SMZR 25x150 / N52 - magnetic separator with handle

Advantages and disadvantages of NdFeB magnets.

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

• They have stable power, and over nearly ten years their attraction force decreases symbolically – ~1% (according to theory),
• They are resistant to demagnetization induced by external field influence,
• By applying a smooth layer of silver, the element acquires an nice look,
• Neodymium magnets ensure 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...
• Considering the potential of flexible molding and adaptation to custom needs, neodymium magnets can be created in a broad palette of forms and dimensions, which expands the range of possible applications,
• Versatile presence in modern technologies – they find application in magnetic memories, electric drive systems, medical equipment, also complex engineering applications.
• Relatively small size with high pulling force – neodymium magnets offer impressive pulling force in tiny dimensions, which enables their usage in compact constructions

Drawbacks and weaknesses of neodymium magnets: tips and applications.

• At strong impacts they can crack, therefore we recommend placing them in steel cases. A metal housing provides additional protection against damage and increases the magnet's durability.
• We warn that neodymium magnets can reduce their strength 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 as well as corrosion.
• We suggest cover - magnetic mechanism, due to difficulties in producing nuts inside the magnet and complicated forms.
• Possible danger resulting from small fragments of magnets can be dangerous, if swallowed, which becomes key in the context of child health protection. It is also worth noting that small components of these magnets can complicate diagnosis medical when they are in the body.
• High unit price – neodymium magnets are more expensive than other types of magnets (e.g. ferrite), which increases costs of application in large quantities

Detachment force of the magnet in optimal conditions – what contributes to it?

Information about lifting capacity is the result of a measurement for the most favorable conditions, including:

• with the application of a sheet made of special test steel, ensuring maximum field concentration
• possessing a massiveness of minimum 10 mm to ensure full flux closure
• with a surface perfectly flat
• without any air gap between the magnet and steel
• for force applied at a right angle (pull-off, not shear)
• at ambient temperature approx. 20 degrees Celsius

Determinants of practical lifting force of a magnet

Please note that the working load will differ depending on elements below, starting with the most relevant:

• Distance – the presence of any layer (paint, dirt, gap) acts as an insulator, which lowers capacity rapidly (even by 50% at 0.5 mm).
• Direction of force – highest force is obtained only during pulling at a 90° angle. The resistance to sliding of the magnet along the surface is standardly several times lower (approx. 1/5 of the lifting capacity).
• Wall thickness – the thinner the sheet, the weaker the hold. Magnetic flux passes through the material instead of converting into lifting capacity.
• Steel grade – ideal substrate is pure iron steel. Stainless steels may generate lower lifting capacity.
• Surface quality – the smoother and more polished the surface, the better the adhesion and stronger the hold. Unevenness acts like micro-gaps.
• Operating temperature – NdFeB sinters have a negative temperature coefficient. When it is hot they lose power, and in frost gain strength (up to a certain limit).

* Lifting capacity was measured using a steel plate with a smooth surface of optimal thickness (min. 20 mm), under perpendicular detachment force, in contrast under attempts to slide the magnet the load capacity is reduced by as much as 5 times. In addition, even a minimal clearance {between} the magnet and the plate reduces the holding force.