SMZR 25x225 / N52 - magnetic separator with handle

Pros as well as cons of neodymium magnets.

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

• They virtually do not lose strength, because even after 10 years the performance loss is only ~1% (in laboratory conditions),
• Magnets perfectly protect themselves against loss of magnetization caused by foreign field sources,
• Thanks to the shimmering finish, the layer of nickel, gold, or silver gives an professional appearance,
• They show high magnetic induction at the operating surface, making them more effective,
• Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and can work (depending on the shape) even at a temperature of 230°C or more...
• Due to the ability of accurate forming and customization to custom needs, NdFeB magnets can be produced in a wide range of shapes and sizes, which amplifies use scope,
• Fundamental importance in modern technologies – they are commonly used in mass storage devices, motor assemblies, diagnostic systems, and technologically advanced constructions.
• Compactness – despite small sizes they provide effective action, making them ideal for precision applications

Characteristics of disadvantages of neodymium magnets: weaknesses and usage proposals

• Susceptibility to cracking is one of their disadvantages. Upon intense impact they can fracture. We advise keeping them in a strong case, which not only protects them against impacts but also raises their durability
• Neodymium magnets decrease their power under the influence of heating. As soon as 80°C is exceeded, many of them start losing their power. Therefore, we recommend our special magnets marked [AH], which maintain durability even at temperatures up to 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 and corrosion.
• We recommend a housing - magnetic mechanism, due to difficulties in creating threads inside the magnet and complicated shapes.
• Potential hazard related to microscopic parts of magnets can be dangerous, when accidentally swallowed, which becomes key in the context of child safety. It is also worth noting that tiny parts of these devices are able to complicate diagnosis medical in case of swallowing.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Maximum magnetic pulling force – what affects it?

The load parameter shown concerns the maximum value, obtained under optimal environment, namely:

• with the use of a sheet made of special test steel, guaranteeing maximum field concentration
• possessing a massiveness of at least 10 mm to ensure full flux closure
• with a surface cleaned and smooth
• without any clearance between the magnet and steel
• under axial force direction (90-degree angle)
• at conditions approx. 20°C

Lifting capacity in practice – influencing factors

Real force impacted by specific conditions, such as (from priority):

• Distance (between the magnet and the plate), as even a tiny clearance (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 – remember that the magnet has greatest strength perpendicularly. Under sliding down, the capacity drops significantly, often to levels of 20-30% of the maximum value.
• Substrate thickness – to utilize 100% power, the steel must be sufficiently thick. Paper-thin metal limits the lifting capacity (the magnet "punches through" it).
• Plate material – mild steel gives the best results. Alloy steels decrease magnetic permeability and lifting capacity.
• Base smoothness – the smoother and more polished the plate, the larger the contact zone and higher the lifting capacity. Roughness acts like micro-gaps.
• Temperature influence – high temperature reduces magnetic field. Too high temperature can permanently demagnetize the magnet.

* Lifting capacity testing was performed on a smooth plate of optimal thickness, under perpendicular forces, however under attempts to slide the magnet the load capacity is reduced by as much as 75%. Additionally, even a slight gap {between} the magnet’s surface and the plate lowers the load capacity.