SM 18x300 [2xM5] / N42 - magnetic separator

Strengths as well as weaknesses of NdFeB magnets.

In addition to their pulling strength, neodymium magnets provide the following advantages:

• They retain magnetic properties for around ten years – the loss is just ~1% (in theory),
• Magnets perfectly protect themselves against demagnetization caused by foreign field sources,
• By covering with a decorative layer of gold, the element acquires an modern look,
• Magnetic induction on the working layer of the magnet is very high,
• Thanks to resistance to high temperature, they can operate (depending on the form) even at temperatures up to 230°C and higher...
• Thanks to versatility in shaping and the ability to customize to client solutions,
• Universal use in advanced technology sectors – they find application in data components, brushless drives, medical devices, as well as multitasking production systems.
• Compactness – despite small sizes they provide effective action, making them ideal for precision applications

Problematic aspects of neodymium magnets: weaknesses and usage proposals

• To avoid cracks under impact, we recommend using special steel holders. Such a solution protects the magnet and simultaneously improves its durability.
• When exposed to high temperature, neodymium magnets suffer a drop in force. 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
• They rust in a humid environment. For use outdoors we recommend using waterproof magnets e.g. in rubber, plastic
• We recommend cover - magnetic mount, due to difficulties in producing threads inside the magnet and complicated shapes.
• Potential hazard related to microscopic parts of magnets can be dangerous, if swallowed, which gains importance in the context of child health protection. Additionally, tiny parts of these devices can disrupt the diagnostic process medical when they are in the body.
• With budget limitations the cost of neodymium magnets can be a barrier,

Magnetic strength at its maximum – what contributes to it?

The force parameter is a result of laboratory testing executed under the following configuration:

• using a sheet made of high-permeability steel, acting as a magnetic yoke
• whose thickness equals approx. 10 mm
• with a surface perfectly flat
• without the slightest air gap between the magnet and steel
• for force applied at a right angle (pull-off, not shear)
• at temperature room level

What influences lifting capacity in practice

Holding efficiency impacted by specific conditions, such as (from most important):

• Gap between magnet and steel – even a fraction of a millimeter of separation (caused e.g. by veneer or unevenness) significantly weakens the magnet efficiency, often by half at just 0.5 mm.
• Force direction – remember that the magnet has greatest strength perpendicularly. Under sliding down, the holding force drops drastically, often to levels of 20-30% of the nominal value.
• Base massiveness – insufficiently thick steel does not accept the full field, causing part of the power to be lost into the air.
• Material composition – different alloys reacts the same. High carbon content worsen the interaction with the magnet.
• Plate texture – smooth surfaces ensure maximum contact, which increases force. Uneven metal weaken the grip.
• Temperature influence – high temperature reduces magnetic field. Exceeding the limit temperature can permanently damage the magnet.

* Holding force was tested on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, whereas under attempts to slide the magnet the lifting capacity is smaller. Moreover, even a slight gap {between} the magnet and the plate lowers the load capacity.