SM 32x375 [2xM8] / N42 - magnetic separator

Advantages and disadvantages of rare earth magnets.

In addition to their magnetic efficiency, neodymium magnets provide the following advantages:

• They virtually do not lose strength, because even after 10 years the performance loss is only ~1% (in laboratory conditions),
• They do not lose their magnetic properties even under external field action,
• A magnet with a smooth nickel surface looks better,
• They feature high magnetic induction at the operating surface, which improves attraction properties,
• Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the shape) even at high temperatures reaching 230°C or more...
• Possibility of exact forming as well as optimizing to individual conditions,
• Versatile presence in modern industrial fields – they are utilized in mass storage devices, electromotive mechanisms, medical devices, and 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 too strong impacts. To avoid cracks, it is worth protecting magnets using a steel holder. Such protection not only protects the magnet but also increases its resistance to damage
• When exposed to high temperature, neodymium magnets suffer a drop in power. 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 recommend using waterproof magnets made of rubber, plastic or other material stable to moisture, when using outdoors
• Due to limitations in producing nuts and complicated forms in magnets, we propose using casing - magnetic holder.
• Possible danger related to microscopic parts of magnets can be dangerous, when accidentally swallowed, which is particularly important in the aspect of protecting the youngest. Furthermore, tiny parts of these products can be problematic in diagnostics medical after entering the body.
• Due to neodymium price, their price exceeds standard values,

Highest magnetic holding force – what it depends on?

Breakaway force was defined for ideal contact conditions, including:

• using a base made of high-permeability steel, acting as a ideal flux conductor
• whose transverse dimension equals approx. 10 mm
• with an ideally smooth contact surface
• without any insulating layer between the magnet and steel
• under perpendicular force direction (90-degree angle)
• in stable room temperature

What influences lifting capacity in practice

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

• Gap between surfaces – every millimeter of separation (caused e.g. by veneer or unevenness) diminishes the magnet efficiency, often by half at just 0.5 mm.
• Load vector – maximum parameter is available only during perpendicular pulling. The resistance to sliding of the magnet along the surface is typically several times smaller (approx. 1/5 of the lifting capacity).
• Wall thickness – thin material does not allow full use of the magnet. Part of the magnetic field penetrates through instead of generating force.
• Steel grade – the best choice is high-permeability steel. Cast iron may attract less.
• Surface structure – the smoother and more polished the surface, the larger the contact zone and higher the lifting capacity. Unevenness creates an air distance.
• Thermal environment – heating the magnet causes a temporary drop of induction. Check the thermal limit for a given model.

* Lifting capacity was assessed with the use of a polished steel plate of suitable thickness (min. 20 mm), under perpendicular pulling force, in contrast under shearing force the lifting capacity is smaller. Moreover, even a minimal clearance {between} the magnet and the plate decreases the load capacity.