SM 32x200 [2xM8] / N42 - magnetic separator

Advantages and disadvantages of NdFeB magnets.

In addition to their magnetic efficiency, neodymium magnets provide the following advantages:

• They have stable power, and over around ten years their performance decreases symbolically – ~1% (in testing),
• They possess excellent resistance to magnetic field loss as a result of external fields,
• In other words, due to the shiny layer of silver, the element becomes visually attractive,
• Magnetic induction on the top side of the magnet turns out to be impressive,
• Thanks to resistance to high temperature, they are capable of working (depending on the shape) even at temperatures up to 230°C and higher...
• Thanks to freedom in designing and the capacity to modify to complex applications,
• Universal use in modern technologies – they find application in hard drives, brushless drives, medical equipment, as well as industrial machines.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

What to avoid - cons of neodymium magnets: application proposals

• They are fragile upon heavy impacts. To avoid cracks, it is worth securing magnets using a steel holder. Such protection not only protects the magnet but also improves its resistance to damage
• Neodymium magnets lose force when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop 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 extremely resistant to heat
• Due to the susceptibility of magnets to corrosion in a humid environment, we recommend using waterproof magnets made of rubber, plastic or other material immune to moisture, in case of application outdoors
• Due to limitations in creating nuts and complicated shapes in magnets, we propose using casing - magnetic mount.
• Potential hazard related to microscopic parts of magnets can be dangerous, in case of ingestion, which gains importance in the context of child health protection. Furthermore, small components of these devices can disrupt the diagnostic process medical in case of swallowing.
• With large orders the cost of neodymium magnets is economically unviable,

Best holding force of the magnet in ideal parameters – what affects it?

Breakaway force was defined for optimal configuration, including:

• on a block made of mild steel, perfectly concentrating the magnetic field
• possessing a thickness of minimum 10 mm to avoid saturation
• with a surface cleaned and smooth
• with direct contact (no coatings)
• during detachment in a direction perpendicular to the plane
• at temperature room level

Impact of factors on magnetic holding capacity in practice

Please note that the working load may be lower influenced by the following factors, starting with the most relevant:

• Distance – existence of foreign body (paint, dirt, gap) acts as an insulator, which reduces power steeply (even by 50% at 0.5 mm).
• Load vector – highest force is reached only during perpendicular pulling. The resistance to sliding of the magnet along the surface is standardly several times smaller (approx. 1/5 of the lifting capacity).
• Wall thickness – the thinner the sheet, the weaker the hold. Part of the magnetic field penetrates through instead of converting into lifting capacity.
• Metal type – not every steel attracts identically. High carbon content worsen the interaction with the magnet.
• Plate texture – ground elements guarantee perfect abutment, which improves force. Rough surfaces reduce efficiency.
• Temperature influence – high temperature weakens pulling force. Too high temperature can permanently damage the magnet.

* Lifting capacity testing was conducted on plates with a smooth surface of optimal thickness, under perpendicular forces, however under shearing force the lifting capacity is smaller. Moreover, even a small distance {between} the magnet and the plate decreases the holding force.