UMH 42x9x46 [M6] / N38 - magnetic holder with hook

Pros and cons of rare earth magnets.

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

• They have unchanged lifting capacity, and over around ten years their attraction force decreases symbolically – ~1% (according to theory),
• They do not lose their magnetic properties even under strong external field,
• In other words, due to the shiny finish of nickel, the element is aesthetically pleasing,
• The surface of neodymium magnets generates a intense magnetic field – this is one of their assets,
• Thanks to resistance to high temperature, they can operate (depending on the form) even at temperatures up to 230°C and higher...
• Considering the option of free forming and customization to custom solutions, neodymium magnets can be produced in a wide range of forms and dimensions, which expands the range of possible applications,
• Wide application in modern technologies – they are commonly used in computer drives, electric motors, advanced medical instruments, and modern systems.
• Relatively small size with high pulling force – neodymium magnets offer high power in small dimensions, which enables their usage in compact constructions

Disadvantages of neodymium magnets:

• They are prone to damage upon too strong impacts. To avoid cracks, it is worth protecting magnets in special housings. Such protection not only shields the magnet but also increases 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 very resistant to heat
• Magnets exposed to a humid environment can corrode. Therefore while 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 complex forms - preferred is cover - mounting mechanism.
• Possible danger to health – tiny shards of magnets can be dangerous, if swallowed, which is particularly important in the aspect of protecting the youngest. Additionally, small components of these products are able to disrupt the diagnostic process medical when they are in the body.
• High unit price – neodymium magnets are more expensive than other types of magnets (e.g. ferrite), which can limit application in large quantities

Detachment force of the magnet in optimal conditions – what it depends on?

Holding force of 66.00 kg is a result of laboratory testing executed under standard conditions:

• on a base made of structural steel, optimally conducting the magnetic flux
• with a thickness no less than 10 mm
• with a surface cleaned and smooth
• with total lack of distance (no impurities)
• under perpendicular force direction (90-degree angle)
• at ambient temperature approx. 20 degrees Celsius

Lifting capacity in practice – influencing factors

During everyday use, the actual lifting capacity is determined by a number of factors, presented from crucial:

• Gap between surfaces – every millimeter of distance (caused e.g. by varnish or dirt) significantly weakens the pulling force, often by half at just 0.5 mm.
• Direction of force – maximum parameter is reached only during pulling at a 90° angle. The resistance to sliding of the magnet along the surface is typically many times smaller (approx. 1/5 of the lifting capacity).
• Element thickness – for full efficiency, the steel must be adequately massive. Thin sheet restricts the lifting capacity (the magnet "punches through" it).
• Material composition – not every steel attracts identically. High carbon content weaken the attraction effect.
• Surface structure – the smoother and more polished the plate, the larger the contact zone and higher the lifting capacity. Unevenness acts like micro-gaps.
• Heat – NdFeB sinters have a negative temperature coefficient. When it is hot they are weaker, and in frost gain strength (up to a certain limit).

* Lifting capacity was determined using a smooth steel plate of suitable thickness (min. 20 mm), under perpendicular detachment force, however under attempts to slide the magnet the holding force is lower. In addition, even a small distance {between} the magnet and the plate decreases the holding force.