SM 25x125 [2xM8] / N52 - magnetic separator

Strengths as well as weaknesses of neodymium magnets.

Besides their high retention, neodymium magnets are valued for these benefits:

• They virtually do not lose strength, because even after 10 years the performance loss is only ~1% (based on calculations),
• They possess excellent resistance to weakening of magnetic properties when exposed to external magnetic sources,
• By applying a shiny layer of silver, the element presents an nice look,
• Magnets possess excellent magnetic induction on the outer side,
• Due to their durability and thermal resistance, neodymium magnets can operate (depending on the form) even at high temperatures reaching 230°C or more...
• Possibility of individual creating and modifying to precise applications,
• Huge importance in modern industrial fields – they are commonly used in data components, motor assemblies, advanced medical instruments, as well as complex engineering applications.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Cons of neodymium magnets and proposals for their use:

• Brittleness is one of their disadvantages. Upon strong impact they can fracture. We advise keeping them in a strong case, which not only secures them against impacts but also raises their 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.
• Magnets exposed to a humid environment can corrode. Therefore when using outdoors, we advise using water-impermeable magnets made of rubber, plastic or other material protecting against moisture
• Limited possibility of producing nuts in the magnet and complicated shapes - preferred is a housing - mounting mechanism.
• Potential hazard related to microscopic parts of magnets can be dangerous, when accidentally swallowed, which is particularly important in the context of child health protection. It is also worth noting that small components of these devices are able to disrupt the diagnostic process medical in case of swallowing.
• Due to neodymium price, their price exceeds standard values,

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

Magnet power was defined for optimal configuration, taking into account:

• on a plate made of mild steel, effectively closing the magnetic field
• possessing a massiveness of at least 10 mm to ensure full flux closure
• characterized by even structure
• without the slightest clearance between the magnet and steel
• during detachment in a direction vertical to the plane
• at ambient temperature room level

Determinants of practical lifting force of a magnet

Holding efficiency is influenced by working environment parameters, mainly (from most important):

• Distance (between the magnet and the metal), as even a microscopic distance (e.g. 0.5 mm) leads to a reduction in force by up to 50% (this also applies to varnish, rust or dirt).
• Pull-off angle – note that the magnet holds strongest perpendicularly. Under shear forces, the holding force drops significantly, often to levels of 20-30% of the maximum value.
• Base massiveness – too thin steel does not accept the full field, causing part of the power to be lost into the air.
• Steel grade – the best choice is pure iron steel. Cast iron may generate lower lifting capacity.
• Surface structure – the smoother and more polished the plate, the larger the contact zone and higher the lifting capacity. Roughness acts like micro-gaps.
• Temperature – heating the magnet results in weakening of force. It is worth remembering the thermal limit for a given model.

* Lifting capacity was measured using a smooth steel plate of suitable thickness (min. 20 mm), under vertically applied force, however under parallel forces the holding force is lower. Moreover, even a small distance {between} the magnet and the plate decreases the lifting capacity.