SM 32x225 [2xM8] / N52 - magnetic separator

Advantages and disadvantages of rare earth magnets.

Besides their high retention, neodymium magnets are valued for these benefits:

• They do not lose power, even during nearly ten years – the reduction in strength is only ~1% (based on measurements),
• Neodymium magnets are characterized by exceptionally resistant to magnetic field loss caused by magnetic disturbances,
• The use of an elegant finish of noble metals (nickel, gold, silver) causes the element to present itself better,
• They show high magnetic induction at the operating surface, which increases their power,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their form) at temperatures up to 230°C and above...
• Thanks to freedom in constructing and the ability to modify to individual projects,
• Wide application in modern technologies – they find application in magnetic memories, brushless drives, medical devices, also industrial machines.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• Brittleness is one of their disadvantages. Upon intense impact they can break. We recommend keeping them in a special holder, which not only protects them against impacts but also raises their durability
• We warn that neodymium magnets can lose their power at high temperatures. To prevent this, we recommend our specialized [AH] magnets, which work effectively even at 230°C.
• Magnets exposed to a humid environment can corrode. Therefore while using outdoors, we recommend using waterproof magnets made of rubber, plastic or other material protecting against moisture
• We recommend a housing - magnetic mechanism, due to difficulties in realizing threads inside the magnet and complicated forms.
• Potential hazard resulting from small fragments of magnets can be dangerous, when accidentally swallowed, which gains importance in the aspect of protecting the youngest. It is also worth noting that small components of these products are able to be problematic in diagnostics medical when they are in the body.
• With budget limitations the cost of neodymium magnets can be a barrier,

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

The specified lifting capacity concerns the limit force, obtained under laboratory conditions, meaning:

• with the use of a yoke made of low-carbon steel, ensuring maximum field concentration
• whose thickness reaches at least 10 mm
• with a surface free of scratches
• with zero gap (no coatings)
• for force acting at a right angle (in the magnet axis)
• at ambient temperature approx. 20 degrees Celsius

Practical lifting capacity: influencing factors

Real force is affected by specific conditions, including (from priority):

• Gap between magnet and steel – every millimeter of distance (caused e.g. by veneer or unevenness) drastically reduces the magnet efficiency, often by half at just 0.5 mm.
• Pull-off angle – remember that the magnet holds strongest perpendicularly. Under sliding down, the holding force drops significantly, often to levels of 20-30% of the maximum value.
• Substrate thickness – for full efficiency, the steel must be sufficiently thick. Paper-thin metal restricts the lifting capacity (the magnet "punches through" it).
• Material composition – not every steel reacts the same. Alloy additives weaken the attraction effect.
• Surface quality – the smoother and more polished the plate, the better the adhesion and higher the lifting capacity. Roughness creates an air distance.
• Temperature influence – high temperature reduces pulling force. Exceeding the limit temperature can permanently demagnetize the magnet.

* Holding force was tested on the plate surface of 20 mm thickness, when a perpendicular force was applied, whereas under shearing force the holding force is lower. In addition, even a small distance {between} the magnet and the plate reduces the lifting capacity.