MPL 40x10x5x2[7/3.5] / N38 - lamellar magnet

Advantages and disadvantages of rare earth magnets.

Besides their tremendous field intensity, neodymium magnets offer the following advantages:

• They have constant strength, and over around 10 years their performance decreases symbolically – ~1% (in testing),
• They retain their magnetic properties even under external field action,
• By covering with a decorative coating of silver, the element acquires an modern look,
• They show high magnetic induction at the operating surface, which increases their power,
• Through (adequate) combination of ingredients, they can achieve high thermal resistance, enabling operation at temperatures approaching 230°C and above...
• Thanks to flexibility in designing and the capacity to modify to unusual requirements,
• Key role in innovative solutions – they serve a role in magnetic memories, electric motors, medical equipment, and modern systems.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Disadvantages of neodymium magnets:

• At strong impacts they can crack, therefore we recommend placing them in strong housings. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• Neodymium magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop of power (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 extremely resistant to heat
• Due to the susceptibility of magnets to corrosion in a humid environment, we recommend using waterproof magnets made of rubber, plastic or other material stable to moisture, when using outdoors
• Due to limitations in creating threads and complex shapes in magnets, we recommend using casing - magnetic mechanism.
• Potential hazard resulting from small fragments of magnets are risky, when accidentally swallowed, which becomes key in the aspect of protecting the youngest. Additionally, small elements of these devices can be problematic in diagnostics medical in case of swallowing.
• With budget limitations the cost of neodymium magnets is economically unviable,

Magnetic strength at its maximum – what it depends on?

Holding force of 7.9 kg is a measurement result performed under standard conditions:

• on a block made of structural steel, perfectly concentrating the magnetic field
• possessing a massiveness of min. 10 mm to avoid saturation
• characterized by smoothness
• under conditions of no distance (metal-to-metal)
• during pulling in a direction perpendicular to the mounting surface
• at room temperature

Impact of factors on magnetic holding capacity in practice

Holding efficiency is affected by specific conditions, such as (from most important):

• Space between magnet and steel – even a fraction of a millimeter of separation (caused e.g. by varnish or unevenness) drastically reduces the magnet efficiency, often by half at just 0.5 mm.
• Direction of force – highest force is obtained only during perpendicular pulling. The shear force of the magnet along the surface is typically many times smaller (approx. 1/5 of the lifting capacity).
• Substrate thickness – for full efficiency, the steel must be adequately massive. Paper-thin metal restricts the attraction force (the magnet "punches through" it).
• Material composition – not every steel attracts identically. Alloy additives worsen the interaction with the magnet.
• Smoothness – full contact is obtained only on polished steel. Any scratches and bumps reduce the real contact area, reducing force.
• Thermal factor – hot environment reduces pulling force. Too high temperature can permanently damage the magnet.

* Lifting capacity testing was performed on plates with a smooth surface of suitable thickness, under perpendicular forces, whereas under attempts to slide the magnet the load capacity is reduced by as much as 5 times. In addition, even a small distance {between} the magnet’s surface and the plate reduces the lifting capacity.