MW 38x3.5 / N38 - cylindrical magnet

Advantages and disadvantages of rare earth magnets.

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

• They virtually do not lose power, because even after ten years the performance loss is only ~1% (in laboratory conditions),
• Magnets very well defend themselves against demagnetization caused by external fields,
• By using a smooth coating of gold, the element acquires an nice look,
• Magnetic induction on the working part of the magnet turns out to be exceptional,
• 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...
• Possibility of precise creating as well as modifying to defined applications,
• Key role in high-tech industry – they are utilized in magnetic memories, brushless drives, medical equipment, also industrial machines.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

What to avoid - cons of neodymium magnets: tips and applications.

• 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 improves its resistance to damage
• When exposed to high temperature, neodymium magnets experience a drop in power. Often, when the temperature exceeds 80°C, their strength decreases (depending on the size and 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 advise using waterproof magnets made of rubber, plastic or other material stable to moisture, in case of application outdoors
• Due to limitations in creating threads and complex shapes in magnets, we recommend using a housing - magnetic holder.
• Possible danger resulting from small fragments of magnets can be dangerous, in case of ingestion, which becomes key in the context of child safety. Furthermore, small elements of these magnets can be problematic in diagnostics medical when they are in the body.
• High unit price – neodymium magnets cost more than other types of magnets (e.g. ferrite), which hinders application in large quantities

Maximum lifting force for a neodymium magnet – what it depends on?

Information about lifting capacity was determined for optimal configuration, assuming:

• using a sheet made of high-permeability steel, functioning as a magnetic yoke
• possessing a thickness of minimum 10 mm to avoid saturation
• with an ground contact surface
• under conditions of gap-free contact (surface-to-surface)
• under axial force vector (90-degree angle)
• at conditions approx. 20°C

Lifting capacity in practice – influencing factors

Holding efficiency is affected by working environment parameters, such as (from priority):

• Gap (between the magnet and the plate), since even a tiny clearance (e.g. 0.5 mm) leads to a reduction in lifting capacity by up to 50% (this also applies to varnish, corrosion or dirt).
• Angle of force application – maximum parameter is reached only during pulling at a 90° angle. The shear force of the magnet along the plate is standardly several times lower (approx. 1/5 of the lifting capacity).
• Wall thickness – the thinner the sheet, the weaker the hold. Part of the magnetic field passes through the material instead of generating force.
• Material type – the best choice is high-permeability steel. Hardened steels may have worse magnetic properties.
• Surface condition – ground elements ensure maximum contact, which improves force. Rough surfaces reduce efficiency.
• Thermal factor – high temperature reduces magnetic field. Exceeding the limit temperature can permanently damage the magnet.

* Lifting capacity testing was carried out on a smooth plate of optimal thickness, under a perpendicular pulling force, however under attempts to slide the magnet the lifting capacity is smaller. Moreover, even a small distance {between} the magnet and the plate decreases the holding force.