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

Strengths as well as weaknesses of neodymium magnets.

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

• They do not lose strength, even after around 10 years – the drop in strength is only ~1% (according to tests),
• Magnets very well protect themselves against demagnetization caused by external fields,
• A magnet with a metallic nickel surface has an effective appearance,
• Neodymium magnets create maximum magnetic induction on a their surface, which increases force concentration,
• 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...
• Due to the option of flexible molding and adaptation to unique requirements, NdFeB magnets can be manufactured in a wide range of geometric configurations, which makes them more universal,
• Significant place in advanced technology sectors – they find application in computer drives, electric drive systems, diagnostic systems, as well as other advanced devices.
• Compactness – despite small sizes they provide effective action, making them ideal for precision applications

Cons of neodymium magnets: weaknesses and usage proposals

• They are fragile upon too strong impacts. To avoid cracks, it is worth protecting magnets in special housings. Such protection not only protects the magnet but also increases its resistance to damage
• We warn that neodymium magnets can lose their power at high temperatures. To prevent this, we recommend our specialized [AH] magnets, which work effectively even at 230°C.
• When exposed to humidity, magnets usually rust. For applications outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which secure oxidation and corrosion.
• Limited possibility of making nuts in the magnet and complicated shapes - recommended is cover - mounting mechanism.
• Possible danger resulting from small fragments of magnets are risky, when accidentally swallowed, which gains importance in the context of child health protection. Additionally, small components of these products are able to be problematic in diagnostics medical in case of swallowing.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Maximum lifting capacity of the magnet – what affects it?

The load parameter shown represents the maximum value, obtained under optimal environment, meaning:

• using a base made of high-permeability steel, acting as a ideal flux conductor
• with a thickness minimum 10 mm
• with an ideally smooth contact surface
• without any insulating layer between the magnet and steel
• during detachment in a direction perpendicular to the mounting surface
• at ambient temperature room level

Lifting capacity in practice – influencing factors

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

• Gap between surfaces – even a fraction of a millimeter of separation (caused e.g. by veneer or unevenness) drastically reduces the pulling force, often by half at just 0.5 mm.
• Force direction – catalog parameter refers to detachment vertically. When attempting to slide, the magnet holds much less (typically approx. 20-30% of maximum force).
• Metal thickness – the thinner the sheet, the weaker the hold. Magnetic flux passes through the material instead of generating force.
• Material composition – not every steel reacts the same. High carbon content weaken the interaction with the magnet.
• Surface finish – ideal contact is possible only on polished steel. Rough texture reduce the real contact area, weakening the magnet.
• Operating temperature – neodymium magnets have a sensitivity to temperature. At higher temperatures they lose power, and in frost they can be stronger (up to a certain limit).

* Lifting capacity was measured with the use of a steel plate with a smooth surface of optimal thickness (min. 20 mm), under vertically applied force, in contrast under shearing force the load capacity is reduced by as much as 5 times. Additionally, even a small distance {between} the magnet and the plate decreases the holding force.