SM 32x350 [2xM8] / N52 - magnetic separator

Strengths and weaknesses of NdFeB magnets.

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

• They do not lose power, even over approximately ten years – the decrease in power is only ~1% (theoretically),
• Magnets effectively defend themselves against loss of magnetization caused by external fields,
• A magnet with a metallic gold surface has better aesthetics,
• They show high magnetic induction at the operating surface, which increases their power,
• Through (appropriate) combination of ingredients, they can achieve high thermal resistance, enabling action at temperatures approaching 230°C and above...
• Possibility of accurate forming as well as adjusting to specific needs,
• Wide application in innovative solutions – they serve a role in magnetic memories, drive modules, medical devices, also multitasking production systems.
• Thanks to their power density, small magnets offer high operating force, with minimal size,

Disadvantages of neodymium magnets:

• At strong impacts they can break, therefore we advise placing them in strong housings. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• We warn that neodymium magnets can reduce 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 rust. Therefore when using outdoors, we advise using waterproof magnets made of rubber, plastic or other material protecting against moisture
• Due to limitations in realizing threads and complex forms in magnets, we recommend using casing - magnetic mechanism.
• Health risk resulting from small fragments of magnets can be dangerous, in case of ingestion, which gains importance in the aspect of protecting the youngest. It is also worth noting that small elements of these magnets are able to complicate diagnosis 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

Highest magnetic holding force – what it depends on?

The force parameter is a theoretical maximum value performed under the following configuration:

• using a base made of high-permeability steel, functioning as a magnetic yoke
• whose thickness is min. 10 mm
• with an ideally smooth touching surface
• without any clearance between the magnet and steel
• under vertical force vector (90-degree angle)
• at temperature room level

Impact of factors on magnetic holding capacity in practice

Effective lifting capacity is affected by specific conditions, mainly (from most important):

• Clearance – existence of foreign body (rust, dirt, air) interrupts the magnetic circuit, which lowers capacity rapidly (even by 50% at 0.5 mm).
• Pull-off angle – note that the magnet holds strongest perpendicularly. Under shear forces, the holding force drops drastically, often to levels of 20-30% of the nominal value.
• Element thickness – to utilize 100% power, the steel must be sufficiently thick. Paper-thin metal restricts the attraction force (the magnet "punches through" it).
• Material composition – different alloys reacts the same. Alloy additives worsen the attraction effect.
• Surface structure – the smoother and more polished the surface, the better the adhesion and higher the lifting capacity. Roughness acts like micro-gaps.
• Thermal conditions – NdFeB sinters have a sensitivity to temperature. At higher temperatures they are weaker, and in frost gain strength (up to a certain limit).

* Lifting capacity was assessed with the use of a steel plate with a smooth surface of suitable thickness (min. 20 mm), under perpendicular detachment force, in contrast under attempts to slide the magnet the holding force is lower. Additionally, even a small distance {between} the magnet and the plate reduces the load capacity.