SM 32x450 [2xM8] / N42 - magnetic separator

Strengths as well as weaknesses of NdFeB magnets.

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

• They retain full power for nearly ten years – the loss is just ~1% (in theory),
• They are noted for resistance to demagnetization induced by external disturbances,
• A magnet with a metallic nickel surface looks better,
• Neodymium magnets deliver maximum magnetic induction on a contact point, which increases force concentration,
• Due to their durability and thermal resistance, neodymium magnets can operate (depending on the form) even at high temperatures reaching 230°C or more...
• Possibility of precise modeling as well as adapting to specific requirements,
• Fundamental importance in future technologies – they serve a role in HDD drives, electric drive systems, medical equipment, also complex engineering applications.
• Compactness – despite small sizes they provide effective action, making them ideal for precision applications

Disadvantages of neodymium magnets:

• At strong impacts they can crack, therefore we advise placing them in steel cases. A metal housing provides additional protection against damage and increases the magnet's durability.
• We warn that neodymium magnets can reduce their strength at high temperatures. To prevent this, we advise our specialized [AH] magnets, which work effectively even at 230°C.
• Due to the susceptibility of magnets to corrosion in a humid environment, we suggest using waterproof magnets made of rubber, plastic or other material stable to moisture, in case of application outdoors
• Limited ability of making nuts in the magnet and complex forms - recommended is casing - mounting mechanism.
• Possible danger related to microscopic parts of magnets can be dangerous, when accidentally swallowed, which gains importance in the context of child health protection. It is also worth noting that small elements of these magnets are able to be problematic in diagnostics medical after entering the body.
• High unit price – neodymium magnets have a higher price than other types of magnets (e.g. ferrite), which hinders application in large quantities

Maximum lifting capacity of the magnet – what contributes to it?

The specified lifting capacity represents the limit force, obtained under ideal test conditions, meaning:

• with the application of a yoke made of low-carbon steel, guaranteeing full magnetic saturation
• with a thickness of at least 10 mm
• with a surface cleaned and smooth
• with zero gap (no paint)
• for force acting at a right angle (pull-off, not shear)
• at standard ambient temperature

Lifting capacity in practice – influencing factors

Real force is influenced by specific conditions, mainly (from priority):

• Space between magnet and steel – even a fraction of a millimeter of distance (caused e.g. by varnish or unevenness) significantly weakens the magnet efficiency, often by half at just 0.5 mm.
• Pull-off angle – remember that the magnet has greatest strength perpendicularly. Under sliding down, the capacity drops drastically, often to levels of 20-30% of the nominal value.
• Base massiveness – insufficiently thick steel does not accept the full field, causing part of the flux to be escaped to the other side.
• Steel grade – the best choice is high-permeability steel. Hardened steels may have worse magnetic properties.
• Plate texture – smooth surfaces guarantee perfect abutment, which increases force. Uneven metal weaken the grip.
• Temperature – temperature increase results in weakening of induction. Check the thermal limit for a given model.

* Holding force was measured on the plate surface of 20 mm thickness, when the force acted perpendicularly, whereas under parallel forces the load capacity is reduced by as much as fivefold. Moreover, even a minimal clearance {between} the magnet and the plate decreases the holding force.