MPL 25x10x5 / N38 - lamellar magnet

Advantages as well as disadvantages of neodymium magnets.

Apart from their superior magnetic energy, neodymium magnets have these key benefits:

• Their power is maintained, and after approximately ten years it decreases only by ~1% (theoretically),
• They have excellent resistance to magnetic field loss when exposed to opposing magnetic fields,
• In other words, due to the aesthetic layer of nickel, the element gains visual value,
• Neodymium magnets generate maximum magnetic induction on a small surface, which increases force concentration,
• Through (appropriate) combination of ingredients, they can achieve high thermal resistance, enabling operation at temperatures reaching 230°C and above...
• Thanks to flexibility in forming and the ability to adapt to specific needs,
• Significant place in electronics industry – they are commonly used in HDD drives, electric drive systems, diagnostic systems, as well as multitasking production systems.
• Thanks to their power density, small magnets offer high operating force, occupying minimum space,

Disadvantages of NdFeB magnets:

• At very strong impacts they can crack, therefore we recommend placing them in special holders. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• Neodymium magnets lose their strength 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 - during use outdoors we advise using waterproof magnets e.g. in rubber, plastic
• We recommend casing - magnetic holder, due to difficulties in realizing nuts inside the magnet and complex shapes.
• Potential hazard resulting from small fragments of magnets are risky, in case of ingestion, which gains importance in the aspect of protecting the youngest. Additionally, tiny parts of these magnets are able to disrupt the diagnostic process medical in case of swallowing.
• Due to expensive raw materials, their price is higher than average,

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

Magnet power was defined for optimal configuration, including:

• using a sheet made of mild steel, acting as a ideal flux conductor
• possessing a thickness of minimum 10 mm to avoid saturation
• characterized by smoothness
• under conditions of no distance (surface-to-surface)
• during pulling in a direction vertical to the plane
• at conditions approx. 20°C

What influences lifting capacity in practice

Effective lifting capacity is influenced by specific conditions, including (from most important):

• Gap between surfaces – every millimeter of separation (caused e.g. by veneer or dirt) significantly weakens the pulling force, often by half at just 0.5 mm.
• Direction of force – maximum parameter is reached only during perpendicular pulling. The resistance to sliding of the magnet along the plate is typically many times smaller (approx. 1/5 of the lifting capacity).
• Metal 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.
• Metal type – different alloys attracts identically. Alloy additives weaken the attraction effect.
• Surface quality – the more even the plate, the larger the contact zone and higher the lifting capacity. Roughness acts like micro-gaps.
• Thermal factor – hot environment reduces magnetic field. Too high temperature can permanently demagnetize the magnet.

* Lifting capacity was measured by applying a polished steel plate of optimal thickness (min. 20 mm), under perpendicular detachment force, whereas under shearing force the holding force is lower. Moreover, even a minimal clearance {between} the magnet’s surface and the plate reduces the lifting capacity.