SM 19x225 [2xM6] / N50 - magnetic separator

Pros as well as cons of NdFeB magnets.

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

• They retain attractive force for nearly 10 years – the loss is just ~1% (in theory),
• They are extremely resistant to demagnetization induced by presence of other magnetic fields,
• The use of an elegant coating of noble metals (nickel, gold, silver) causes the element to have aesthetics,
• The surface of neodymium magnets generates a maximum magnetic field – this is a key feature,
• These magnets tolerate high temperatures, often exceeding 230°C, when properly designed (in relation to profile),
• Possibility of detailed creating as well as optimizing to atypical requirements,
• Wide application in modern industrial fields – they are utilized in mass storage devices, electromotive mechanisms, medical equipment, also other advanced devices.
• Relatively small size with high pulling force – neodymium magnets offer high power in small dimensions, which enables their usage in miniature devices

Drawbacks and weaknesses of neodymium magnets: application proposals

• Brittleness is one of their disadvantages. Upon strong impact they can fracture. 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, as well as 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 recommend using waterproof magnets made of rubber, plastic or other material stable to moisture, in case of application outdoors
• Due to limitations in creating nuts and complex forms in magnets, we propose using cover - magnetic mount.
• Potential hazard resulting from small fragments of magnets pose a threat, in case of ingestion, which is particularly important in the context of child health protection. Furthermore, small components of these magnets are able to complicate diagnosis medical in case of swallowing.
• With budget limitations the cost of neodymium magnets is a challenge,

Detachment force of the magnet in optimal conditions – what affects it?

Breakaway force is the result of a measurement for optimal configuration, taking into account:

• on a base made of mild steel, optimally conducting the magnetic field
• possessing a massiveness of minimum 10 mm to avoid saturation
• characterized by even structure
• under conditions of gap-free contact (metal-to-metal)
• during pulling in a direction vertical to the plane
• in neutral thermal conditions

Magnet lifting force in use – key factors

Real force impacted by specific conditions, including (from most important):

• Clearance – the presence of any layer (rust, dirt, air) interrupts the magnetic circuit, which lowers power rapidly (even by 50% at 0.5 mm).
• Force direction – remember that the magnet has greatest strength perpendicularly. Under sliding down, the capacity drops drastically, often to levels of 20-30% of the maximum value.
• Plate thickness – too thin steel does not close the flux, causing part of the power to be lost to the other side.
• Chemical composition of the base – low-carbon steel attracts best. Alloy admixtures lower magnetic properties and lifting capacity.
• Surface structure – the more even the plate, the larger the contact zone and higher the lifting capacity. Roughness creates an air distance.
• Heat – NdFeB sinters have a negative temperature coefficient. When it is hot they are weaker, and in frost they can be stronger (up to a certain limit).

* Holding force was checked on the plate surface of 20 mm thickness, when the force acted perpendicularly, in contrast under shearing force the lifting capacity is smaller. Additionally, even a small distance {between} the magnet and the plate lowers the lifting capacity.