SMZR 32x125 / N52 - magnetic separator with handle

Pros as well as cons of rare earth magnets.

Apart from their notable magnetism, neodymium magnets have these key benefits:

• They have stable power, and over nearly ten years their performance decreases symbolically – ~1% (according to theory),
• Magnets very well protect themselves against demagnetization caused by ambient magnetic noise,
• In other words, due to the shiny layer of nickel, the element is aesthetically pleasing,
• Neodymium magnets ensure maximum magnetic induction on a small surface, which ensures high operational effectiveness,
• 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...
• Due to the potential of accurate molding and customization to specialized needs, neodymium magnets can be modeled in a broad palette of forms and dimensions, which amplifies use scope,
• Significant place in high-tech industry – they find application in HDD drives, electromotive mechanisms, medical devices, as well as other advanced devices.
• Thanks to efficiency per cm³, small magnets offer high operating force, occupying minimum space,

What to avoid - cons of neodymium magnets: application proposals

• Brittleness is one of their disadvantages. Upon strong impact they can break. We recommend keeping them in a steel housing, which not only protects them against impacts but also raises their 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 recommend using waterproof magnets made of rubber, plastic or other material stable to moisture, when using outdoors
• Due to limitations in creating threads and complicated shapes in magnets, we propose using cover - magnetic holder.
• Potential hazard related to microscopic parts of magnets pose a threat, in case of ingestion, which becomes key in the context of child health protection. It is also worth noting that small components of these magnets are able to be problematic in diagnostics medical in case of swallowing.
• High unit price – neodymium magnets have a higher price than other types of magnets (e.g. ferrite), which increases costs of application in large quantities

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

The lifting capacity listed is a theoretical maximum value conducted under the following configuration:

• with the contact of a yoke made of special test steel, ensuring full magnetic saturation
• with a thickness minimum 10 mm
• with a plane perfectly flat
• without any insulating layer between the magnet and steel
• under axial force vector (90-degree angle)
• at standard ambient temperature

Lifting capacity in real conditions – factors

During everyday use, the real power is determined by many variables, presented from the most important:

• Distance (between the magnet and the plate), since even a very small distance (e.g. 0.5 mm) leads to a reduction in force by up to 50% (this also applies to varnish, corrosion or debris).
• Pull-off angle – note that the magnet holds strongest perpendicularly. Under sliding down, the capacity drops drastically, often to levels of 20-30% of the nominal value.
• Substrate thickness – to utilize 100% power, the steel must be adequately massive. Paper-thin metal restricts the lifting capacity (the magnet "punches through" it).
• Steel grade – the best choice is high-permeability steel. Cast iron may attract less.
• Surface quality – the more even the surface, the better the adhesion and higher the lifting capacity. Unevenness acts like micro-gaps.
• Thermal environment – temperature increase causes a temporary drop of force. Check the maximum operating temperature for a given model.

* Lifting capacity testing was carried out on plates with a smooth surface of optimal thickness, under perpendicular forces, however under attempts to slide the magnet the load capacity is reduced by as much as 5 times. Additionally, even a small distance {between} the magnet’s surface and the plate lowers the load capacity.