SMZR 25x225 / N52 - magnetic separator with handle

Pros as well as cons of NdFeB magnets.

Besides their tremendous magnetic power, neodymium magnets offer the following advantages:

• They do not lose power, even during approximately 10 years – the drop in strength is only ~1% (based on measurements),
• They show high resistance to demagnetization induced by external disturbances,
• In other words, due to the shiny layer of nickel, the element looks attractive,
• Neodymium magnets ensure maximum magnetic induction on a contact point, 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...
• Possibility of accurate modeling as well as optimizing to complex needs,
• Fundamental importance in modern technologies – they are utilized in hard drives, electric drive systems, medical devices, and technologically advanced constructions.
• Thanks to concentrated force, small magnets offer high operating force, with minimal size,

Drawbacks and weaknesses of neodymium magnets: application proposals

• They are prone to damage upon heavy impacts. To avoid cracks, it is worth securing magnets using a steel holder. Such protection not only shields the magnet but also improves its resistance to damage
• 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.
• They oxidize in a humid environment. For use outdoors we advise using waterproof magnets e.g. in rubber, plastic
• Limited ability of making threads in the magnet and complex forms - preferred is casing - mounting mechanism.
• Health risk related to microscopic parts of magnets can be dangerous, if swallowed, which gains importance in the context of child health protection. Furthermore, tiny parts of these products are able to complicate diagnosis medical in case of swallowing.
• Due to neodymium price, their price is higher than average,

Maximum lifting capacity of the magnet – what contributes to it?

Information about lifting capacity was determined for the most favorable conditions, assuming:

• on a base made of mild steel, perfectly concentrating the magnetic flux
• with a cross-section of at least 10 mm
• with a plane free of scratches
• without any clearance between the magnet and steel
• under perpendicular force vector (90-degree angle)
• in temp. approx. 20°C

Practical lifting capacity: influencing factors

Bear in mind that the working load may be lower subject to the following factors, starting with the most relevant:

• Distance – existence of any layer (rust, tape, gap) interrupts the magnetic circuit, which reduces power steeply (even by 50% at 0.5 mm).
• Loading method – declared lifting capacity refers to detachment vertically. When attempting to slide, the magnet exhibits much less (often approx. 20-30% of maximum force).
• Wall thickness – thin material does not allow full use of the magnet. Part of the magnetic field passes through the material instead of converting into lifting capacity.
• Chemical composition of the base – mild steel gives the best results. Higher carbon content lower magnetic permeability and holding force.
• Base smoothness – the smoother and more polished the surface, the larger the contact zone and higher the lifting capacity. Unevenness creates an air distance.
• Thermal environment – heating the magnet results in weakening of force. Check the thermal limit for a given model.

* Lifting capacity was assessed using a polished steel plate of suitable thickness (min. 20 mm), under vertically applied force, however under shearing force the lifting capacity is smaller. Moreover, even a small distance {between} the magnet’s surface and the plate lowers the holding force.