SM 32x425 [2xM8] / N52 - magnetic separator

Advantages as well as disadvantages of NdFeB magnets.

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

• They retain attractive force for around 10 years – the loss is just ~1% (based on simulations),
• Neodymium magnets are characterized by exceptionally resistant to demagnetization caused by external magnetic fields,
• By covering with a decorative layer of gold, the element gains an professional look,
• They feature high magnetic induction at the operating surface, which increases their power,
• Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and can work (depending on the shape) even at a temperature of 230°C or more...
• Possibility of precise modeling as well as adjusting to atypical applications,
• Fundamental importance in future technologies – they serve a role in mass storage devices, electric drive systems, precision medical tools, also industrial machines.
• Thanks to their power density, small magnets offer high operating force, in miniature format,

Disadvantages of NdFeB magnets:

• Brittleness is one of their disadvantages. Upon intense impact they can break. We recommend keeping them in a strong case, which not only protects them against impacts but also increases their durability
• 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 when using outdoors, we recommend using water-impermeable magnets made of rubber, plastic or other material protecting against moisture
• Limited possibility of creating nuts in the magnet and complex forms - preferred is casing - magnetic holder.
• Potential hazard resulting from small fragments of magnets can be dangerous, when accidentally swallowed, which gains importance in the context of child health protection. Furthermore, small elements of these devices can complicate diagnosis medical after entering the body.
• Due to expensive raw materials, their price exceeds standard values,

Maximum magnetic pulling force – what affects it?

The declared magnet strength refers to the maximum value, recorded under laboratory conditions, namely:

• on a block made of structural steel, perfectly concentrating the magnetic field
• whose thickness is min. 10 mm
• with a surface cleaned and smooth
• with total lack of distance (without coatings)
• under perpendicular force direction (90-degree angle)
• at temperature room level

Practical lifting capacity: influencing factors

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

• Gap (betwixt the magnet and the metal), because even a tiny distance (e.g. 0.5 mm) can cause a reduction in lifting capacity by up to 50% (this also applies to paint, rust or debris).
• Force direction – note that the magnet has greatest strength perpendicularly. Under sliding down, the capacity drops drastically, often to levels of 20-30% of the nominal value.
• Plate thickness – insufficiently thick sheet does not close the flux, causing part of the power to be lost to the other side.
• Plate material – mild steel attracts best. Higher carbon content lower magnetic permeability and lifting capacity.
• Base smoothness – the smoother and more polished the surface, the better the adhesion and stronger the hold. Unevenness creates an air distance.
• Thermal conditions – NdFeB sinters have a negative temperature coefficient. When it is hot they lose power, and at low temperatures they can be stronger (up to a certain limit).

* Lifting capacity was assessed with the use of a polished steel plate of suitable thickness (min. 20 mm), under perpendicular detachment force, whereas under attempts to slide the magnet the holding force is lower. In addition, even a slight gap {between} the magnet’s surface and the plate reduces the holding force.