MW 8x1.5 / N38 - cylindrical magnet

Pros as well as cons of NdFeB magnets.

Besides their remarkable field intensity, neodymium magnets offer the following advantages:

• Their strength is durable, and after approximately ten years it decreases only by ~1% (theoretically),
• They retain their magnetic properties even under strong external field,
• By covering with a shiny layer of gold, the element acquires an modern look,
• Magnetic induction on the working layer of the magnet is impressive,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their shape) at temperatures up to 230°C and above...
• Thanks to versatility in designing and the capacity to customize to individual projects,
• Wide application in innovative solutions – they serve a role in mass storage devices, brushless drives, diagnostic systems, as well as modern systems.
• Thanks to efficiency per cm³, small magnets offer high operating force, in miniature format,

Disadvantages of neodymium magnets:

• They are prone to damage upon heavy impacts. To avoid cracks, it is worth securing magnets in special housings. Such protection not only shields the magnet but also improves its resistance to damage
• 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.
• Magnets exposed to a humid environment can rust. Therefore when using outdoors, we recommend using water-impermeable magnets made of rubber, plastic or other material protecting against moisture
• Limited ability of creating threads in the magnet and complicated forms - recommended is casing - mounting mechanism.
• Potential hazard resulting from small fragments of magnets are risky, if swallowed, which becomes key in the aspect of protecting the youngest. Additionally, tiny parts of these devices are able to be problematic in diagnostics medical when they are in the body.
• Due to neodymium price, their price is relatively high,

Maximum holding power of the magnet – what affects it?

The load parameter shown concerns the peak performance, recorded under ideal test conditions, specifically:

• with the contact of a sheet made of low-carbon steel, ensuring maximum field concentration
• with a cross-section minimum 10 mm
• with an polished touching surface
• without the slightest clearance between the magnet and steel
• for force applied at a right angle (pull-off, not shear)
• in temp. approx. 20°C

What influences lifting capacity in practice

It is worth knowing that the magnet holding may be lower subject to the following factors, starting with the most relevant:

• Gap between magnet and steel – even a fraction of a millimeter of distance (caused e.g. by varnish or dirt) 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).
• Plate thickness – too thin plate does not accept the full field, causing part of the flux to be escaped to the other side.
• Material composition – different alloys reacts the same. Alloy additives weaken the attraction effect.
• Base smoothness – the smoother and more polished the surface, the larger the contact zone and stronger the hold. Roughness acts like micro-gaps.
• Thermal conditions – neodymium magnets have a sensitivity to temperature. At higher temperatures they are weaker, and at low temperatures gain strength (up to a certain limit).

* Holding force was measured on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, however under shearing force the lifting capacity is smaller. Moreover, even a slight gap {between} the magnet and the plate decreases the holding force.