SM 32x325 [2xM8] / N42 - magnetic separator

Pros and cons of rare earth magnets.

Besides their remarkable strength, neodymium magnets offer the following advantages:

• They have stable power, and over around ten years their performance decreases symbolically – ~1% (according to theory),
• They are resistant to demagnetization induced by external field influence,
• A magnet with a metallic nickel surface is more attractive,
• They show high magnetic induction at the operating surface, which improves attraction properties,
• Through (adequate) combination of ingredients, they can achieve high thermal strength, enabling operation at temperatures reaching 230°C and above...
• Thanks to flexibility in constructing and the ability to customize to individual projects,
• Wide application in future technologies – they are commonly used in mass storage devices, brushless drives, medical equipment, as well as technologically advanced constructions.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Disadvantages of neodymium magnets:

• Brittleness is one of their disadvantages. Upon strong impact they can fracture. We recommend keeping them in a strong case, which not only protects them against impacts but also increases their durability
• We warn that neodymium magnets can lose their power at high temperatures. To prevent this, we advise our specialized [AH] magnets, which work effectively even at 230°C.
• They rust in a humid environment. For use outdoors we suggest using waterproof magnets e.g. in rubber, plastic
• Due to limitations in creating threads and complex forms in magnets, we recommend using a housing - magnetic mechanism.
• Health risk related to microscopic parts of magnets pose a threat, when accidentally swallowed, which is particularly important in the aspect of protecting the youngest. Additionally, small components of these devices are able to disrupt the diagnostic process medical when they are in the body.
• With mass production the cost of neodymium magnets is a challenge,

Breakaway strength of the magnet in ideal conditions – what contributes to it?

The force parameter is a measurement result conducted under specific, ideal conditions:

• using a base made of mild steel, serving as a ideal flux conductor
• with a cross-section no less than 10 mm
• with a plane cleaned and smooth
• with total lack of distance (no coatings)
• during pulling in a direction perpendicular to the plane
• in stable room temperature

Impact of factors on magnetic holding capacity in practice

Real force is influenced by specific conditions, such as (from most important):

• Space between magnet and steel – even a fraction of a millimeter of distance (caused e.g. by varnish or unevenness) significantly weakens the magnet efficiency, often by half at just 0.5 mm.
• Force direction – catalog parameter refers to pulling vertically. When attempting to slide, the magnet holds significantly lower power (often approx. 20-30% of maximum force).
• Plate thickness – too thin sheet does not close the flux, causing part of the power to be escaped to the other side.
• Steel grade – ideal substrate is high-permeability steel. Cast iron may have worse magnetic properties.
• Surface quality – the more even the plate, the better the adhesion and stronger the hold. Unevenness creates an air distance.
• Temperature – heating the magnet causes a temporary drop of induction. It is worth remembering the thermal limit for a given model.

* Lifting capacity was measured using a steel plate with a smooth surface of optimal thickness (min. 20 mm), under perpendicular detachment force, in contrast under attempts to slide the magnet the load capacity is reduced by as much as fivefold. Additionally, even a minimal clearance {between} the magnet and the plate reduces the lifting capacity.