SM 18x200 [2xM5] / N42 - magnetic separator

Pros as well as cons of NdFeB magnets.

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

• They retain magnetic properties for almost 10 years – the drop is just ~1% (in theory),
• Neodymium magnets prove to be exceptionally resistant to loss of magnetic properties caused by external field sources,
• A magnet with a metallic silver surface looks better,
• Magnets are characterized by excellent 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 form) at temperatures up to 230°C and above...
• Thanks to versatility in shaping and the capacity to modify to client solutions,
• Wide application in future technologies – they serve a role in magnetic memories, drive modules, diagnostic systems, as well as complex engineering applications.
• Compactness – despite small sizes they provide effective action, making them ideal for precision applications

Disadvantages of neodymium magnets:

• They are fragile upon heavy impacts. To avoid cracks, it is worth securing magnets in special housings. Such protection not only shields the magnet but also increases its resistance to damage
• When exposed to high temperature, neodymium magnets suffer a drop in strength. Often, when the temperature exceeds 80°C, their strength decreases (depending on the size, as well as shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
• When exposed to humidity, magnets usually rust. To use them in conditions outside, it is recommended to use protective magnets, such as those in rubber or plastics, which prevent oxidation as well as corrosion.
• Due to limitations in producing threads and complicated forms in magnets, we recommend using cover - magnetic mount.
• Possible danger resulting from small fragments of magnets pose a threat, in case of ingestion, which becomes key in the aspect of protecting the youngest. Additionally, tiny parts of these devices are able to complicate diagnosis medical when they are in the body.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Optimal lifting capacity of a neodymium magnet – what affects it?

Holding force of 0 kg is a measurement result performed under standard conditions:

• on a block made of mild steel, optimally conducting the magnetic flux
• possessing a thickness of minimum 10 mm to ensure full flux closure
• with a plane cleaned and smooth
• under conditions of gap-free contact (metal-to-metal)
• during pulling in a direction perpendicular to the mounting surface
• at conditions approx. 20°C

Practical lifting capacity: influencing factors

During everyday use, the real power depends on several key aspects, listed from the most important:

• Distance (between the magnet and the plate), because even a tiny clearance (e.g. 0.5 mm) leads to a drastic drop in force by up to 50% (this also applies to varnish, corrosion or debris).
• Pull-off angle – remember that the magnet holds strongest perpendicularly. Under shear forces, the capacity drops drastically, often to levels of 20-30% of the nominal value.
• Substrate thickness – for full efficiency, the steel must be adequately massive. Thin sheet limits the lifting capacity (the magnet "punches through" it).
• Chemical composition of the base – mild steel gives the best results. Alloy admixtures reduce magnetic permeability and lifting capacity.
• Smoothness – full contact is obtained only on polished steel. Any scratches and bumps create air cushions, reducing force.
• Temperature influence – hot environment reduces magnetic field. Exceeding the limit temperature can permanently demagnetize the magnet.

* Holding force was measured on the plate surface of 20 mm thickness, when a perpendicular force was applied, however under attempts to slide the magnet the holding force is lower. In addition, even a minimal clearance {between} the magnet and the plate reduces the load capacity.