SM 32x225 [2xM8] / N42 - magnetic separator

Advantages and disadvantages of rare earth magnets.

Besides their immense field intensity, neodymium magnets offer the following advantages:

• Their magnetic field is durable, and after approximately ten years it drops only by ~1% (according to research),
• They have excellent resistance to weakening of magnetic properties due to external fields,
• The use of an elegant layer of noble metals (nickel, gold, silver) causes the element to look better,
• The surface of neodymium magnets generates a concentrated magnetic field – this is a distinguishing feature,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their form) at temperatures up to 230°C and above...
• Thanks to the option of flexible forming and customization to unique solutions, magnetic components can be manufactured in a variety of forms and dimensions, which makes them more universal,
• Wide application in innovative solutions – they are used in magnetic memories, motor assemblies, diagnostic systems, as well as technologically advanced constructions.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• At strong impacts they can crack, therefore we advise placing them in strong housings. A metal housing provides additional protection against damage and increases the magnet's durability.
• Neodymium magnets lose their force under the influence of heating. As soon as 80°C is exceeded, many of them start losing their force. Therefore, we recommend our special magnets marked [AH], which maintain stability even at temperatures up to 230°C
• When exposed to humidity, magnets start to rust. To use them in conditions outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which secure oxidation as well as corrosion.
• Limited ability of making threads in the magnet and complex shapes - preferred is casing - magnet mounting.
• Possible danger to health – tiny shards of magnets can be dangerous, if swallowed, which gains importance in the aspect of protecting the youngest. Additionally, small elements of these devices are able to complicate diagnosis medical when they are in the body.
• Due to expensive raw materials, their price is relatively high,

Maximum lifting capacity of the magnet – what affects it?

Breakaway force was defined for ideal contact conditions, including:

• with the application of a sheet made of special test steel, guaranteeing full magnetic saturation
• with a thickness of at least 10 mm
• with an polished contact surface
• with zero gap (without paint)
• during detachment in a direction vertical to the mounting surface
• in temp. approx. 20°C

Key elements affecting lifting force

Bear in mind that the application force will differ depending on the following factors, in order of importance:

• Distance (between the magnet and the metal), because even a tiny clearance (e.g. 0.5 mm) can cause a reduction in lifting capacity by up to 50% (this also applies to paint, rust or debris).
• Force direction – declared lifting capacity refers to pulling vertically. When applying parallel force, the magnet holds much less (typically approx. 20-30% of nominal force).
• Steel thickness – insufficiently thick plate does not close the flux, causing part of the flux to be escaped into the air.
• Material composition – not every steel reacts the same. High carbon content weaken the interaction with the magnet.
• Surface condition – smooth surfaces ensure maximum contact, which improves force. Rough surfaces weaken the grip.
• Temperature influence – hot environment reduces magnetic field. Exceeding the limit temperature can permanently demagnetize the magnet.

* Lifting capacity was assessed using a smooth steel plate of suitable thickness (min. 20 mm), under vertically applied force, however under parallel forces the lifting capacity is smaller. In addition, even a small distance {between} the magnet and the plate lowers the load capacity.