SM 18x225 [2xM5] / N42 - magnetic separator

Strengths as well as weaknesses of rare earth magnets.

Besides their exceptional magnetic power, neodymium magnets offer the following advantages:

• Their magnetic field is maintained, and after around ten years it drops only by ~1% (theoretically),
• Magnets perfectly resist against loss of magnetization caused by ambient magnetic noise,
• A magnet with a smooth nickel surface looks better,
• Magnetic induction on the top side of the magnet turns out to be impressive,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their form) at temperatures up to 230°C and above...
• Thanks to flexibility in designing and the ability to modify to unusual requirements,
• Versatile presence in advanced technology sectors – they are commonly used in data components, electromotive mechanisms, advanced medical instruments, as well as other advanced devices.
• Thanks to concentrated force, small magnets offer high operating force, occupying minimum space,

Disadvantages of NdFeB magnets:

• Brittleness is one of their disadvantages. Upon intense impact they can break. We advise keeping them in a steel housing, which not only protects them against impacts but also increases their durability
• We warn that neodymium magnets can reduce their power at high temperatures. To prevent this, we recommend our specialized [AH] magnets, which work effectively even at 230°C.
• They oxidize in a humid environment - during use outdoors we recommend using waterproof magnets e.g. in rubber, plastic
• We suggest cover - magnetic mechanism, due to difficulties in realizing threads inside the magnet and complex forms.
• Potential hazard to health – tiny shards of magnets can be dangerous, when accidentally swallowed, which gains importance in the aspect of protecting the youngest. Additionally, small elements of these magnets can be problematic in diagnostics medical in case of swallowing.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Maximum magnetic pulling force – what affects it?

Information about lifting capacity is the result of a measurement for ideal contact conditions, taking into account:

• on a base made of structural steel, perfectly concentrating the magnetic field
• whose thickness is min. 10 mm
• with a surface perfectly flat
• with direct contact (without impurities)
• under perpendicular force vector (90-degree angle)
• in stable room temperature

Practical aspects of lifting capacity – factors

It is worth knowing that the magnet holding will differ subject to elements below, starting with the most relevant:

• Space between magnet and steel – every millimeter of separation (caused e.g. by veneer or unevenness) drastically reduces the pulling force, often by half at just 0.5 mm.
• Force direction – declared lifting capacity refers to pulling vertically. When attempting to slide, the magnet holds much less (often approx. 20-30% of nominal force).
• Base massiveness – too thin plate does not accept the full field, causing part of the power to be escaped into the air.
• Material composition – different alloys reacts the same. High carbon content weaken the interaction with the magnet.
• Surface structure – the smoother and more polished the surface, the larger the contact zone and higher the lifting capacity. Unevenness creates an air distance.
• Temperature – temperature increase results in weakening of force. Check the maximum operating temperature for a given model.

* Holding force was tested on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, whereas under parallel forces the holding force is lower. In addition, even a slight gap {between} the magnet and the plate decreases the load capacity.