SM 18x275 [2xM5] / N42 - magnetic separator

Pros and cons of rare earth magnets.

Apart from their strong holding force, neodymium magnets have these key benefits:

• They have unchanged lifting capacity, and over nearly ten years their performance decreases symbolically – ~1% (in testing),
• They feature excellent resistance to magnetic field loss due to opposing magnetic fields,
• The use of an elegant layer of noble metals (nickel, gold, silver) causes the element to have aesthetics,
• Magnets have very high magnetic induction on the outer layer,
• Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and can work (depending on the form) even at a temperature of 230°C or more...
• Thanks to modularity in forming and the ability to adapt to complex applications,
• Significant place in high-tech industry – they are commonly used in data components, electric drive systems, precision medical tools, as well as complex engineering applications.
• Compactness – despite small sizes they provide effective action, making them ideal for precision applications

Disadvantages of neodymium magnets:

• They are fragile upon heavy impacts. To avoid cracks, it is worth securing magnets in special housings. Such protection not only protects the magnet but also increases its resistance to damage
• When exposed to high temperature, neodymium magnets experience a drop in force. Often, when the temperature exceeds 80°C, their strength decreases (depending on the size, as well as 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 advise using waterproof magnets made of rubber, plastic or other material resistant to moisture, in case of application outdoors
• Due to limitations in creating threads and complicated shapes in magnets, we recommend using a housing - magnetic holder.
• Health risk related to microscopic parts of magnets pose a threat, in case of ingestion, which becomes key in the aspect of protecting the youngest. It is also worth noting that small elements of these devices can complicate diagnosis medical in case of swallowing.
• Due to neodymium price, their price is relatively high,

Optimal lifting capacity of a neodymium magnet – what affects it?

The declared magnet strength represents the peak performance, recorded under laboratory conditions, namely:

• with the application of a yoke made of low-carbon steel, guaranteeing full magnetic saturation
• whose thickness equals approx. 10 mm
• with an ideally smooth contact surface
• with direct contact (no paint)
• for force acting at a right angle (pull-off, not shear)
• at temperature room level

Magnet lifting force in use – key factors

Bear in mind that the working load may be lower influenced by the following factors, in order of importance:

• Distance – existence of foreign body (rust, tape, gap) interrupts the magnetic circuit, which reduces capacity rapidly (even by 50% at 0.5 mm).
• Force direction – remember that the magnet has greatest strength perpendicularly. Under shear forces, the capacity drops drastically, often to levels of 20-30% of the maximum value.
• Metal thickness – the thinner the sheet, the weaker the hold. Part of the magnetic field passes through the material instead of converting into lifting capacity.
• Steel grade – the best choice is pure iron steel. Stainless steels may have worse magnetic properties.
• Surface condition – ground elements guarantee perfect abutment, which improves force. Rough surfaces reduce efficiency.
• Operating temperature – NdFeB sinters have a sensitivity to temperature. At higher temperatures they are weaker, and in frost they can be stronger (up to a certain limit).

* Lifting capacity testing was carried out on a smooth plate of optimal thickness, under perpendicular forces, whereas under attempts to slide the magnet the holding force is lower. Additionally, even a small distance {between} the magnet and the plate decreases the load capacity.