SM 18x300 [2xM5] / N42 - magnetic separator

Advantages and disadvantages of neodymium magnets.

In addition to their long-term stability, neodymium magnets provide the following advantages:

• They retain magnetic properties for almost 10 years – the drop is just ~1% (in theory),
• They show high resistance to demagnetization induced by external field influence,
• Thanks to the smooth finish, the coating of nickel, gold, or silver-plated gives an modern appearance,
• Magnetic induction on the top side of the magnet is strong,
• Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the form) even at high temperatures reaching 230°C or more...
• Thanks to freedom in shaping and the capacity to adapt to client solutions,
• Fundamental importance in high-tech industry – they find application in mass storage devices, electric drive systems, diagnostic systems, also technologically advanced constructions.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

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

• To avoid cracks upon strong impacts, we suggest using special steel holders. Such a solution secures the magnet and simultaneously increases its durability.
• We warn that neodymium magnets can reduce their strength at high temperatures. To prevent this, we suggest our specialized [AH] magnets, which work effectively even at 230°C.
• Due to the susceptibility of magnets to corrosion in a humid environment, we suggest using waterproof magnets made of rubber, plastic or other material stable to moisture, in case of application outdoors
• We recommend a housing - magnetic mount, due to difficulties in creating threads inside the magnet and complicated shapes.
• Potential hazard resulting from small fragments of magnets can be dangerous, in case of ingestion, which becomes key in the aspect of protecting the youngest. Furthermore, tiny parts of these devices can be problematic in diagnostics medical after entering the body.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Maximum lifting capacity of the magnet – what it depends on?

The declared magnet strength refers to the peak performance, recorded under ideal test conditions, namely:

• on a block made of mild steel, optimally conducting the magnetic flux
• whose transverse dimension is min. 10 mm
• with an ideally smooth contact surface
• with total lack of distance (no paint)
• for force acting at a right angle (pull-off, not shear)
• in temp. approx. 20°C

What influences lifting capacity in practice

Effective lifting capacity is influenced by specific conditions, such as (from priority):

• Distance (betwixt the magnet and the metal), as even a tiny distance (e.g. 0.5 mm) results in a drastic drop in lifting capacity by up to 50% (this also applies to varnish, corrosion or debris).
• Angle of force application – highest force is available only during perpendicular pulling. The force required to slide of the magnet along the plate is usually several times smaller (approx. 1/5 of the lifting capacity).
• Steel thickness – insufficiently thick plate does not close the flux, causing part of the power to be escaped into the air.
• Steel grade – the best choice is pure iron steel. Hardened steels may generate lower lifting capacity.
• Base smoothness – the smoother and more polished the surface, the better the adhesion and higher the lifting capacity. Roughness creates an air distance.
• Thermal conditions – neodymium magnets have a sensitivity to temperature. At higher temperatures they are weaker, and at low temperatures they can be stronger (up to a certain limit).

* Holding force was tested on the plate surface of 20 mm thickness, when the force acted perpendicularly, however under parallel forces the holding force is lower. In addition, even a minimal clearance {between} the magnet and the plate decreases the holding force.