SM 32x325 [2xM8] / N52 - magnetic separator

Strengths and weaknesses of NdFeB magnets.

In addition to their magnetic capacity, neodymium magnets provide the following advantages:

• They virtually do not lose power, because even after ten years the performance loss is only ~1% (in laboratory conditions),
• They possess excellent resistance to magnetic field loss as a result of external magnetic sources,
• A magnet with a smooth silver surface is more attractive,
• They show high magnetic induction at the operating surface, which improves attraction properties,
• Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the form) even at high temperatures reaching 230°C or more...
• Possibility of detailed forming as well as modifying to complex requirements,
• Significant place in future technologies – they are utilized in mass storage devices, motor assemblies, precision medical tools, as well as other advanced devices.
• Relatively small size with high pulling force – neodymium magnets offer high power in compact dimensions, which makes them useful in compact constructions

Cons of neodymium magnets: weaknesses and usage proposals

• At strong impacts they can crack, therefore we advise placing them in strong housings. A metal housing provides additional protection against damage and increases the magnet's durability.
• When exposed to high temperature, neodymium magnets experience a drop in force. Often, when the temperature exceeds 80°C, their strength decreases (depending on the size and shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
• Magnets exposed to a humid environment can rust. Therefore while using outdoors, we advise using waterproof magnets made of rubber, plastic or other material protecting against moisture
• Due to limitations in producing nuts and complicated forms in magnets, we propose using cover - magnetic mechanism.
• Health risk to health – tiny shards of magnets are risky, when accidentally swallowed, which becomes key in the aspect of protecting the youngest. It is also worth noting that small elements of these magnets can disrupt the diagnostic process medical after entering the body.
• Due to neodymium price, their price exceeds standard values,

Maximum magnetic pulling force – what affects it?

Magnet power was determined for the most favorable conditions, including:

• on a block made of mild steel, perfectly concentrating the magnetic field
• with a cross-section no less than 10 mm
• characterized by even structure
• under conditions of ideal adhesion (surface-to-surface)
• under perpendicular force vector (90-degree angle)
• at temperature room level

Determinants of practical lifting force of a magnet

Bear in mind that the magnet holding may be lower depending on the following factors, starting with the most relevant:

• Clearance – the presence of foreign body (paint, tape, air) interrupts the magnetic circuit, which lowers capacity rapidly (even by 50% at 0.5 mm).
• Pull-off angle – note that the magnet has greatest strength perpendicularly. Under sliding down, the capacity drops drastically, often to levels of 20-30% of the maximum value.
• Substrate thickness – for full efficiency, the steel must be adequately massive. Thin sheet restricts the attraction force (the magnet "punches through" it).
• Chemical composition of the base – mild steel attracts best. Alloy steels reduce magnetic properties and lifting capacity.
• Base smoothness – the more even the plate, the better the adhesion and stronger the hold. Roughness acts like micro-gaps.
• Thermal factor – high temperature weakens magnetic field. Too high temperature can permanently damage the magnet.

* Holding force was measured on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, in contrast under attempts to slide the magnet the holding force is lower. In addition, even a small distance {between} the magnet and the plate reduces the holding force.