UMS 16x6.5x3.5x5 / N38 - conical magnetic holder

Pros and cons of rare earth magnets.

Besides their immense pulling force, neodymium magnets offer the following advantages:

• They have constant strength, and over more than 10 years their attraction force decreases symbolically – ~1% (in testing),
• They possess excellent resistance to magnetic field loss when exposed to opposing magnetic fields,
• A magnet with a shiny silver surface has an effective appearance,
• Magnets exhibit exceptionally strong magnetic induction on the outer side,
• These magnets tolerate extreme temperatures, often exceeding 230°C, when properly designed (in relation to form),
• Thanks to versatility in shaping and the capacity to modify to specific needs,
• Wide application in advanced technology sectors – they are utilized in HDD drives, electromotive mechanisms, advanced medical instruments, and modern systems.
• Relatively small size with high pulling force – neodymium magnets offer impressive pulling force in tiny dimensions, which enables their usage in miniature devices

Cons of neodymium magnets: application proposals

• To avoid cracks upon strong impacts, we suggest using special steel holders. Such a solution protects the magnet and simultaneously increases its 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 start to rust. For applications outside, it is recommended to use protective magnets, such as those in rubber or plastics, which secure oxidation as well as corrosion.
• Limited ability of creating nuts in the magnet and complex shapes - preferred is casing - mounting mechanism.
• Possible danger related to microscopic parts of magnets can be dangerous, when accidentally swallowed, which is particularly important in the aspect of protecting the youngest. It is also worth noting that small components of these devices can disrupt the diagnostic process medical after entering the body.
• High unit price – neodymium magnets are more expensive than other types of magnets (e.g. ferrite), which hinders application in large quantities

Maximum magnetic pulling force – what affects it?

The force parameter is a measurement result executed under specific, ideal conditions:

• on a plate made of structural steel, perfectly concentrating the magnetic field
• with a thickness no less than 10 mm
• with a plane cleaned and smooth
• without the slightest insulating layer between the magnet and steel
• under axial application of breakaway force (90-degree angle)
• at temperature room level

Practical lifting capacity: influencing factors

Real force impacted by specific conditions, including (from priority):

• Clearance – the presence of any layer (rust, dirt, air) interrupts the magnetic circuit, which lowers power steeply (even by 50% at 0.5 mm).
• Force direction – declared lifting capacity refers to detachment vertically. When slipping, the magnet exhibits much less (often approx. 20-30% of maximum force).
• Metal thickness – the thinner the sheet, the weaker the hold. Part of the magnetic field passes through the material instead of converting into lifting capacity.
• Material type – the best choice is pure iron steel. Stainless steels may attract less.
• Plate texture – ground elements ensure maximum contact, which improves force. Rough surfaces reduce efficiency.
• Temperature influence – hot environment reduces magnetic field. Exceeding the limit temperature can permanently demagnetize the magnet.

* Holding force was tested on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, in contrast under shearing force the holding force is lower. Moreover, even a small distance {between} the magnet’s surface and the plate decreases the load capacity.