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

Pros as well as cons of rare earth magnets.

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

• They virtually do not lose power, because even after 10 years the decline in efficiency is only ~1% (in laboratory conditions),
• Neodymium magnets are characterized by highly resistant to demagnetization caused by external magnetic fields,
• Thanks to the metallic finish, the surface of nickel, gold, or silver-plated gives an modern appearance,
• They are known for high magnetic induction at the operating surface, which increases their power,
• Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the form) even at high temperatures reaching 230°C or more...
• Thanks to versatility in designing and the capacity to modify to unusual requirements,
• Wide application in high-tech industry – they are utilized in mass storage devices, electric motors, diagnostic systems, also industrial machines.
• Thanks to efficiency per cm³, small magnets offer high operating force, in miniature format,

Characteristics of disadvantages of neodymium magnets: weaknesses and usage proposals

• They are prone to damage upon heavy impacts. To avoid cracks, it is worth protecting magnets in a protective case. Such protection not only shields the magnet but also improves its resistance to damage
• We warn that neodymium magnets can reduce their strength at high temperatures. To prevent this, we recommend our specialized [AH] magnets, which work effectively even at 230°C.
• Magnets exposed to a humid environment can corrode. Therefore while using outdoors, we advise using waterproof magnets made of rubber, plastic or other material resistant to moisture
• Due to limitations in realizing nuts and complex forms in magnets, we propose using a housing - magnetic holder.
• Potential hazard resulting from small fragments of magnets are risky, when accidentally swallowed, which gains importance in the aspect of protecting the youngest. Additionally, small elements of these products are able to be problematic in diagnostics medical in case of swallowing.
• With budget limitations the cost of neodymium magnets can be a barrier,

Detachment force of the magnet in optimal conditions – what contributes to it?

Holding force of 0 kg is a measurement result conducted under the following configuration:

• on a plate made of mild steel, optimally conducting the magnetic flux
• with a thickness of at least 10 mm
• characterized by even structure
• with zero gap (without impurities)
• under perpendicular force vector (90-degree angle)
• at room temperature

Practical lifting capacity: influencing factors

Real force impacted by working environment parameters, including (from priority):

• Gap between surfaces – every millimeter of separation (caused e.g. by varnish or unevenness) diminishes the pulling force, often by half at just 0.5 mm.
• Load vector – maximum parameter is reached only during pulling at a 90° angle. The force required to slide of the magnet along the surface is usually several times smaller (approx. 1/5 of the lifting capacity).
• Base massiveness – insufficiently thick steel causes magnetic saturation, causing part of the flux to be wasted into the air.
• Steel grade – the best choice is high-permeability steel. Hardened steels may generate lower lifting capacity.
• Surface condition – ground elements ensure maximum contact, which improves field saturation. Uneven metal weaken the grip.
• Temperature influence – high temperature reduces magnetic field. Too high temperature can permanently damage the magnet.

* Lifting capacity testing was performed on plates with a smooth surface of optimal thickness, under perpendicular forces, in contrast under shearing force the lifting capacity is smaller. In addition, even a minimal clearance {between} the magnet’s surface and the plate decreases the holding force.