SM 32x250 [2xM8] / N52 - magnetic separator

Strengths and weaknesses of rare earth magnets.

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

• They virtually do not lose power, because even after ten years the performance loss is only ~1% (according to literature),
• They retain their magnetic properties even under strong external field,
• By applying a reflective layer of nickel, the element has an modern look,
• Magnets exhibit huge magnetic induction on the working surface,
• Due to their durability and thermal resistance, neodymium magnets can operate (depending on the form) even at high temperatures reaching 230°C or more...
• Thanks to modularity in forming and the ability to customize to unusual requirements,
• Huge importance in innovative solutions – they find application in HDD drives, electromotive mechanisms, precision medical tools, also industrial machines.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Drawbacks and weaknesses of neodymium magnets: tips and applications.

• To avoid cracks under impact, we recommend using special steel housings. Such a solution secures the magnet and simultaneously improves its durability.
• When exposed to high temperature, neodymium magnets experience a drop in strength. Often, when the temperature exceeds 80°C, their power decreases (depending on the size and shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
• Due to the susceptibility of magnets to corrosion in a humid environment, we suggest using waterproof magnets made of rubber, plastic or other material stable to moisture, in case of application outdoors
• We suggest cover - magnetic holder, due to difficulties in realizing threads inside the magnet and complex shapes.
• Health risk to health – tiny shards of magnets pose a threat, in case of ingestion, which gains importance in the context of child health protection. Additionally, tiny parts of these products are able to complicate diagnosis medical in case of swallowing.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Detachment force of the magnet in optimal conditions – what it depends on?

Breakaway force is the result of a measurement for ideal contact conditions, including:

• with the contact of a sheet made of low-carbon steel, ensuring maximum field concentration
• possessing a massiveness of minimum 10 mm to avoid saturation
• with a surface cleaned and smooth
• under conditions of no distance (surface-to-surface)
• under vertical force direction (90-degree angle)
• in neutral thermal conditions

Determinants of practical lifting force of a magnet

Bear in mind that the magnet holding will differ influenced by elements below, starting with the most relevant:

• Gap (between the magnet and the metal), because even a very small distance (e.g. 0.5 mm) leads to a reduction in force by up to 50% (this also applies to paint, corrosion or debris).
• Angle of force application – highest force is available only during pulling at a 90° angle. The shear force of the magnet along the plate is usually several times lower (approx. 1/5 of the lifting capacity).
• Plate thickness – insufficiently thick steel does not accept the full field, causing part of the power to be escaped into the air.
• Metal type – different alloys reacts the same. High carbon content weaken the interaction with the magnet.
• Surface quality – the smoother and more polished the surface, the larger the contact zone and higher the lifting capacity. Unevenness acts like micro-gaps.
• Temperature – temperature increase causes a temporary drop of induction. Check the thermal limit for a given model.

* Holding force was measured on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, in contrast under parallel forces the load capacity is reduced by as much as 5 times. Moreover, even a minimal clearance {between} the magnet’s surface and the plate lowers the holding force.