SM 25x325 [2xM8] / N52 - magnetic separator

Pros as well as cons of NdFeB magnets.

Apart from their strong magnetism, neodymium magnets have these key benefits:

• They retain full power for nearly 10 years – the loss is just ~1% (according to analyses),
• They feature excellent resistance to weakening of magnetic properties as a result of external magnetic sources,
• A magnet with a shiny nickel surface looks better,
• They are known for high magnetic induction at the operating surface, which improves attraction properties,
• Due to their durability and thermal resistance, neodymium magnets can operate (depending on the shape) even at high temperatures reaching 230°C or more...
• Possibility of accurate shaping as well as optimizing to concrete requirements,
• Wide application in high-tech industry – they are used in hard drives, electromotive mechanisms, precision medical tools, and complex engineering applications.
• Relatively small size with high pulling force – neodymium magnets offer strong magnetic field in tiny dimensions, which makes them useful in compact constructions

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 and increases the magnet's durability.
• Neodymium magnets lose power 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
• They oxidize in a humid environment - during use outdoors we suggest using waterproof magnets e.g. in rubber, plastic
• Due to limitations in realizing threads and complex forms in magnets, we propose using casing - magnetic holder.
• Potential hazard related to microscopic parts of magnets can be dangerous, when accidentally swallowed, which gains importance in the context of child safety. It is also worth noting that small elements of these products are able to complicate diagnosis medical when they are in the body.
• High unit price – neodymium magnets have a higher price 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 load parameter shown refers to the limit force, measured under optimal environment, namely:

• using a plate made of high-permeability steel, acting as a circuit closing element
• with a thickness minimum 10 mm
• characterized by even structure
• with total lack of distance (no coatings)
• for force applied at a right angle (in the magnet axis)
• at room temperature

Determinants of practical lifting force of a magnet

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

• Gap between surfaces – every millimeter of separation (caused e.g. by veneer or unevenness) diminishes the magnet efficiency, often by half at just 0.5 mm.
• Pull-off angle – note that the magnet holds strongest perpendicularly. Under sliding down, the holding force drops significantly, often to levels of 20-30% of the maximum value.
• Base massiveness – insufficiently thick sheet does not close the flux, causing part of the flux to be escaped to the other side.
• Metal type – not every steel attracts identically. High carbon content weaken the attraction effect.
• Surface condition – ground elements ensure maximum contact, which increases force. Uneven metal weaken the grip.
• Temperature – temperature increase causes a temporary drop of induction. It is worth remembering the thermal limit for a given model.

* Holding force was tested on the plate surface of 20 mm thickness, when the force acted perpendicularly, in contrast under attempts to slide the magnet the lifting capacity is smaller. Additionally, even a slight gap {between} the magnet and the plate reduces the holding force.