SM 18x100 [2xM5] / N42 - magnetic separator

Pros and cons of neodymium magnets.

In addition to their long-term stability, neodymium magnets provide the following advantages:

• Their strength is maintained, and after approximately 10 years it decreases only by ~1% (according to research),
• Neodymium magnets remain remarkably resistant to demagnetization caused by external magnetic fields,
• Thanks to the shiny finish, the layer of Ni-Cu-Ni, gold, or silver-plated gives an modern appearance,
• Magnetic induction on the top side of the magnet is strong,
• Due to their enhanced temperature resistance, they can operate (depending on the geometry) even at temperatures up to 230°C or more,
• Thanks to the ability of flexible forming and customization to custom needs, neodymium magnets can be manufactured in a wide range of shapes and sizes, which increases their versatility,
• Wide application in high-tech industry – they are commonly used in computer drives, electric motors, advanced medical instruments, also technologically advanced constructions.
• Thanks to concentrated force, small magnets offer high operating force, in miniature format,

Disadvantages of NdFeB magnets:

• They are prone to damage upon heavy impacts. To avoid cracks, it is worth securing magnets in a protective case. Such protection not only protects the magnet but also increases its resistance to damage
• When exposed to high temperature, neodymium magnets suffer a drop in power. Often, when the temperature exceeds 80°C, their power decreases (depending on the size and shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
• 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 resistant to moisture
• Limited ability of producing threads in the magnet and complex forms - preferred is cover - magnetic holder.
• Potential hazard resulting from small fragments of magnets can be dangerous, if swallowed, which gains importance in the context of child health protection. Furthermore, tiny parts of these products are able to complicate diagnosis medical when they are in the body.
• With large orders the cost of neodymium magnets can be a barrier,

Breakaway strength of the magnet in ideal conditions – what contributes to it?

Information about lifting capacity was defined for ideal contact conditions, including:

• using a sheet made of mild steel, serving as a ideal flux conductor
• whose thickness equals approx. 10 mm
• characterized by even structure
• without the slightest insulating layer between the magnet and steel
• for force applied at a right angle (pull-off, not shear)
• at ambient temperature room level

Practical aspects of lifting capacity – factors

Please note that the application force will differ subject to elements below, starting with the most relevant:

• Clearance – the presence of any layer (rust, tape, air) interrupts the magnetic circuit, which reduces power steeply (even by 50% at 0.5 mm).
• Force direction – remember that the magnet has greatest strength perpendicularly. Under shear forces, the holding force drops significantly, often to levels of 20-30% of the nominal value.
• Substrate thickness – for full efficiency, the steel must be adequately massive. Thin sheet restricts the lifting capacity (the magnet "punches through" it).
• Steel type – mild steel attracts best. Alloy steels reduce magnetic permeability and holding force.
• Surface condition – smooth surfaces guarantee perfect abutment, which increases force. Uneven metal reduce efficiency.
• Temperature influence – high temperature weakens magnetic field. Exceeding the limit temperature can permanently damage the magnet.

* Holding force was measured on the plate surface of 20 mm thickness, when the force acted perpendicularly, in contrast under attempts to slide the magnet the holding force is lower. Moreover, even a small distance {between} the magnet and the plate reduces the holding force.