SM 25x200 [2xM8] / N52 - magnetic separator

Pros and cons of NdFeB magnets.

Besides their immense field intensity, neodymium magnets offer the following advantages:

• They do not lose magnetism, even after nearly 10 years – the reduction in strength is only ~1% (based on measurements),
• They are noted for resistance to demagnetization induced by external magnetic fields,
• In other words, due to the metallic layer of nickel, the element becomes visually attractive,
• They show high magnetic induction at the operating surface, which affects their effectiveness,
• Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the shape) even at high temperatures reaching 230°C or more...
• Thanks to the possibility of free molding and customization to custom needs, neodymium magnets can be modeled in a variety of forms and dimensions, which expands the range of possible applications,
• Wide application in high-tech industry – they are used in magnetic memories, electromotive mechanisms, diagnostic systems, and other advanced devices.
• Thanks to efficiency per cm³, small magnets offer high operating force, with minimal size,

Disadvantages of NdFeB magnets:

• Susceptibility to cracking is one of their disadvantages. Upon strong impact they can fracture. We advise keeping them in a special holder, which not only secures them against impacts but also increases their durability
• NdFeB magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of strength (a factor is the shape as well as dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are very resistant to heat
• Magnets exposed to a humid environment can corrode. Therefore while using outdoors, we advise using water-impermeable magnets made of rubber, plastic or other material resistant to moisture
• Due to limitations in producing threads and complicated forms in magnets, we recommend using cover - magnetic mechanism.
• Potential hazard to health – tiny shards of magnets are risky, in case of ingestion, which becomes key in the context of child safety. It is also worth noting that tiny parts of these products are able to 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

Breakaway strength of the magnet in ideal conditions – what affects it?

The load parameter shown refers to the maximum value, recorded under laboratory conditions, meaning:

• with the contact of a sheet made of low-carbon steel, ensuring maximum field concentration
• possessing a thickness of at least 10 mm to avoid saturation
• with an ideally smooth contact surface
• with zero gap (without paint)
• for force acting at a right angle (pull-off, not shear)
• in neutral thermal conditions

Key elements affecting lifting force

It is worth knowing that the magnet holding will differ subject to the following factors, starting with the most relevant:

• Air gap (betwixt the magnet and the plate), as even a tiny clearance (e.g. 0.5 mm) results in a drastic drop in force by up to 50% (this also applies to varnish, corrosion or debris).
• Direction of force – maximum parameter is obtained only during perpendicular pulling. The shear force of the magnet along the plate is usually many times lower (approx. 1/5 of the lifting capacity).
• Substrate thickness – for full efficiency, the steel must be adequately massive. Paper-thin metal restricts the lifting capacity (the magnet "punches through" it).
• Material composition – different alloys reacts the same. Alloy additives worsen the interaction with the magnet.
• Surface condition – smooth surfaces guarantee perfect abutment, which increases force. Rough surfaces weaken the grip.
• Temperature influence – high temperature reduces magnetic field. Too high temperature can permanently demagnetize the magnet.

* Holding force was measured on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, whereas under shearing force the load capacity is reduced by as much as 75%. Additionally, even a small distance {between} the magnet’s surface and the plate lowers the lifting capacity.