SM 32x225 [2xM8] / N42 - magnetic separator

Pros as well as cons of neodymium magnets.

In addition to their magnetic efficiency, neodymium magnets provide the following advantages:

• They do not lose power, even during around ten years – the decrease in lifting capacity is only ~1% (based on measurements),
• Magnets perfectly protect themselves against loss of magnetization caused by ambient magnetic noise,
• The use of an aesthetic coating of noble metals (nickel, gold, silver) causes the element to have aesthetics,
• They are known for high magnetic induction at the operating surface, which improves attraction properties,
• Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and are able to act (depending on the shape) even at a temperature of 230°C or more...
• Thanks to modularity in forming and the ability to adapt to client solutions,
• Universal use in high-tech industry – they are used in data components, electric motors, advanced medical instruments, and industrial machines.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Disadvantages of neodymium magnets:

• At strong impacts they can break, therefore we recommend placing them in steel cases. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• Neodymium magnets decrease their strength under the influence of heating. As soon as 80°C is exceeded, many of them start losing their power. Therefore, we recommend our special magnets marked [AH], which maintain durability even at temperatures up to 230°C
• Due to the susceptibility of magnets to corrosion in a humid environment, we recommend using waterproof magnets made of rubber, plastic or other material immune to moisture, when using outdoors
• Limited ability of creating nuts in the magnet and complicated forms - preferred is cover - magnet mounting.
• Health risk resulting from small fragments of magnets are risky, if swallowed, which becomes key in the context of child safety. Additionally, small elements of these magnets can be problematic in diagnostics medical after entering the body.
• With budget limitations the cost of neodymium magnets can be a barrier,

Maximum holding power of the magnet – what contributes to it?

The specified lifting capacity refers to the limit force, recorded under optimal environment, specifically:

• with the contact of a yoke made of low-carbon steel, ensuring full magnetic saturation
• whose thickness reaches at least 10 mm
• with a plane perfectly flat
• under conditions of no distance (metal-to-metal)
• for force acting at a right angle (pull-off, not shear)
• at ambient temperature approx. 20 degrees Celsius

Practical lifting capacity: influencing factors

Bear in mind that the application force will differ subject to elements below, starting with the most relevant:

• Gap between surfaces – even a fraction of a millimeter of separation (caused e.g. by varnish or dirt) significantly weakens the pulling force, often by half at just 0.5 mm.
• Direction of force – maximum parameter is available only during pulling at a 90° angle. The shear force of the magnet along the surface is standardly many times smaller (approx. 1/5 of the lifting capacity).
• Base massiveness – insufficiently thick sheet does not accept the full field, causing part of the power to be wasted into the air.
• Material composition – different alloys attracts identically. Alloy additives weaken the interaction with the magnet.
• Base smoothness – the smoother and more polished the surface, the larger the contact zone and stronger the hold. Roughness acts like micro-gaps.
• Temperature – heating the magnet causes a temporary drop of induction. It is worth remembering the thermal limit for a given model.

* Holding force was measured on the plate surface of 20 mm thickness, when a perpendicular force was applied, in contrast under shearing force the lifting capacity is smaller. Moreover, even a small distance {between} the magnet and the plate lowers the load capacity.