MW 19x4 / N38 - cylindrical magnet

Strengths as well as weaknesses of neodymium magnets.

Besides their remarkable strength, neodymium magnets offer the following advantages:

• They virtually do not lose power, because even after 10 years the performance loss is only ~1% (according to literature),
• They retain their magnetic properties even under close interference source,
• By using a reflective layer of gold, the element has an proper look,
• Neodymium magnets ensure maximum magnetic induction on a their surface, which increases force concentration,
• Thanks to resistance to high temperature, they can operate (depending on the form) even at temperatures up to 230°C and higher...
• Possibility of individual machining as well as adjusting to defined needs,
• Fundamental importance in advanced technology sectors – they are utilized in computer drives, electric drive systems, advanced medical instruments, as well as multitasking production systems.
• Thanks to their power density, small magnets offer high operating force, with minimal size,

What to avoid - cons of neodymium magnets and ways of using them

• At strong impacts they can crack, therefore we advise placing them in strong housings. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• Neodymium magnets decrease their power under the influence of heating. As soon as 80°C is exceeded, many of them start losing their power. Therefore, we recommend our special magnets marked [AH], which maintain stability even at temperatures up to 230°C
• When exposed to humidity, magnets start to rust. To use them in conditions outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which prevent oxidation as well as corrosion.
• Limited ability of creating threads in the magnet and complex shapes - preferred is casing - mounting mechanism.
• Health risk related to microscopic parts of magnets can be dangerous, in case of ingestion, which gains importance in the aspect of protecting the youngest. Additionally, small components of these products can disrupt the diagnostic process medical after entering the body.
• High unit price – neodymium magnets cost more than other types of magnets (e.g. ferrite), which increases costs of application in large quantities

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

The load parameter shown represents the maximum value, obtained under laboratory conditions, specifically:

• with the use of a sheet made of low-carbon steel, guaranteeing maximum field concentration
• whose transverse dimension reaches at least 10 mm
• with an ideally smooth touching surface
• without the slightest clearance between the magnet and steel
• during detachment in a direction vertical to the mounting surface
• in stable room temperature

Lifting capacity in real conditions – factors

Holding efficiency is influenced by specific conditions, including (from most important):

• Distance – existence of foreign body (rust, dirt, gap) interrupts the magnetic circuit, which lowers capacity steeply (even by 50% at 0.5 mm).
• Force direction – declared lifting capacity refers to detachment vertically. When attempting to slide, the magnet exhibits significantly lower power (typically approx. 20-30% of nominal force).
• Substrate thickness – to utilize 100% power, the steel must be adequately massive. Paper-thin metal limits the attraction force (the magnet "punches through" it).
• Chemical composition of the base – low-carbon steel gives the best results. Higher carbon content lower magnetic permeability and holding force.
• Surface condition – ground elements ensure maximum contact, which improves force. Rough surfaces weaken the grip.
• Thermal factor – high temperature weakens magnetic field. Too high temperature can permanently damage the magnet.

* Lifting capacity was measured by applying a steel plate with a smooth surface of suitable thickness (min. 20 mm), under perpendicular pulling force, however under shearing force the holding force is lower. Additionally, even a small distance {between} the magnet’s surface and the plate decreases the lifting capacity.