SM 32x150 [2xM8] / N42 - magnetic separator

Strengths and weaknesses of neodymium magnets.

Besides their durability, neodymium magnets are valued for these benefits:

• They have constant strength, and over nearly ten years their attraction force decreases symbolically – ~1% (in testing),
• Neodymium magnets are characterized by extremely resistant to loss of magnetic properties caused by external magnetic fields,
• In other words, due to the aesthetic finish of gold, the element is aesthetically pleasing,
• Neodymium magnets ensure maximum magnetic induction on a small area, which ensures high operational effectiveness,
• Due to their durability and thermal resistance, neodymium magnets can operate (depending on the shape) even at high temperatures reaching 230°C or more...
• Possibility of detailed creating and adapting to complex requirements,
• Fundamental importance in high-tech industry – they find application in mass storage devices, motor assemblies, medical devices, also technologically advanced constructions.
• Thanks to concentrated force, small magnets offer high operating force, in miniature format,

Disadvantages of neodymium magnets:

• To avoid cracks upon strong impacts, we suggest using special steel housings. Such a solution secures the magnet and simultaneously improves its durability.
• Neodymium magnets lose power when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of power (a factor is the shape as well as dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are very resistant to heat
• When exposed to humidity, magnets start to rust. For applications outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which secure oxidation as well as corrosion.
• We suggest cover - magnetic mechanism, due to difficulties in creating nuts inside the magnet and complex forms.
• Health risk to health – tiny shards of magnets are risky, in case of ingestion, which is particularly important in the context of child health protection. Furthermore, tiny parts of these devices are able to be problematic in diagnostics medical after entering the body.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Maximum magnetic pulling force – what affects it?

The declared magnet strength refers to the maximum value, measured under laboratory conditions, meaning:

• using a plate made of mild steel, serving as a magnetic yoke
• with a thickness minimum 10 mm
• characterized by even structure
• under conditions of ideal adhesion (metal-to-metal)
• during detachment in a direction vertical to the mounting surface
• in stable room temperature

Practical lifting capacity: influencing factors

Real force is influenced by specific conditions, mainly (from most important):

• Clearance – the presence of any layer (rust, tape, air) acts as an insulator, which reduces power rapidly (even by 50% at 0.5 mm).
• Loading method – catalog parameter refers to detachment vertically. When applying parallel force, the magnet holds significantly lower power (typically approx. 20-30% of maximum force).
• Element thickness – to utilize 100% power, the steel must be sufficiently thick. Thin sheet restricts the lifting capacity (the magnet "punches through" it).
• Material type – ideal substrate is pure iron steel. Cast iron may generate lower lifting capacity.
• Surface quality – the smoother and more polished the surface, the larger the contact zone and stronger the hold. Roughness creates an air distance.
• Heat – NdFeB sinters have a negative temperature coefficient. At higher temperatures they are weaker, and in frost gain strength (up to a certain limit).

* Lifting capacity was determined by applying a polished steel plate of suitable thickness (min. 20 mm), under perpendicular pulling force, whereas under parallel forces the lifting capacity is smaller. In addition, even a minimal clearance {between} the magnet and the plate reduces the holding force.