MPL 40x18x10 SH / N38 - lamellar magnet

Strengths as well as weaknesses of rare earth magnets.

In addition to their magnetic efficiency, neodymium magnets provide the following advantages:

• They retain full power for almost ten 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 reflective surface of silver, the element gains visual value,
• They feature high magnetic induction at the operating surface, which increases their power,
• Due to their durability and thermal resistance, neodymium magnets can operate (depending on the form) even at high temperatures reaching 230°C or more...
• Thanks to versatility in shaping and the capacity to customize to specific needs,
• Versatile presence in future technologies – they are used in HDD drives, electric drive systems, medical equipment, and other advanced devices.
• Relatively small size with high pulling force – neodymium magnets offer strong magnetic field in tiny dimensions, which enables their usage in small systems

Disadvantages of neodymium magnets:

• They are prone to damage upon too strong impacts. To avoid cracks, it is worth securing magnets in a protective case. Such protection not only shields the magnet but also improves its resistance to damage
• NdFeB magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop of strength (a factor is the shape and dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are very resistant to heat
• Due to the susceptibility of magnets to corrosion in a humid environment, we suggest using waterproof magnets made of rubber, plastic or other material stable to moisture, when using outdoors
• We recommend cover - magnetic holder, due to difficulties in creating threads inside the magnet and complicated shapes.
• Potential hazard to health – tiny shards of magnets can be dangerous, in case of ingestion, which becomes key in the context of child health protection. It is also worth noting that small components of these devices can be problematic in diagnostics medical in case of swallowing.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Maximum holding power of the magnet – what it depends on?

The lifting capacity listed is a measurement result performed under specific, ideal conditions:

• on a base made of mild steel, optimally conducting the magnetic field
• possessing a massiveness of minimum 10 mm to avoid saturation
• characterized by smoothness
• without any insulating layer between the magnet and steel
• during pulling in a direction perpendicular to the plane
• in temp. approx. 20°C

Lifting capacity in real conditions – factors

Holding efficiency is affected by working environment parameters, such as (from most important):

• Distance (betwixt the magnet and the metal), because even a very small clearance (e.g. 0.5 mm) leads to a decrease in lifting capacity by up to 50% (this also applies to varnish, rust or debris).
• Force direction – note that the magnet has greatest strength perpendicularly. Under sliding down, the holding force drops significantly, often to levels of 20-30% of the maximum value.
• Substrate thickness – to utilize 100% power, the steel must be sufficiently thick. Paper-thin metal restricts the attraction force (the magnet "punches through" it).
• Chemical composition of the base – low-carbon steel gives the best results. Alloy admixtures lower magnetic permeability and holding force.
• Surface structure – the more even the plate, the larger the contact zone and stronger the hold. Roughness acts like micro-gaps.
• Temperature influence – hot environment weakens magnetic field. Too high temperature can permanently damage the magnet.

* Holding force was measured on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, however under attempts to slide the magnet the lifting capacity is smaller. Additionally, even a slight gap {between} the magnet’s surface and the plate reduces the lifting capacity.