SM 32x150 [2xM8] / N42 - magnetic separator

Pros and cons of rare earth magnets.

Apart from their consistent magnetic energy, neodymium magnets have these key benefits:

• They virtually do not lose power, because even after 10 years the performance loss is only ~1% (according to literature),
• They have excellent resistance to magnetic field loss as a result of external magnetic sources,
• By using a reflective layer of silver, the element presents an modern look,
• The surface of neodymium magnets generates a strong magnetic field – this is a key feature,
• Through (appropriate) combination of ingredients, they can achieve high thermal resistance, enabling functioning at temperatures reaching 230°C and above...
• Thanks to versatility in designing and the ability to customize to individual projects,
• Huge importance in modern industrial fields – they are used in magnetic memories, electric motors, advanced medical instruments, also industrial machines.
• Thanks to concentrated force, small magnets offer high operating force, with minimal size,

Characteristics of disadvantages of neodymium magnets: application proposals

• They are prone to damage upon too strong impacts. To avoid cracks, it is worth securing magnets using a steel holder. Such protection not only protects the magnet but also improves its resistance to damage
• Neodymium magnets decrease their strength under the influence of heating. As soon as 80°C is exceeded, many of them start losing their force. Therefore, we recommend our special magnets marked [AH], which maintain durability even at temperatures up to 230°C
• When exposed to humidity, magnets start to rust. For applications outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which secure oxidation as well as corrosion.
• Limited ability of creating nuts in the magnet and complicated shapes - preferred is cover - magnet mounting.
• Potential hazard to health – tiny shards of magnets pose a threat, if swallowed, which is particularly important in the context of child health protection. Furthermore, tiny parts of these magnets can complicate diagnosis medical after entering the body.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Optimal lifting capacity of a neodymium magnet – what it depends on?

The lifting capacity listed is a measurement result executed under specific, ideal conditions:

• on a plate made of mild steel, effectively closing the magnetic field
• possessing a massiveness of min. 10 mm to avoid saturation
• characterized by lack of roughness
• without the slightest clearance between the magnet and steel
• during detachment in a direction vertical to the mounting surface
• in neutral thermal conditions

What influences lifting capacity in practice

It is worth knowing that the application force may be lower subject to the following factors, in order of importance:

• Clearance – existence of any layer (paint, tape, air) acts as an insulator, which reduces power rapidly (even by 50% at 0.5 mm).
• Load vector – highest force is available only during pulling at a 90° angle. The shear force of the magnet along the surface is typically several times lower (approx. 1/5 of the lifting capacity).
• Wall thickness – the thinner the sheet, the weaker the hold. Magnetic flux penetrates through instead of generating force.
• Material composition – not every steel reacts the same. High carbon content weaken the interaction with the magnet.
• Surface finish – full contact is obtained only on smooth steel. Any scratches and bumps create air cushions, weakening the magnet.
• Operating temperature – neodymium magnets have a negative temperature coefficient. When it is hot they are weaker, and in frost gain strength (up to a certain limit).

* Holding force was tested on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, in contrast under attempts to slide the magnet the lifting capacity is smaller. In addition, even a minimal clearance {between} the magnet’s surface and the plate lowers the load capacity.