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

Advantages and disadvantages of rare earth magnets.

Besides their tremendous strength, neodymium magnets offer the following advantages:

• They virtually do not lose power, because even after ten years the performance loss is only ~1% (according to literature),
• They are resistant to demagnetization induced by external magnetic fields,
• In other words, due to the metallic layer of gold, the element gains visual value,
• They show high magnetic induction at the operating surface, making them more effective,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their shape) at temperatures up to 230°C and above...
• Possibility of individual shaping and adapting to specific requirements,
• Key role in modern industrial fields – they are utilized in HDD drives, electric drive systems, diagnostic systems, and complex engineering applications.
• Compactness – despite small sizes they provide effective action, making them ideal for precision applications

Problematic aspects of neodymium magnets and proposals for their use:

• At strong impacts they can crack, therefore we advise placing them in strong housings. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• Neodymium magnets lose their power 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 durability even at temperatures up to 230°C
• They rust in a humid environment - during use outdoors we suggest using waterproof magnets e.g. in rubber, plastic
• Limited ability of creating nuts in the magnet and complex forms - preferred is casing - magnetic holder.
• Health risk to health – tiny shards of magnets are risky, when accidentally swallowed, which becomes key in the context of child safety. Furthermore, tiny parts of these devices are able to disrupt the diagnostic process medical when they are in the body.
• Due to neodymium price, their price exceeds standard values,

Optimal lifting capacity of a neodymium magnet – what it depends on?

The specified lifting capacity represents the limit force, obtained under laboratory conditions, meaning:

• using a plate made of high-permeability steel, acting as a circuit closing element
• possessing a thickness of minimum 10 mm to ensure full flux closure
• with an polished touching surface
• with zero gap (without paint)
• under perpendicular application of breakaway force (90-degree angle)
• at temperature room level

Determinants of lifting force in real conditions

Please note that the application force may be lower subject to the following factors, starting with the most relevant:

• Clearance – existence of any layer (paint, dirt, air) interrupts the magnetic circuit, which lowers power rapidly (even by 50% at 0.5 mm).
• Force direction – catalog parameter refers to detachment vertically. When attempting to slide, the magnet holds significantly lower power (often approx. 20-30% of maximum force).
• Element thickness – to utilize 100% power, the steel must be sufficiently thick. Paper-thin metal restricts the attraction force (the magnet "punches through" it).
• Steel grade – the best choice is pure iron steel. Hardened steels may have worse magnetic properties.
• Surface condition – smooth surfaces ensure maximum contact, which improves field saturation. Rough surfaces reduce efficiency.
• Temperature influence – hot environment weakens pulling force. Exceeding the limit temperature can permanently demagnetize the magnet.

* Lifting capacity was measured using a polished steel plate of suitable thickness (min. 20 mm), under perpendicular detachment force, in contrast under parallel forces the lifting capacity is smaller. In addition, even a minimal clearance {between} the magnet’s surface and the plate decreases the lifting capacity.