MW 14x10 / N38 - cylindrical magnet

Strengths as well as weaknesses of rare earth magnets.

Besides their high retention, neodymium magnets are valued for these benefits:

• They do not lose magnetism, even after nearly ten years – the decrease in strength is only ~1% (based on measurements),
• Neodymium magnets prove to be exceptionally resistant to demagnetization caused by external interference,
• Thanks to the shimmering finish, the plating of nickel, gold-plated, or silver-plated gives an clean appearance,
• They are known for high magnetic induction at the operating surface, which improves attraction properties,
• Through (adequate) combination of ingredients, they can achieve high thermal resistance, allowing for functioning at temperatures reaching 230°C and above...
• Possibility of exact shaping and optimizing to specific applications,
• Universal use in modern technologies – they serve a role in HDD drives, motor assemblies, precision medical tools, also industrial machines.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

What to avoid - cons of neodymium magnets: application proposals

• To avoid cracks upon strong impacts, we recommend using special steel housings. Such a solution secures the magnet and simultaneously increases its durability.
• We warn that neodymium magnets can reduce their strength at high temperatures. To prevent this, we advise 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.
• Limited possibility of creating nuts in the magnet and complex shapes - recommended is cover - magnet mounting.
• Health risk related to microscopic parts of magnets can be dangerous, when accidentally swallowed, which becomes key in the context of child safety. Additionally, tiny parts of these magnets can disrupt the diagnostic process medical in case of swallowing.
• High unit price – neodymium magnets cost more than other types of magnets (e.g. ferrite), which increases costs of application in large quantities

Breakaway strength of the magnet in ideal conditions – what it depends on?

The declared magnet strength concerns the peak performance, recorded under optimal environment, specifically:

• using a plate made of mild steel, functioning as a circuit closing element
• whose transverse dimension equals approx. 10 mm
• with a surface cleaned and smooth
• without the slightest clearance between the magnet and steel
• during detachment in a direction vertical to the plane
• at room temperature

Determinants of lifting force in real conditions

Holding efficiency impacted by working environment parameters, mainly (from most important):

• Distance – the presence of any layer (paint, tape, air) interrupts the magnetic circuit, which lowers power rapidly (even by 50% at 0.5 mm).
• Loading method – declared lifting capacity refers to detachment vertically. When attempting to slide, the magnet holds significantly lower power (typically approx. 20-30% of nominal force).
• Element thickness – for full efficiency, the steel must be adequately massive. Paper-thin metal restricts the lifting capacity (the magnet "punches through" it).
• Metal type – not every steel attracts identically. High carbon content worsen the interaction with the magnet.
• Smoothness – full contact is possible only on smooth steel. Rough texture create air cushions, reducing force.
• Temperature influence – high temperature weakens magnetic field. Too high temperature can permanently damage the magnet.

* Lifting capacity testing was performed on plates with a smooth surface of optimal thickness, under a perpendicular pulling force, in contrast under parallel forces the holding force is lower. Additionally, even a small distance {between} the magnet’s surface and the plate reduces the load capacity.