MW 6x6 / N38 - cylindrical magnet

Strengths as well as weaknesses of neodymium magnets.

Apart from their strong magnetic energy, neodymium magnets have these key benefits:

• They retain magnetic properties for around 10 years – the drop is just ~1% (based on simulations),
• They are noted for resistance to demagnetization induced by presence of other magnetic fields,
• A magnet with a smooth gold surface looks better,
• They show high magnetic induction at the operating surface, making them more effective,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their form) at temperatures up to 230°C and above...
• Possibility of accurate creating as well as optimizing to specific applications,
• Key role in modern industrial fields – they are utilized in HDD drives, brushless drives, precision medical tools, also multitasking production systems.
• Relatively small size with high pulling force – neodymium magnets offer impressive pulling force in small dimensions, which makes them useful in small systems

Characteristics of disadvantages of neodymium magnets: application proposals

• To avoid cracks under impact, we suggest using special steel holders. Such a solution protects the magnet and simultaneously increases its durability.
• NdFeB magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop of strength (a factor is the shape and 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 rust. Therefore during using outdoors, we recommend using waterproof magnets made of rubber, plastic or other material protecting against moisture
• Due to limitations in creating threads and complicated shapes in magnets, we propose using a housing - magnetic mechanism.
• Possible danger related to microscopic parts of magnets are risky, in case of ingestion, which gains importance in the context of child health protection. Furthermore, tiny parts of these magnets are able to be problematic in diagnostics medical in case of swallowing.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Magnetic strength at its maximum – what affects it?

Holding force of 1.99 kg is a theoretical maximum value executed under standard conditions:

• using a sheet made of high-permeability steel, acting as a magnetic yoke
• with a cross-section no less than 10 mm
• with a plane perfectly flat
• under conditions of no distance (metal-to-metal)
• during pulling in a direction vertical to the mounting surface
• in temp. approx. 20°C

Magnet lifting force in use – key factors

Please note that the working load may be lower depending on the following factors, starting with the most relevant:

• Air gap (betwixt the magnet and the metal), as even a microscopic distance (e.g. 0.5 mm) results in a drastic drop in lifting capacity by up to 50% (this also applies to varnish, rust or dirt).
• Force direction – catalog parameter refers to pulling vertically. When applying parallel force, the magnet exhibits significantly lower power (typically approx. 20-30% of nominal force).
• Base massiveness – insufficiently thick sheet does not close the flux, causing part of the power to be lost into the air.
• Steel grade – the best choice is pure iron steel. Stainless steels may have worse magnetic properties.
• Surface quality – the smoother and more polished the plate, the larger the contact zone and higher the lifting capacity. Roughness creates an air distance.
• Thermal conditions – NdFeB sinters have a negative temperature coefficient. When it is hot they lose power, and at low temperatures they can be stronger (up to a certain limit).

* Lifting capacity was assessed by applying a polished steel plate of suitable thickness (min. 20 mm), under perpendicular pulling force, whereas under shearing force the lifting capacity is smaller. Additionally, even a slight gap {between} the magnet and the plate reduces the holding force.