SM 32x350 [2xM8] / N52 - magnetic separator

Advantages and disadvantages of NdFeB magnets.

Besides their durability, neodymium magnets are valued for these benefits:

• They have stable power, and over nearly ten years their attraction force decreases symbolically – ~1% (in testing),
• Magnets very well defend themselves against loss of magnetization caused by foreign field sources,
• Thanks to the smooth finish, the surface of Ni-Cu-Ni, gold-plated, or silver-plated gives an professional appearance,
• Magnetic induction on the working part of the magnet remains exceptional,
• 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 flexibility in designing and the ability to customize to specific needs,
• Huge importance in innovative solutions – they are utilized in mass storage devices, brushless drives, medical equipment, and other advanced devices.
• Relatively small size with high pulling force – neodymium magnets offer impressive pulling force in tiny dimensions, which allows their use in miniature devices

Disadvantages of neodymium magnets:

• They are fragile upon heavy impacts. To avoid cracks, it is worth securing magnets in a protective case. Such protection not only protects the magnet but also improves its resistance to damage
• We warn that neodymium magnets can reduce their power at high temperatures. To prevent this, we advise our specialized [AH] magnets, which work effectively even at 230°C.
• Due to the susceptibility of magnets to corrosion in a humid environment, we recommend using waterproof magnets made of rubber, plastic or other material resistant to moisture, when using outdoors
• Due to limitations in creating nuts and complex forms in magnets, we recommend using casing - magnetic holder.
• Potential hazard related to microscopic parts of magnets pose a threat, if swallowed, which gains importance in the context of child safety. Furthermore, small elements of these devices are able to be problematic in diagnostics medical in case of swallowing.
• High unit price – neodymium magnets are more expensive 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?

The lifting capacity listed is a theoretical maximum value executed under the following configuration:

• with the application of a sheet made of low-carbon steel, guaranteeing maximum field concentration
• possessing a massiveness of min. 10 mm to avoid saturation
• characterized by even structure
• without the slightest air gap between the magnet and steel
• under perpendicular force vector (90-degree angle)
• at temperature approx. 20 degrees Celsius

Magnet lifting force in use – key factors

It is worth knowing that the magnet holding will differ depending on elements below, starting with the most relevant:

• Distance (betwixt the magnet and the plate), since even a tiny clearance (e.g. 0.5 mm) leads to a drastic drop in force by up to 50% (this also applies to varnish, corrosion or debris).
• Angle of force application – highest force is available only during pulling at a 90° angle. The force required to slide of the magnet along the plate is standardly several times lower (approx. 1/5 of the lifting capacity).
• Element thickness – to utilize 100% power, the steel must be adequately massive. Paper-thin metal limits the attraction force (the magnet "punches through" it).
• Material type – the best choice is high-permeability steel. Stainless steels may generate lower lifting capacity.
• Surface quality – the more even the plate, the better the adhesion and stronger the hold. Unevenness acts like micro-gaps.
• Temperature influence – hot environment weakens magnetic field. Exceeding the limit temperature can permanently demagnetize the magnet.

* Lifting capacity testing was carried out on plates with a smooth surface of optimal thickness, under perpendicular forces, in contrast under attempts to slide the magnet the lifting capacity is smaller. Additionally, even a slight gap {between} the magnet and the plate reduces the holding force.