SM 32x425 [2xM8] / N42 - magnetic separator

Pros and cons of neodymium magnets.

Besides their exceptional magnetic power, neodymium magnets offer the following advantages:

• They have unchanged lifting capacity, and over around 10 years their performance decreases symbolically – ~1% (according to theory),
• They maintain their magnetic properties even under external field action,
• The use of an aesthetic layer of noble metals (nickel, gold, silver) causes the element to look better,
• They show high magnetic induction at the operating surface, which improves attraction properties,
• Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and are able to act (depending on the shape) even at a temperature of 230°C or more...
• Thanks to flexibility in forming and the capacity to adapt to individual projects,
• Fundamental importance in innovative solutions – they are utilized in hard drives, electric drive systems, medical equipment, also multitasking production systems.
• Thanks to concentrated force, small magnets offer high operating force, with minimal size,

Characteristics of disadvantages of neodymium magnets and ways of using them

• To avoid cracks upon strong impacts, we recommend using special steel housings. Such a solution protects the magnet and simultaneously increases its durability.
• When exposed to high temperature, neodymium magnets suffer a drop in strength. Often, when the temperature exceeds 80°C, their strength 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
• When exposed to humidity, magnets start to rust. To use them in conditions outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which prevent oxidation and corrosion.
• Limited possibility of making nuts in the magnet and complex forms - preferred is a housing - magnet mounting.
• Health risk resulting from small fragments of magnets can be dangerous, when accidentally swallowed, which is particularly important in the context of child health protection. Furthermore, tiny parts of these magnets can complicate diagnosis medical after entering the body.
• With large orders the cost of neodymium magnets is economically unviable,

Highest magnetic holding force – what affects it?

Information about lifting capacity was defined for optimal configuration, taking into account:

• with the use of a yoke made of low-carbon steel, guaranteeing maximum field concentration
• whose transverse dimension equals approx. 10 mm
• with an ideally smooth contact surface
• under conditions of no distance (surface-to-surface)
• for force acting at a right angle (in the magnet axis)
• at temperature approx. 20 degrees Celsius

Lifting capacity in real conditions – factors

Real force is influenced by working environment parameters, such as (from priority):

• Air gap (betwixt the magnet and the plate), because even a microscopic distance (e.g. 0.5 mm) can cause a reduction in lifting capacity by up to 50% (this also applies to varnish, corrosion or debris).
• Angle of force application – highest force is obtained only during pulling at a 90° angle. The resistance to sliding of the magnet along the plate is typically several times lower (approx. 1/5 of the lifting capacity).
• Element thickness – to utilize 100% power, the steel must be adequately massive. Thin sheet restricts the attraction force (the magnet "punches through" it).
• Material composition – different alloys attracts identically. Alloy additives worsen the interaction with the magnet.
• Surface structure – the more even the plate, the larger the contact zone and stronger the hold. Roughness creates an air distance.
• Thermal factor – hot environment reduces magnetic field. Too high temperature can permanently demagnetize the magnet.

* Lifting capacity testing was carried out on plates with a smooth surface of suitable thickness, under a perpendicular pulling force, however under shearing force the lifting capacity is smaller. Additionally, even a slight gap {between} the magnet and the plate reduces the load capacity.