SM 32x500 [2xM8] / N42 - magnetic separator

Pros as well as cons of rare earth magnets.

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

• They have stable power, and over nearly ten years their attraction force decreases symbolically – ~1% (according to theory),
• They are resistant to demagnetization induced by external disturbances,
• The use of an shiny layer of noble metals (nickel, gold, silver) causes the element to present itself better,
• Neodymium magnets ensure maximum magnetic induction on a contact point, which ensures high operational effectiveness,
• Through (adequate) combination of ingredients, they can achieve high thermal strength, allowing for functioning at temperatures reaching 230°C and above...
• Possibility of custom forming as well as adjusting to precise needs,
• Wide application in high-tech industry – they are commonly used in HDD drives, electric motors, medical equipment, also technologically advanced constructions.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Disadvantages of neodymium magnets:

• They are fragile upon heavy impacts. To avoid cracks, it is worth protecting magnets in special housings. Such protection not only protects the magnet but also increases its resistance to damage
• Neodymium magnets decrease their force 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 stability even at temperatures up to 230°C
• Magnets exposed to a humid environment can rust. Therefore while using outdoors, we suggest using waterproof magnets made of rubber, plastic or other material protecting against moisture
• Due to limitations in producing nuts and complicated shapes in magnets, we propose using cover - magnetic mount.
• Potential hazard to health – tiny shards of magnets can be dangerous, in case of ingestion, which is particularly important in the context of child safety. Additionally, small components of these products are able to be problematic in diagnostics medical after entering the body.
• High unit price – neodymium magnets cost more than other types of magnets (e.g. ferrite), which hinders application in large quantities

Detachment force of the magnet in optimal conditions – what affects it?

Breakaway force is the result of a measurement for the most favorable conditions, taking into account:

• on a block made of mild steel, optimally conducting the magnetic field
• with a cross-section minimum 10 mm
• with a plane free of scratches
• without the slightest insulating layer between the magnet and steel
• during pulling in a direction vertical to the plane
• at conditions approx. 20°C

What influences lifting capacity in practice

It is worth knowing that the magnet holding will differ depending on the following factors, in order of importance:

• Gap between surfaces – even a fraction of a millimeter of distance (caused e.g. by veneer or dirt) significantly weakens the pulling force, often by half at just 0.5 mm.
• Force direction – declared lifting capacity refers to pulling vertically. When applying parallel force, the magnet holds significantly lower power (typically approx. 20-30% of nominal force).
• Metal thickness – the thinner the sheet, the weaker the hold. Magnetic flux passes through the material instead of converting into lifting capacity.
• Metal type – different alloys reacts the same. Alloy additives weaken the attraction effect.
• Plate texture – ground elements guarantee perfect abutment, which improves force. Uneven metal reduce efficiency.
• Thermal factor – high temperature reduces pulling force. Too high temperature can permanently damage the magnet.

* Lifting capacity was assessed using a polished steel plate of optimal thickness (min. 20 mm), under vertically applied force, in contrast under shearing force the lifting capacity is smaller. Additionally, even a slight gap {between} the magnet and the plate reduces the load capacity.