SM 32x500 [2xM8] / N52 - magnetic separator

Advantages and disadvantages of NdFeB magnets.

Besides their tremendous magnetic power, neodymium magnets offer the following advantages:

• Their strength remains stable, and after approximately ten years it drops only by ~1% (according to research),
• Magnets very well defend themselves against loss of magnetization caused by foreign field sources,
• A magnet with a smooth nickel surface has better aesthetics,
• They show high magnetic induction at the operating surface, which increases their power,
• Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the form) even at high temperatures reaching 230°C or more...
• Possibility of precise shaping and modifying to individual needs,
• Huge importance in modern industrial fields – they are utilized in mass storage devices, drive modules, medical devices, and industrial machines.
• Thanks to concentrated force, small magnets offer high operating force, with minimal size,

Disadvantages of NdFeB magnets:

• They are prone to damage upon too strong impacts. To avoid cracks, it is worth securing magnets in a protective case. Such protection not only shields the magnet but also increases its resistance to damage
• NdFeB magnets lose strength 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
• Magnets exposed to a humid environment can corrode. Therefore during using outdoors, we advise using waterproof magnets made of rubber, plastic or other material protecting against moisture
• We recommend casing - magnetic mechanism, due to difficulties in realizing nuts inside the magnet and complex shapes.
• Potential hazard resulting from small fragments of magnets pose a threat, in case of ingestion, which gains importance in the context of child health protection. Furthermore, small elements of these magnets are able to be problematic in diagnostics medical when they are in the body.
• High unit price – neodymium magnets cost more than other types of magnets (e.g. ferrite), which hinders application in large quantities

Best holding force of the magnet in ideal parameters – what affects it?

Magnet power was determined for the most favorable conditions, taking into account:

• on a base made of mild steel, optimally conducting the magnetic flux
• with a cross-section no less than 10 mm
• with an ideally smooth contact surface
• without the slightest clearance between the magnet and steel
• for force applied at a right angle (in the magnet axis)
• at room temperature

Key elements affecting lifting force

During everyday use, the actual holding force results from several key aspects, presented from most significant:

• Clearance – existence of foreign body (rust, dirt, gap) interrupts the magnetic circuit, which lowers capacity steeply (even by 50% at 0.5 mm).
• Direction of force – highest force is reached only during pulling at a 90° angle. The shear force of the magnet along the surface is typically several times smaller (approx. 1/5 of the lifting capacity).
• Substrate thickness – for full efficiency, the steel must be sufficiently thick. Thin sheet limits the lifting capacity (the magnet "punches through" it).
• Material composition – not every steel attracts identically. High carbon content worsen the attraction effect.
• Smoothness – ideal contact is possible only on polished steel. Rough texture create air cushions, reducing force.
• Temperature influence – high temperature reduces magnetic field. Exceeding the limit temperature can permanently damage the magnet.

* Lifting capacity was determined by applying a smooth steel plate of suitable thickness (min. 20 mm), under perpendicular detachment force, whereas under attempts to slide the magnet the lifting capacity is smaller. In addition, even a small distance {between} the magnet and the plate reduces the holding force.