up to 230°C and above...
• Possibility of custom forming as well as adapting to complex requirements,
• Fundamental importance in innovative solutions – they are utilized in mass storage devices, drive modules, medical devices, and industrial machines.
• Thanks to their power density, small magnets offer high operating force, with minimal size,

Cons of neodymium magnets and ways of using them

• They are prone to damage upon too strong impacts. To avoid cracks, it is worth securing magnets in a protective case. Such protection not only protects the magnet but also improves its resistance to damage
• We warn that neodymium magnets can reduce their strength at high temperatures. To prevent this, we recommend our specialized [AH] magnets, which work effectively even at 230°C.
• Magnets exposed to a humid environment can corrode. Therefore while using outdoors, we suggest using water-impermeable magnets made of rubber, plastic or other material resistant to moisture
• We recommend a housing - magnetic mount, due to difficulties in producing nuts inside the magnet and complicated forms.
• Possible danger resulting from small fragments of magnets can be dangerous, in case of ingestion, which gains importance in the aspect of protecting the youngest. Additionally, small components of these magnets are able to disrupt the diagnostic process medical after entering the body.
• Due to neodymium price, their price exceeds standard values,

Maximum magnetic pulling force – what affects it?

The force parameter is a result of laboratory testing performed under specific, ideal conditions:

• on a block made of structural steel, optimally conducting the magnetic field
• with a cross-section of at least 10 mm
• with a plane free of scratches
• without the slightest air gap between the magnet and steel
• for force applied at a right angle (pull-off, not shear)
• at temperature approx. 20 degrees Celsius

Key elements affecting lifting force

In practice, the actual lifting capacity depends on a number of factors, listed from crucial:

• Distance (between the magnet and the metal), as even a microscopic clearance (e.g. 0.5 mm) leads to a reduction in lifting capacity by up to 50% (this also applies to paint, rust or dirt).
• Force direction – note that the magnet has greatest strength perpendicularly. Under sliding down, the holding force drops drastically, often to levels of 20-30% of the maximum value.
• Substrate thickness – for full efficiency, the steel must be adequately massive. Paper-thin metal limits the attraction force (the magnet "punches through" it).
• Plate material – mild steel gives the best results. Alloy admixtures decrease magnetic permeability and lifting capacity.
• Surface condition – smooth surfaces ensure maximum contact, which improves field saturation. Rough surfaces reduce efficiency.
• Operating temperature – neodymium magnets have a negative temperature coefficient. When it is hot they are weaker, and in frost they can be stronger (up to a certain limit).

* Lifting capacity testing was performed on a smooth plate of suitable thickness, under a perpendicular pulling force, however under attempts to slide the magnet the holding force is lower. Additionally, even a small distance {between} the magnet’s surface and the plate decreases the load capacity.