SM 32x225 [2xM8] / N42 - magnetic separator

Pros as well as cons of NdFeB magnets.

Besides their magnetic performance, neodymium magnets are valued for these benefits:

• They have unchanged lifting capacity, and over more than ten years their attraction force decreases symbolically – ~1% (in testing),
• Neodymium magnets prove to be remarkably resistant to demagnetization caused by external interference,
• A magnet with a metallic nickel surface has an effective appearance,
• The surface of neodymium magnets generates a strong magnetic field – this is one of their assets,
• Thanks to resistance to high temperature, they are able to function (depending on the form) even at temperatures up to 230°C and higher...
• Thanks to versatility in designing and the ability to modify to unusual requirements,
• Huge importance in advanced technology sectors – they serve a role in HDD drives, electromotive mechanisms, precision medical tools, also multitasking production systems.
• Relatively small size with high pulling force – neodymium magnets offer strong magnetic field in tiny dimensions, which enables their usage in compact constructions

What to avoid - cons of neodymium magnets: tips and applications.

• They are prone to damage upon too strong impacts. To avoid cracks, it is worth protecting magnets using a steel holder. Such protection not only protects 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
• When exposed to humidity, magnets usually rust. For applications outside, it is recommended to use protective magnets, such as those in rubber or plastics, which prevent oxidation as well as corrosion.
• We recommend a housing - magnetic mount, due to difficulties in producing threads inside the magnet and complicated forms.
• Health risk related to microscopic parts of magnets are risky, when accidentally swallowed, which gains importance in the context of child safety. Additionally, small components of these magnets can disrupt the diagnostic process medical in case of swallowing.
• With budget limitations the cost of neodymium magnets is a challenge,

Maximum lifting capacity of the magnet – what affects it?

The load parameter shown refers to the maximum value, recorded under ideal test conditions, meaning:

• with the contact of a yoke made of low-carbon steel, guaranteeing maximum field concentration
• whose thickness reaches at least 10 mm
• characterized by smoothness
• with zero gap (no coatings)
• under axial force vector (90-degree angle)
• at temperature approx. 20 degrees Celsius

Magnet lifting force in use – key factors

In practice, the actual holding force results from a number of factors, presented from crucial:

• Distance – existence of foreign body (rust, tape, air) acts as an insulator, which lowers power rapidly (even by 50% at 0.5 mm).
• Force direction – note that the magnet has greatest strength perpendicularly. Under sliding down, the capacity drops significantly, often to levels of 20-30% of the maximum value.
• Wall thickness – thin material does not allow full use of the magnet. Part of the magnetic field penetrates through instead of generating force.
• Plate material – low-carbon steel gives the best results. Higher carbon content decrease magnetic properties and lifting capacity.
• Surface condition – ground elements ensure maximum contact, which increases field saturation. Uneven metal reduce efficiency.
• Thermal environment – temperature increase causes a temporary drop of force. It is worth remembering the maximum operating temperature for a given model.

* Lifting capacity was measured using a steel plate with a smooth surface of suitable thickness (min. 20 mm), under perpendicular detachment force, in contrast under shearing force the lifting capacity is smaller. Additionally, even a minimal clearance {between} the magnet’s surface and the plate lowers the load capacity.