SMZR 25x150 / N52 - magnetic separator with handle

Strengths and weaknesses of NdFeB magnets.

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

• They virtually do not lose strength, because even after 10 years the decline in efficiency is only ~1% (based on calculations),
• Magnets perfectly defend themselves against demagnetization caused by foreign field sources,
• A magnet with a shiny nickel surface has better aesthetics,
• Magnets have huge magnetic induction on the outer layer,
• Thanks to resistance to high temperature, they are able to function (depending on the shape) even at temperatures up to 230°C and higher...
• Possibility of custom creating as well as optimizing to specific applications,
• Universal use in advanced technology sectors – they are used in hard drives, motor assemblies, precision medical tools, also multitasking production systems.
• Relatively small size with high pulling force – neodymium magnets offer high power in compact dimensions, which makes them useful in miniature devices

Disadvantages of NdFeB magnets:

• To avoid cracks under impact, we suggest using special steel holders. Such a solution secures the magnet and simultaneously increases its durability.
• When exposed to high temperature, neodymium magnets suffer a drop in force. Often, when the temperature exceeds 80°C, their power decreases (depending on the size, as well as shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
• When exposed to humidity, magnets usually rust. To use them in conditions outside, it is recommended to use protective magnets, such as those in rubber or plastics, which prevent oxidation and corrosion.
• We suggest cover - magnetic mechanism, due to difficulties in producing nuts inside the magnet and complicated forms.
• Possible danger resulting from small fragments of magnets can be dangerous, if swallowed, which gains importance in the aspect of protecting the youngest. Additionally, tiny parts of these devices are able to be problematic in diagnostics medical after entering the body.
• With large orders the cost of neodymium magnets is a challenge,

Maximum lifting force for a neodymium magnet – what affects it?

The specified lifting capacity represents the maximum value, measured under optimal environment, meaning:

• using a base made of mild steel, serving as a circuit closing element
• with a thickness minimum 10 mm
• characterized by even structure
• under conditions of no distance (metal-to-metal)
• for force acting at a right angle (in the magnet axis)
• at temperature approx. 20 degrees Celsius

Magnet lifting force in use – key factors

During everyday use, the actual holding force is determined by many variables, listed from the most important:

• Gap (betwixt the magnet and the metal), because even a microscopic distance (e.g. 0.5 mm) results in a drastic drop in lifting capacity by up to 50% (this also applies to varnish, corrosion or dirt).
• Loading method – declared lifting capacity refers to pulling vertically. When attempting to slide, the magnet holds significantly lower power (often approx. 20-30% of maximum force).
• Base massiveness – too thin steel does not accept the full field, causing part of the power to be wasted to the other side.
• Material type – ideal substrate is high-permeability steel. Cast iron may have worse magnetic properties.
• Surface condition – ground elements guarantee perfect abutment, which increases force. Uneven metal weaken the grip.
• Thermal conditions – neodymium magnets have a negative temperature coefficient. At higher temperatures they lose power, and in frost they can be stronger (up to a certain limit).

* Lifting capacity testing was carried out on plates with a smooth surface of optimal thickness, under perpendicular forces, however under parallel forces the load capacity is reduced by as much as fivefold. Additionally, even a slight gap {between} the magnet and the plate reduces the lifting capacity.