SM 25x225 [2xM8] / N42 - magnetic separator

Pros as well as cons of rare earth magnets.

In addition to their pulling strength, neodymium magnets provide the following advantages:

• They have stable power, and over more than ten years their performance decreases symbolically – ~1% (in testing),
• They are extremely resistant to demagnetization induced by external field influence,
• Thanks to the glossy finish, the surface of nickel, gold-plated, or silver-plated gives an visually attractive appearance,
• Magnets have extremely high magnetic induction on the outer side,
• Through (appropriate) combination of ingredients, they can achieve high thermal resistance, enabling operation at temperatures reaching 230°C and above...
• Thanks to modularity in shaping and the capacity to customize to unusual requirements,
• Versatile presence in high-tech industry – they are utilized in magnetic memories, motor assemblies, diagnostic systems, also modern systems.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• Brittleness is one of their disadvantages. Upon strong impact they can fracture. We advise keeping them in a strong case, which not only secures them against impacts but also increases their durability
• We warn that neodymium magnets can lose 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 suggest using waterproof magnets e.g. in rubber, plastic
• Due to limitations in realizing threads and complicated forms in magnets, we recommend using cover - magnetic holder.
• Possible danger related to microscopic parts of magnets are risky, when accidentally swallowed, which gains importance in the context of child safety. Additionally, tiny parts of these products are able to disrupt the diagnostic process medical after entering the body.
• 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 contributes to it?

The declared magnet strength refers to the limit force, recorded under laboratory conditions, specifically:

• with the contact of a yoke made of low-carbon steel, ensuring maximum field concentration
• with a cross-section of at least 10 mm
• with an ideally smooth contact surface
• under conditions of no distance (metal-to-metal)
• during detachment in a direction perpendicular to the plane
• at standard ambient temperature

Magnet lifting force in use – key factors

Effective lifting capacity is affected by working environment parameters, such as (from priority):

• Distance – existence of any layer (paint, dirt, air) acts as an insulator, which lowers power rapidly (even by 50% at 0.5 mm).
• Force direction – remember that the magnet has greatest strength perpendicularly. Under shear forces, the capacity drops significantly, often to levels of 20-30% of the maximum value.
• Plate thickness – too thin sheet does not accept the full field, causing part of the power to be wasted into the air.
• Steel grade – ideal substrate is pure iron steel. Cast iron may have worse magnetic properties.
• Base smoothness – the smoother and more polished the surface, the better the adhesion and stronger the hold. Roughness acts like micro-gaps.
• Thermal factor – hot environment weakens magnetic field. Exceeding the limit temperature can permanently demagnetize the magnet.

* Lifting capacity testing was performed on a smooth plate of suitable thickness, under perpendicular forces, however under parallel forces the load capacity is reduced by as much as fivefold. In addition, even a slight gap {between} the magnet and the plate decreases the lifting capacity.