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

Advantages as well as disadvantages of neodymium magnets.

Apart from their strong power, neodymium magnets have these key benefits:

• They have stable power, and over around ten years their performance decreases symbolically – ~1% (in testing),
• They feature excellent resistance to magnetic field loss as a result of opposing magnetic fields,
• Thanks to the glossy finish, the plating of Ni-Cu-Ni, gold-plated, or silver gives an clean appearance,
• They are known for high magnetic induction at the operating surface, which increases their power,
• Through (adequate) combination of ingredients, they can achieve high thermal strength, enabling operation at temperatures approaching 230°C and above...
• Thanks to freedom in shaping and the ability to customize to unusual requirements,
• Significant place in modern technologies – they serve a role in data components, drive modules, precision medical tools, as well as industrial machines.
• Relatively small size with high pulling force – neodymium magnets offer high power in tiny dimensions, which enables their usage in compact constructions

Drawbacks and weaknesses of neodymium magnets and ways of using them

• To avoid cracks under impact, we recommend using special steel housings. Such a solution secures the magnet and simultaneously increases its durability.
• NdFeB magnets lose force when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of power (a factor is the shape as well as 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
• Due to the susceptibility of magnets to corrosion in a humid environment, we suggest using waterproof magnets made of rubber, plastic or other material stable to moisture, in case of application outdoors
• We recommend a housing - magnetic mechanism, due to difficulties in producing nuts inside the magnet and complex forms.
• Health risk related to microscopic parts of magnets pose a threat, in case of ingestion, which gains importance in the context of child health protection. Furthermore, tiny parts of these products are able to complicate diagnosis medical after entering the body.
• Due to neodymium price, their price exceeds standard values,

Maximum holding power of the magnet – what contributes to it?

Breakaway force was defined for ideal contact conditions, taking into account:

• using a plate made of high-permeability steel, functioning as a ideal flux conductor
• possessing a massiveness of minimum 10 mm to avoid saturation
• characterized by smoothness
• under conditions of gap-free contact (metal-to-metal)
• under axial application of breakaway force (90-degree angle)
• at room temperature

Key elements affecting lifting force

In practice, the actual holding force is determined by many variables, ranked from the most important:

• Gap (between the magnet and the metal), because even a tiny clearance (e.g. 0.5 mm) can cause a drastic drop in force by up to 50% (this also applies to paint, corrosion or debris).
• Loading method – catalog parameter refers to pulling vertically. When attempting to slide, the magnet holds significantly lower power (typically approx. 20-30% of nominal force).
• Metal thickness – thin material does not allow full use of the magnet. Part of the magnetic field passes through the material instead of converting into lifting capacity.
• Steel type – low-carbon steel attracts best. Higher carbon content decrease magnetic permeability and holding force.
• Base smoothness – the smoother and more polished the plate, the better the adhesion and stronger the hold. Roughness acts like micro-gaps.
• Thermal factor – hot environment reduces pulling force. Exceeding the limit temperature can permanently damage the magnet.

* Lifting capacity testing was carried out on a smooth plate of optimal thickness, under perpendicular forces, whereas under attempts to slide the magnet the load capacity is reduced by as much as 75%. Moreover, even a small distance {between} the magnet’s surface and the plate reduces the lifting capacity.