SM 18x175 [2xM5] / N42 - magnetic separator

Pros as well as cons of rare earth magnets.

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

• They have unchanged lifting capacity, and over around ten years their attraction force decreases symbolically – ~1% (in testing),
• They are extremely resistant to demagnetization induced by external disturbances,
• Thanks to the glossy finish, the coating of Ni-Cu-Ni, gold, or silver gives an clean appearance,
• Magnets have maximum magnetic induction on the active area,
• 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 accurate modeling and adjusting to individual applications,
• Versatile presence in future technologies – they are utilized in magnetic memories, motor assemblies, advanced medical instruments, as well as complex engineering applications.
• Compactness – despite small sizes they provide effective action, making them ideal for precision applications

Characteristics of disadvantages of neodymium magnets: weaknesses and usage proposals

• To avoid cracks upon strong impacts, we suggest using special steel holders. Such a solution protects the magnet and simultaneously improves its durability.
• We warn that neodymium magnets can lose their strength at high temperatures. To prevent this, we recommend our specialized [AH] magnets, which work effectively even at 230°C.
• When exposed to humidity, magnets start to rust. To use them in conditions outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which secure oxidation as well as corrosion.
• Limited possibility of creating threads in the magnet and complex shapes - recommended is cover - mounting mechanism.
• Potential hazard related to microscopic parts of magnets can be dangerous, if swallowed, which becomes key in the aspect of protecting the youngest. It is also worth noting that small elements of these products can be problematic in diagnostics medical in case of swallowing.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Maximum magnetic pulling force – what it depends on?

The specified lifting capacity refers to the peak performance, obtained under optimal environment, namely:

• on a plate made of structural steel, perfectly concentrating the magnetic field
• possessing a massiveness of min. 10 mm to avoid saturation
• characterized by lack of roughness
• under conditions of ideal adhesion (surface-to-surface)
• under vertical application of breakaway force (90-degree angle)
• in stable room temperature

Determinants of practical lifting force of a magnet

In real-world applications, the actual lifting capacity is determined by several key aspects, ranked from the most important:

• Gap (betwixt the magnet and the metal), because even a tiny distance (e.g. 0.5 mm) leads to a drastic drop in lifting capacity by up to 50% (this also applies to paint, corrosion or dirt).
• Force direction – note that the magnet holds strongest perpendicularly. Under sliding down, the capacity drops significantly, often to levels of 20-30% of the maximum value.
• Steel thickness – insufficiently thick steel does not accept the full field, causing part of the flux to be wasted into the air.
• Metal type – not every steel attracts identically. High carbon content worsen the interaction with the magnet.
• Surface finish – ideal contact is possible only on smooth steel. Any scratches and bumps reduce the real contact area, weakening the magnet.
• Temperature – heating the magnet results in weakening of induction. Check the thermal limit for a given model.

* Lifting capacity testing was conducted on a smooth plate of suitable thickness, under a perpendicular pulling force, however under parallel forces the load capacity is reduced by as much as 75%. In addition, even a slight gap {between} the magnet and the plate decreases the lifting capacity.