SMZR 32x150 / N52 - magnetic separator with handle

Pros and cons of rare earth magnets.

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

• They have stable power, and over around 10 years their performance decreases symbolically – ~1% (according to theory),
• They show high resistance to demagnetization induced by presence of other magnetic fields,
• Thanks to the shimmering finish, the surface of Ni-Cu-Ni, gold-plated, or silver gives an modern appearance,
• Magnetic induction on the working part of the magnet remains very high,
• 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...
• Considering the ability of free forming and customization to custom solutions, magnetic components can be modeled in a variety of forms and dimensions, which makes them more universal,
• Versatile presence in innovative solutions – they are utilized in HDD drives, electric motors, medical devices, and modern systems.
• Thanks to efficiency per cm³, small magnets offer high operating force, occupying minimum space,

Disadvantages of NdFeB magnets:

• They are prone to damage upon too strong impacts. To avoid cracks, it is worth protecting magnets in a protective case. Such protection not only shields the magnet but also improves its resistance to damage
• Neodymium magnets lose force when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of strength (a factor is the shape and dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are extremely resistant to heat
• 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 secure oxidation as well as corrosion.
• Limited possibility of making threads in the magnet and complex forms - recommended is casing - magnet mounting.
• Possible danger to health – tiny shards of magnets pose a threat, if swallowed, which gains importance in the context of child health protection. Furthermore, small components of these devices are able to disrupt the diagnostic process medical in case of swallowing.
• Due to complex production process, their price exceeds standard values,

Magnetic strength at its maximum – what contributes to it?

Information about lifting capacity was determined for optimal configuration, taking into account:

• using a plate made of high-permeability steel, functioning as a magnetic yoke
• with a thickness of at least 10 mm
• characterized by lack of roughness
• without any air gap between the magnet and steel
• during detachment in a direction vertical to the mounting surface
• in stable room temperature

Practical aspects of lifting capacity – factors

In real-world applications, the real power is determined by many variables, presented from most significant:

• Distance (between the magnet and the plate), since even a very small clearance (e.g. 0.5 mm) leads to a drastic drop in lifting capacity by up to 50% (this also applies to varnish, rust or debris).
• Force direction – note that the magnet has greatest strength perpendicularly. Under sliding down, the holding force drops significantly, often to levels of 20-30% of the nominal value.
• Wall thickness – the thinner the sheet, the weaker the hold. Part of the magnetic field penetrates through instead of generating force.
• Metal type – different alloys reacts the same. High carbon content weaken the interaction with the magnet.
• Surface structure – the smoother and more polished the surface, the larger the contact zone and higher the lifting capacity. Roughness creates an air distance.
• Operating temperature – NdFeB sinters have a sensitivity to temperature. When it is hot they are weaker, and at low temperatures gain strength (up to a certain limit).

* Holding force was tested on the plate surface of 20 mm thickness, when the force acted perpendicularly, whereas under attempts to slide the magnet the lifting capacity is smaller. Moreover, even a small distance {between} the magnet’s surface and the plate reduces the holding force.