SM 32x500 [2xM8] / N52 - magnetic separator

Advantages and disadvantages of neodymium magnets.

Apart from their strong holding force, neodymium magnets have these key benefits:

• They have constant strength, and over around ten years their performance decreases symbolically – ~1% (in testing),
• They do not lose their magnetic properties even under strong external field,
• The use of an metallic finish of noble metals (nickel, gold, silver) causes the element to present itself better,
• The surface of neodymium magnets generates a strong magnetic field – this is a key feature,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their form) at temperatures up to 230°C and above...
• Thanks to flexibility in constructing and the ability to modify to complex applications,
• Key role in high-tech industry – they are used in data components, motor assemblies, medical devices, also industrial machines.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Disadvantages of neodymium magnets:

• Brittleness is one of their disadvantages. Upon strong impact they can break. We recommend keeping them in a special holder, which not only protects them against impacts but also increases their durability
• When exposed to high temperature, neodymium magnets experience a drop in strength. Often, when the temperature exceeds 80°C, their power decreases (depending on the size and shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
• Due to the susceptibility of magnets to corrosion in a humid environment, we advise using waterproof magnets made of rubber, plastic or other material resistant to moisture, when using outdoors
• Limited possibility of making threads in the magnet and complex shapes - recommended is a housing - mounting mechanism.
• Health risk resulting from small fragments of magnets pose a threat, when accidentally swallowed, which gains importance in the context of child health protection. Furthermore, tiny parts of these magnets are able to complicate diagnosis medical when they are in the body.
• With mass production the cost of neodymium magnets can be a barrier,

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

Magnet power is the result of a measurement for ideal contact conditions, assuming:

• using a sheet made of high-permeability steel, acting as a magnetic yoke
• with a cross-section no less than 10 mm
• with a plane perfectly flat
• with direct contact (without paint)
• during detachment in a direction perpendicular to the mounting surface
• at room temperature

Key elements affecting lifting force

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

• Clearance – existence of any layer (rust, dirt, gap) interrupts the magnetic circuit, which reduces capacity rapidly (even by 50% at 0.5 mm).
• Pull-off angle – remember that the magnet holds strongest perpendicularly. Under shear forces, the capacity 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 limits the attraction force (the magnet "punches through" it).
• Steel grade – ideal substrate is pure iron steel. Hardened steels may have worse magnetic properties.
• Surface condition – smooth surfaces ensure maximum contact, which improves field saturation. Uneven metal weaken the grip.
• Thermal conditions – NdFeB sinters have a sensitivity to temperature. At higher temperatures they are weaker, and at low temperatures they can be stronger (up to a certain limit).

* Lifting capacity was determined using a steel plate with a smooth surface of suitable thickness (min. 20 mm), under perpendicular detachment force, in contrast under parallel forces the load capacity is reduced by as much as fivefold. In addition, even a minimal clearance {between} the magnet and the plate reduces the load capacity.