SMZR 25x200 / N52 - magnetic separator with handle

Pros as well as cons of NdFeB magnets.

Besides their exceptional field intensity, neodymium magnets offer the following advantages:

• Their power remains stable, and after approximately ten years it drops only by ~1% (according to research),
• They retain their magnetic properties even under external field action,
• In other words, due to the aesthetic finish of silver, the element becomes visually attractive,
• They show high magnetic induction at the operating surface, which improves attraction properties,
• Through (appropriate) combination of ingredients, they can achieve high thermal resistance, allowing for functioning at temperatures approaching 230°C and above...
• Thanks to modularity in forming and the ability to modify to unusual requirements,
• Huge importance in innovative solutions – they find application in computer drives, drive modules, advanced medical instruments, also multitasking production systems.
• 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 special holders. A metal housing provides additional protection against damage and increases the magnet's 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.
• They oxidize in a humid environment. For use outdoors we suggest using waterproof magnets e.g. in rubber, plastic
• We recommend casing - magnetic mount, due to difficulties in creating nuts inside the magnet and complex forms.
• Potential hazard resulting from small fragments of magnets are risky, if swallowed, which becomes key in the aspect of protecting the youngest. Furthermore, small components of these products are able to be problematic in diagnostics medical in case of swallowing.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Maximum holding power of the magnet – what affects it?

The declared magnet strength represents the maximum value, recorded under ideal test conditions, specifically:

• on a base made of structural steel, perfectly concentrating the magnetic field
• with a thickness of at least 10 mm
• characterized by even structure
• with total lack of distance (without paint)
• during pulling in a direction perpendicular to the mounting surface
• at ambient temperature approx. 20 degrees Celsius

Impact of factors on magnetic holding capacity in practice

Holding efficiency impacted by working environment parameters, mainly (from most important):

• Gap between surfaces – even a fraction of a millimeter of distance (caused e.g. by varnish or dirt) drastically reduces the pulling force, often by half at just 0.5 mm.
• Direction of force – highest force is reached only during pulling at a 90° angle. The force required to slide of the magnet along the surface is typically many times lower (approx. 1/5 of the lifting capacity).
• Substrate thickness – to utilize 100% power, the steel must be sufficiently thick. Paper-thin metal restricts the attraction force (the magnet "punches through" it).
• Metal type – different alloys reacts the same. Alloy additives weaken the attraction effect.
• Surface finish – ideal contact is obtained only on polished steel. Any scratches and bumps create air cushions, reducing force.
• Temperature influence – high temperature weakens magnetic field. Exceeding the limit temperature can permanently demagnetize the magnet.

* Holding force was checked on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, whereas under shearing force the load capacity is reduced by as much as 75%. Additionally, even a slight gap {between} the magnet’s surface and the plate decreases the lifting capacity.