SM 32x425 [2xM8] / N42 - magnetic separator

Pros and cons of NdFeB magnets.

In addition to their pulling strength, neodymium magnets provide the following advantages:

• They have constant strength, and over around ten years their attraction force decreases symbolically – ~1% (in testing),
• They retain their magnetic properties even under external field action,
• By using a decorative layer of nickel, the element presents an proper look,
• Magnetic induction on the surface of the magnet remains impressive,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their shape) at temperatures up to 230°C and above...
• Possibility of detailed shaping as well as adapting to complex applications,
• Fundamental importance in high-tech industry – they serve a role in magnetic memories, electric motors, advanced medical instruments, also complex engineering applications.
• Thanks to efficiency per cm³, small magnets offer high operating force, with minimal size,

Characteristics of disadvantages of neodymium magnets and ways of using them

• They are fragile upon too strong impacts. To avoid cracks, it is worth securing magnets in special housings. Such protection not only shields the magnet but also increases its resistance to damage
• Neodymium magnets decrease their power under the influence of heating. As soon as 80°C is exceeded, many of them start losing their force. Therefore, we recommend our special magnets marked [AH], which maintain durability even at temperatures up to 230°C
• Magnets exposed to a humid environment can rust. Therefore when using outdoors, we suggest using waterproof magnets made of rubber, plastic or other material resistant to moisture
• Limited ability of creating threads in the magnet and complicated forms - recommended is a housing - mounting mechanism.
• Health risk related to microscopic parts of magnets are risky, if swallowed, which becomes key in the context of child health protection. It is also worth noting that small components of these products can complicate diagnosis medical in case of swallowing.
• Due to neodymium price, their price is relatively high,

Optimal lifting capacity of a neodymium magnet – what affects it?

Breakaway force was determined for ideal contact conditions, including:

• using a plate made of low-carbon steel, functioning as a circuit closing element
• with a thickness of at least 10 mm
• with a plane cleaned and smooth
• with zero gap (no impurities)
• during pulling in a direction vertical to the plane
• at ambient temperature approx. 20 degrees Celsius

Lifting capacity in real conditions – factors

Effective lifting capacity is affected by working environment parameters, mainly (from most important):

• Gap between magnet and steel – even a fraction of a millimeter of separation (caused e.g. by varnish or dirt) diminishes the pulling force, often by half at just 0.5 mm.
• Loading method – catalog parameter refers to pulling vertically. When applying parallel force, the magnet exhibits significantly lower power (often approx. 20-30% of maximum force).
• Element thickness – to utilize 100% power, the steel must be adequately massive. Thin sheet restricts the attraction force (the magnet "punches through" it).
• Steel grade – ideal substrate is pure iron steel. Hardened steels may have worse magnetic properties.
• Plate texture – ground elements ensure maximum contact, which improves force. Rough surfaces reduce efficiency.
• Temperature influence – high temperature weakens magnetic field. Exceeding the limit temperature can permanently demagnetize the magnet.

* Holding force was tested on the plate surface of 20 mm thickness, when the force acted perpendicularly, however under attempts to slide the magnet the holding force is lower. Additionally, even a slight gap {between} the magnet’s surface and the plate lowers the lifting capacity.