SM 25x275 [2xM8] / N52 - magnetic separator

Strengths as well as weaknesses of rare earth magnets.

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

• They virtually do not lose strength, because even after 10 years the performance loss is only ~1% (in laboratory conditions),
• Magnets perfectly resist against demagnetization caused by foreign field sources,
• The use of an aesthetic coating of noble metals (nickel, gold, silver) causes the element to have aesthetics,
• Magnets have maximum magnetic induction on the outer layer,
• Through (appropriate) combination of ingredients, they can achieve high thermal strength, allowing for functioning at temperatures reaching 230°C and above...
• Considering the ability of flexible shaping and adaptation to specialized projects, NdFeB magnets can be produced in a wide range of geometric configurations, which expands the range of possible applications,
• Significant place in innovative solutions – they are utilized in data components, electromotive mechanisms, advanced medical instruments, also multitasking production systems.
• Thanks to their power density, small magnets offer high operating force, occupying minimum space,

Drawbacks and weaknesses of neodymium magnets: application proposals

• At strong impacts they can break, therefore we advise placing them in special holders. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• We warn that neodymium magnets can lose their power at high temperatures. To prevent this, we suggest our specialized [AH] magnets, which work effectively even at 230°C.
• Magnets exposed to a humid environment can corrode. Therefore when using outdoors, we advise using waterproof magnets made of rubber, plastic or other material protecting against moisture
• Limited ability of making nuts in the magnet and complex forms - recommended is casing - magnet mounting.
• Potential hazard resulting from small fragments of magnets can be dangerous, when accidentally swallowed, which becomes key in the aspect of protecting the youngest. Furthermore, small elements of these devices can complicate diagnosis medical in case of swallowing.
• With mass production the cost of neodymium magnets can be a barrier,

Maximum magnetic pulling force – what it depends on?

The load parameter shown concerns the maximum value, obtained under optimal environment, meaning:

• using a plate made of low-carbon steel, acting as a ideal flux conductor
• whose transverse dimension equals approx. 10 mm
• with an ideally smooth touching surface
• without the slightest insulating layer between the magnet and steel
• for force applied at a right angle (in the magnet axis)
• at standard ambient temperature

Key elements affecting lifting force

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

• Distance – the presence of any layer (paint, dirt, air) interrupts the magnetic circuit, which reduces power steeply (even by 50% at 0.5 mm).
• Direction of force – maximum parameter is obtained only during perpendicular pulling. The shear force of the magnet along the surface is standardly several times smaller (approx. 1/5 of the lifting capacity).
• Substrate thickness – for full efficiency, the steel must be sufficiently thick. Thin sheet restricts the lifting capacity (the magnet "punches through" it).
• Material type – the best choice is high-permeability steel. Cast iron may generate lower lifting capacity.
• Surface finish – full contact is obtained only on polished steel. Rough texture reduce the real contact area, reducing force.
• Thermal factor – hot environment reduces pulling force. Too high temperature can permanently damage the magnet.

* Holding force was checked on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, in contrast under attempts to slide the magnet the holding force is lower. Additionally, even a small distance {between} the magnet’s surface and the plate lowers the holding force.