SM 32x150 [2xM8] / N42 - magnetic separator

Strengths as well as weaknesses of neodymium magnets.

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

• Their magnetic field is durable, and after around 10 years it decreases only by ~1% (theoretically),
• They have excellent resistance to weakening of magnetic properties as a result of external magnetic sources,
• A magnet with a smooth gold surface has better aesthetics,
• They feature high magnetic induction at the operating surface, which increases their power,
• Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and can function (depending on the shape) even at a temperature of 230°C or more...
• Possibility of accurate shaping and optimizing to individual applications,
• Versatile presence in modern technologies – they are commonly used in data components, brushless drives, medical devices, as well as complex engineering applications.
• Compactness – despite small sizes they provide effective action, making them ideal for precision applications

Disadvantages of neodymium magnets:

• They are prone to damage upon too strong impacts. To avoid cracks, it is worth securing magnets in a protective case. Such protection not only shields the magnet but also increases its resistance to damage
• Neodymium magnets lose 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 when using outdoors, we advise using water-impermeable magnets made of rubber, plastic or other material protecting against moisture
• Limited possibility of producing nuts in the magnet and complicated shapes - preferred is casing - mounting mechanism.
• Potential hazard related to microscopic parts of magnets are risky, in case of ingestion, which becomes key in the aspect of protecting the youngest. Furthermore, small components of these devices can disrupt the diagnostic process medical in case of swallowing.
• Due to complex production process, their price is relatively high,

Maximum magnetic pulling force – what it depends on?

The force parameter is a result of laboratory testing conducted under the following configuration:

• with the contact of a sheet made of low-carbon steel, guaranteeing maximum field concentration
• possessing a thickness of minimum 10 mm to ensure full flux closure
• with a surface perfectly flat
• without the slightest air gap between the magnet and steel
• during detachment in a direction perpendicular to the mounting surface
• at standard ambient temperature

Practical lifting capacity: influencing factors

It is worth knowing that the working load will differ influenced by the following factors, in order of importance:

• Air gap (between the magnet and the plate), because even a tiny clearance (e.g. 0.5 mm) results in a reduction in lifting capacity by up to 50% (this also applies to paint, corrosion or dirt).
• Pull-off angle – note that the magnet holds strongest perpendicularly. Under shear forces, the holding force drops drastically, often to levels of 20-30% of the nominal value.
• Base massiveness – too thin plate causes magnetic saturation, causing part of the power to be escaped to the other side.
• Material composition – not every steel attracts identically. High carbon content worsen the interaction with the magnet.
• Surface condition – smooth surfaces ensure maximum contact, which improves force. Uneven metal weaken the grip.
• Operating temperature – NdFeB sinters have a sensitivity to temperature. When it is hot they are weaker, and at low temperatures gain strength (up to a certain limit).

* Lifting capacity was assessed by applying a smooth steel plate of suitable thickness (min. 20 mm), under perpendicular pulling force, in contrast under parallel forces the load capacity is reduced by as much as 5 times. Moreover, even a small distance {between} the magnet’s surface and the plate reduces the holding force.