MP 30x6x10 / N38 - ring magnet

Pros as well as cons of rare earth magnets.

In addition to their long-term stability, neodymium magnets provide the following advantages:

• They virtually do not lose strength, because even after 10 years the performance loss is only ~1% (based on calculations),
• Neodymium magnets are distinguished by remarkably resistant to demagnetization caused by external field sources,
• Thanks to the metallic finish, the plating of nickel, gold-plated, or silver gives an clean appearance,
• They show 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 detailed shaping and modifying to concrete applications,
• Versatile presence in innovative solutions – they serve a role in magnetic memories, electric drive systems, diagnostic systems, also modern systems.
• Thanks to their power density, small magnets offer high operating force, occupying minimum space,

What to avoid - cons of neodymium magnets: application proposals

• They are prone to damage upon too strong impacts. To avoid cracks, it is worth securing magnets in a protective case. Such protection not only shields the magnet but also improves its resistance to damage
• Neodymium magnets lose force when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop of strength (a factor is the shape as well as dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are extremely resistant to heat
• Magnets exposed to a humid environment can corrode. Therefore when using outdoors, we suggest using water-impermeable magnets made of rubber, plastic or other material resistant to moisture
• Due to limitations in realizing threads and complicated forms in magnets, we propose using a housing - magnetic mechanism.
• Possible danger to health – tiny shards of magnets are risky, if swallowed, which is particularly important in the aspect of protecting the youngest. Additionally, small components of these magnets can be problematic in diagnostics medical in case of swallowing.
• High unit price – neodymium magnets have a higher price than other types of magnets (e.g. ferrite), which can limit application in large quantities

Maximum holding power of the magnet – what it depends on?

Magnet power is the result of a measurement for the most favorable conditions, assuming:

• on a plate made of mild steel, optimally conducting the magnetic flux
• whose transverse dimension equals approx. 10 mm
• with an polished touching surface
• under conditions of no distance (surface-to-surface)
• under perpendicular force direction (90-degree angle)
• in temp. approx. 20°C

Magnet lifting force in use – key factors

Holding efficiency impacted by working environment parameters, such as (from most important):

• Gap (between the magnet and the plate), since even a tiny clearance (e.g. 0.5 mm) can cause a decrease in lifting capacity by up to 50% (this also applies to varnish, corrosion or dirt).
• Loading method – catalog parameter refers to pulling vertically. When applying parallel force, the magnet exhibits significantly lower power (typically approx. 20-30% of nominal force).
• Element thickness – to utilize 100% power, the steel must be adequately massive. Thin sheet restricts the attraction force (the magnet "punches through" it).
• Steel grade – the best choice is pure iron steel. Hardened steels may attract less.
• Surface structure – the more even the plate, the larger the contact zone and stronger the hold. Roughness creates an air distance.
• Temperature – heating the magnet results in weakening of induction. It is worth remembering the maximum operating temperature for a given model.

* Holding force was tested on the plate surface of 20 mm thickness, when the force acted perpendicularly, in contrast under attempts to slide the magnet the holding force is lower. Moreover, even a minimal clearance {between} the magnet and the plate decreases the lifting capacity.