SM 25x250 [2xM8] / N52 - magnetic separator

Advantages as well as disadvantages of NdFeB 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% (in laboratory conditions),
• They do not lose their magnetic properties even under close interference source,
• By applying a smooth coating of silver, the element has an aesthetic look,
• The surface of neodymium magnets generates a concentrated magnetic field – this is one of their assets,
• Through (adequate) combination of ingredients, they can achieve high thermal strength, allowing for operation at temperatures approaching 230°C and above...
• In view of the possibility of accurate molding and adaptation to unique projects, neodymium magnets can be modeled in a variety of forms and dimensions, which expands the range of possible applications,
• Significant place in innovative solutions – they find application in mass storage devices, drive modules, diagnostic systems, also modern systems.
• Thanks to efficiency per cm³, small magnets offer high operating force, in miniature format,

Disadvantages of NdFeB magnets:

• To avoid cracks upon strong impacts, we suggest using special steel housings. Such a solution secures the magnet and simultaneously improves its durability.
• Neodymium magnets demagnetize 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 very resistant to heat
• They rust in a humid environment - during use outdoors we recommend using waterproof magnets e.g. in rubber, plastic
• Limited ability of making nuts in the magnet and complex forms - recommended is cover - mounting mechanism.
• Potential hazard to health – tiny shards of magnets can be dangerous, in case of ingestion, which is particularly important in the aspect of protecting the youngest. Furthermore, small elements of these devices can disrupt the diagnostic process medical when they are in the body.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Best holding force of the magnet in ideal parameters – what contributes to it?

Information about lifting capacity was defined for the most favorable conditions, taking into account:

• with the use of a yoke made of low-carbon steel, guaranteeing full magnetic saturation
• whose transverse dimension is min. 10 mm
• with an ground contact surface
• with zero gap (without paint)
• during detachment in a direction perpendicular to the mounting surface
• at temperature approx. 20 degrees Celsius

Determinants of lifting force in real conditions

Real force is influenced by working environment parameters, mainly (from priority):

• Air gap (between the magnet and the plate), as even a very small distance (e.g. 0.5 mm) leads to a drastic drop in lifting capacity by up to 50% (this also applies to varnish, rust or debris).
• Angle of force application – highest force is obtained only during perpendicular pulling. The force required to slide of the magnet along the plate is typically several times lower (approx. 1/5 of the lifting capacity).
• Base massiveness – insufficiently thick steel causes magnetic saturation, causing part of the flux to be escaped into the air.
• Material type – the best choice is pure iron steel. Hardened steels may attract less.
• Surface quality – the smoother and more polished the plate, the larger the contact zone and higher the lifting capacity. Unevenness acts like micro-gaps.
• Thermal environment – temperature increase causes a temporary drop of force. Check the thermal limit for a given model.

* Lifting capacity was determined by applying a smooth steel plate of suitable thickness (min. 20 mm), under perpendicular detachment force, in contrast under attempts to slide the magnet the holding force is lower. In addition, even a small distance {between} the magnet and the plate lowers the holding force.