SM 32x200 [2xM8] / N52 - magnetic separator

Pros as well as cons of NdFeB magnets.

Apart from their superior magnetic energy, neodymium magnets have these key benefits:

• They retain attractive force for almost ten years – the loss is just ~1% (according to analyses),
• Magnets perfectly protect themselves against demagnetization caused by foreign field sources,
• Thanks to the metallic finish, the coating of nickel, gold-plated, or silver gives an elegant appearance,
• The surface of neodymium magnets generates a strong magnetic field – this is a key feature,
• Through (appropriate) combination of ingredients, they can achieve high thermal resistance, allowing for functioning at temperatures reaching 230°C and above...
• Thanks to freedom in forming and the capacity to adapt to specific needs,
• Universal use in future technologies – they serve a role in data components, brushless drives, advanced medical instruments, as well as complex engineering applications.
• Thanks to their power density, small magnets offer high operating force, occupying minimum space,

Disadvantages of NdFeB magnets:

• They are fragile upon heavy impacts. To avoid cracks, it is worth protecting magnets in a protective case. Such protection not only protects the magnet but also increases its resistance to damage
• Neodymium magnets lose force when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of power (a factor is the shape and 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
• Magnets exposed to a humid environment can corrode. Therefore while using outdoors, we recommend using water-impermeable magnets made of rubber, plastic or other material protecting against moisture
• We recommend a housing - magnetic holder, due to difficulties in creating nuts inside the magnet and complex shapes.
• Possible danger to health – tiny shards of magnets can be dangerous, when accidentally swallowed, which becomes key in the context of child safety. Furthermore, tiny parts of these devices can complicate diagnosis medical in case of swallowing.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Magnetic strength at its maximum – what it depends on?

Breakaway force was defined for the most favorable conditions, taking into account:

• on a base made of mild steel, optimally conducting the magnetic field
• whose transverse dimension equals approx. 10 mm
• characterized by even structure
• without any insulating layer between the magnet and steel
• during pulling in a direction perpendicular to the mounting surface
• at ambient temperature room level

Determinants of practical lifting force of a magnet

Holding efficiency impacted by working environment parameters, including (from priority):

• Clearance – existence of any layer (paint, dirt, gap) interrupts the magnetic circuit, which reduces power rapidly (even by 50% at 0.5 mm).
• Direction of force – highest force is available only during pulling at a 90° angle. The force required to slide of the magnet along the plate is standardly many times smaller (approx. 1/5 of the lifting capacity).
• Element thickness – to utilize 100% power, the steel must be sufficiently thick. Paper-thin metal limits the lifting capacity (the magnet "punches through" it).
• Steel grade – ideal substrate is pure iron steel. Stainless steels may generate lower lifting capacity.
• Surface condition – smooth surfaces ensure maximum contact, which improves field saturation. Uneven metal weaken the grip.
• Temperature – heating the magnet causes a temporary drop of induction. It is worth remembering the maximum operating temperature for a given model.

* Lifting capacity was measured with the use of a steel plate with a smooth surface of optimal thickness (min. 20 mm), under perpendicular detachment force, whereas under parallel forces the holding force is lower. Moreover, even a minimal clearance {between} the magnet’s surface and the plate decreases the load capacity.