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

Pros as well as cons of rare earth magnets.

In addition to their long-term stability, neodymium magnets provide the following advantages:

• Their power is maintained, and after around 10 years it drops only by ~1% (theoretically),
• They do not lose their magnetic properties even under strong external field,
• In other words, due to the aesthetic surface of gold, the element gains a professional look,
• Magnets possess exceptionally strong magnetic induction on the active area,
• Through (appropriate) combination of ingredients, they can achieve high thermal strength, enabling action at temperatures approaching 230°C and above...
• Possibility of custom shaping as well as adapting to specific applications,
• Fundamental importance in innovative solutions – they are commonly used in computer drives, electric drive systems, medical devices, also complex engineering applications.
• Thanks to efficiency per cm³, small magnets offer high operating force, in miniature format,

Cons of neodymium magnets and proposals for their use:

• At very strong impacts they can break, therefore we advise placing them in strong housings. A metal housing provides additional protection against damage and increases the magnet's durability.
• When exposed to high temperature, neodymium magnets experience a drop in force. Often, when the temperature exceeds 80°C, their power decreases (depending on the size and shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
• Magnets exposed to a humid environment can rust. Therefore during using outdoors, we advise using waterproof magnets made of rubber, plastic or other material protecting against moisture
• Limited ability of creating threads in the magnet and complicated shapes - preferred is casing - magnet mounting.
• Health risk to health – tiny shards of magnets pose a threat, if swallowed, which is particularly important in the context of child health protection. Additionally, tiny parts of these devices can complicate diagnosis medical after entering the body.
• With large orders the cost of neodymium magnets can be a barrier,

Maximum lifting force for a neodymium magnet – what affects it?

Information about lifting capacity was determined for optimal configuration, taking into account:

• with the contact of a sheet made of special test steel, ensuring maximum field concentration
• possessing a thickness of at least 10 mm to ensure full flux closure
• with a plane perfectly flat
• without any air gap between the magnet and steel
• during pulling in a direction vertical to the mounting surface
• in temp. approx. 20°C

Determinants of lifting force in real conditions

It is worth knowing that the magnet holding may be lower subject to elements below, starting with the most relevant:

• Gap (betwixt the magnet and the metal), as even a very small clearance (e.g. 0.5 mm) can cause a decrease in lifting capacity by up to 50% (this also applies to paint, corrosion or dirt).
• Load vector – maximum parameter is reached only during perpendicular pulling. The shear force of the magnet along the surface is typically several times smaller (approx. 1/5 of the lifting capacity).
• Element thickness – to utilize 100% power, the steel must be adequately massive. Thin sheet restricts the attraction force (the magnet "punches through" it).
• Material composition – different alloys attracts identically. High carbon content weaken the interaction with the magnet.
• Surface structure – the smoother and more polished the plate, the larger the contact zone and stronger the hold. Unevenness creates an air distance.
• Thermal factor – high temperature reduces pulling force. Too high temperature can permanently damage the magnet.

* Holding force was measured on the plate surface of 20 mm thickness, when the force acted perpendicularly, however under shearing force the load capacity is reduced by as much as 75%. In addition, even a minimal clearance {between} the magnet and the plate decreases the lifting capacity.