SMZR 25x200 / N52 - magnetic separator with handle

Pros and cons of rare earth magnets.

Besides their magnetic performance, neodymium magnets are valued for these benefits:

• Their power is durable, and after approximately ten years it drops only by ~1% (according to research),
• They do not lose their magnetic properties even under strong external field,
• A magnet with a smooth silver surface looks better,
• Magnetic induction on the surface of the magnet remains exceptional,
• 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...
• Thanks to versatility in constructing and the ability to customize to complex applications,
• Key role in innovative solutions – they are utilized in hard drives, brushless drives, medical equipment, and complex engineering applications.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Cons of neodymium magnets: application proposals

• 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.
• We warn that neodymium magnets can lose their strength at high temperatures. To prevent this, we recommend our specialized [AH] magnets, which work effectively even at 230°C.
• They rust in a humid environment. For use outdoors we advise using waterproof magnets e.g. in rubber, plastic
• Limited ability of producing threads in the magnet and complicated forms - recommended is a housing - mounting mechanism.
• Health risk related to microscopic parts of magnets are risky, if swallowed, which gains importance in the context of child safety. It is also worth noting that small elements of these magnets are able to disrupt the diagnostic process medical when they are in the body.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Maximum magnetic pulling force – what it depends on?

The force parameter is a theoretical maximum value performed under specific, ideal conditions:

• on a block made of mild steel, perfectly concentrating the magnetic field
• possessing a thickness of min. 10 mm to avoid saturation
• with a plane cleaned and smooth
• without any clearance between the magnet and steel
• for force acting at a right angle (pull-off, not shear)
• in temp. approx. 20°C

What influences lifting capacity in practice

Effective lifting capacity impacted by working environment parameters, including (from most important):

• Clearance – the presence of any layer (rust, tape, air) interrupts the magnetic circuit, which reduces capacity rapidly (even by 50% at 0.5 mm).
• Force direction – remember that the magnet has greatest strength perpendicularly. Under sliding down, the holding force drops drastically, often to levels of 20-30% of the nominal value.
• Wall thickness – thin material does not allow full use of the magnet. Part of the magnetic field passes through the material instead of generating force.
• Chemical composition of the base – low-carbon steel gives the best results. Alloy admixtures lower magnetic permeability and lifting capacity.
• Surface condition – smooth surfaces ensure maximum contact, which increases force. Uneven metal weaken the grip.
• Heat – neodymium magnets have a negative temperature coefficient. When it is hot they lose power, and in frost gain strength (up to a certain limit).

* Lifting capacity testing was conducted on a smooth plate of optimal thickness, under perpendicular forces, however under parallel forces the holding force is lower. In addition, even a minimal clearance {between} the magnet and the plate decreases the load capacity.