UMP 75x24 [M8+M10] GW F 200 kg - search holder

Advantages and disadvantages of rare earth magnets.

In addition to their long-term stability, neodymium magnets provide the following advantages:

• They retain attractive force for nearly 10 years – the loss is just ~1% (according to analyses),
• They are resistant to demagnetization induced by presence of other magnetic fields,
• In other words, due to the smooth surface of nickel, the element gains visual value,
• Neodymium magnets generate maximum magnetic induction on a small surface, which allows for strong attraction,
• 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...
• Thanks to versatility in designing and the capacity to modify to unusual requirements,
• Significant place in future technologies – they serve a role in mass storage devices, brushless drives, precision medical tools, also modern systems.
• Thanks to their power density, small magnets offer high operating force, occupying minimum space,

Cons of neodymium magnets: weaknesses and usage proposals

• At strong impacts they can crack, therefore we recommend placing them in special holders. A metal housing provides additional protection against damage and increases the magnet's durability.
• Neodymium magnets lose 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
• They rust in a humid environment. For use outdoors we recommend using waterproof magnets e.g. in rubber, plastic
• We recommend cover - magnetic mount, due to difficulties in creating nuts inside the magnet and complicated forms.
• Potential hazard to health – tiny shards of magnets are risky, in case of ingestion, which becomes key in the context of child health protection. It is also worth noting that small elements of these magnets are able to disrupt the diagnostic process medical after entering the body.
• High unit price – neodymium magnets have a higher price than other types of magnets (e.g. ferrite), which hinders application in large quantities

Best holding force of the magnet in ideal parameters – what contributes to it?

Holding force of 280 kg is a result of laboratory testing performed under specific, ideal conditions:

• on a plate made of mild steel, perfectly concentrating the magnetic flux
• whose thickness reaches at least 10 mm
• with a surface cleaned and smooth
• under conditions of ideal adhesion (surface-to-surface)
• during detachment in a direction vertical to the mounting surface
• in neutral thermal conditions

Determinants of practical lifting force of a magnet

Please note that the magnet holding may be lower subject to the following factors, starting with the most relevant:

• Air gap (between the magnet and the metal), as even a tiny clearance (e.g. 0.5 mm) leads to a drastic drop in lifting capacity by up to 50% (this also applies to paint, corrosion or dirt).
• Angle of force application – highest force is obtained only during pulling at a 90° angle. The force required to slide of the magnet along the surface is usually several times lower (approx. 1/5 of the lifting capacity).
• Plate thickness – insufficiently thick plate causes magnetic saturation, causing part of the flux to be escaped to the other side.
• Material type – ideal substrate is pure iron steel. Stainless steels may have worse magnetic properties.
• Surface condition – ground elements guarantee perfect abutment, which improves force. Uneven metal reduce efficiency.
• Thermal environment – heating the magnet results in weakening of induction. It is worth remembering the thermal limit for a given model.

* Holding force was checked on the plate surface of 20 mm thickness, when a perpendicular force was applied, whereas under attempts to slide the magnet the holding force is lower. Additionally, even a small distance {between} the magnet and the plate decreases the holding force.