SM 25x375 [2xM8] / N52 - magnetic separator

Advantages and disadvantages of neodymium magnets.

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

• They retain magnetic properties for almost 10 years – the drop is just ~1% (in theory),
• They maintain their magnetic properties even under strong external field,
• A magnet with a smooth nickel surface has better aesthetics,
• The surface of neodymium magnets generates a maximum magnetic field – this is one of their assets,
• Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and are able to act (depending on the form) even at a temperature of 230°C or more...
• Thanks to flexibility in shaping and the capacity to adapt to client solutions,
• Key role in innovative solutions – they find application in magnetic memories, electric drive systems, medical devices, as well as modern systems.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Disadvantages of neodymium magnets:

• At very strong impacts they can crack, therefore we recommend placing them in special holders. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• Neodymium magnets lose strength when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of strength (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 extremely resistant to heat
• When exposed to humidity, magnets usually rust. To use them in conditions outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which prevent oxidation as well as corrosion.
• Due to limitations in realizing nuts and complex forms in magnets, we recommend using casing - magnetic mechanism.
• Health risk resulting from small fragments of magnets are risky, when accidentally swallowed, which gains importance in the context of child safety. Furthermore, small elements of these devices can disrupt the diagnostic process medical in case of swallowing.
• Due to neodymium price, their price is relatively high,

Highest magnetic holding force – what contributes to it?

The declared magnet strength concerns the maximum value, measured under ideal test conditions, specifically:

• using a plate made of mild steel, functioning as a ideal flux conductor
• possessing a thickness of at least 10 mm to ensure full flux closure
• with a plane free of scratches
• with zero gap (no paint)
• for force applied at a right angle (pull-off, not shear)
• in temp. approx. 20°C

Magnet lifting force in use – key factors

During everyday use, the actual lifting capacity results from a number of factors, presented from the most important:

• Space between surfaces – every millimeter of distance (caused e.g. by varnish or dirt) drastically reduces the pulling force, often by half at just 0.5 mm.
• Force direction – declared lifting capacity refers to pulling vertically. When applying parallel force, the magnet holds much less (often approx. 20-30% of maximum force).
• Steel thickness – insufficiently thick steel does not accept the full field, causing part of the power to be wasted into the air.
• Steel grade – the best choice is pure iron steel. Hardened steels may attract less.
• Surface condition – ground elements ensure maximum contact, which increases field saturation. Rough surfaces weaken the grip.
• Thermal environment – heating the magnet results in weakening of force. Check the maximum operating temperature for a given model.

* Lifting capacity was assessed using a smooth steel plate of optimal thickness (min. 20 mm), under perpendicular pulling force, in contrast under parallel forces the lifting capacity is smaller. Additionally, even a slight gap {between} the magnet and the plate lowers the holding force.