UMS 16x6.5x3.5x5 / N38 - conical magnetic holder

Advantages and disadvantages of rare earth magnets.

In addition to their pulling strength, neodymium magnets provide the following advantages:

• They have stable power, and over more than ten years their performance decreases symbolically – ~1% (in testing),
• Magnets perfectly defend themselves against loss of magnetization caused by foreign field sources,
• A magnet with a smooth nickel surface has an effective appearance,
• The surface of neodymium magnets generates a powerful magnetic field – this is a key feature,
• 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...
• Considering the ability of free forming and customization to unique solutions, NdFeB magnets can be created in a variety of shapes and sizes, which amplifies use scope,
• Key role in modern industrial fields – they serve a role in computer drives, brushless drives, diagnostic systems, also industrial machines.
• Relatively small size with high pulling force – neodymium magnets offer strong magnetic field in tiny dimensions, which makes them useful in small systems

Disadvantages of neodymium magnets:

• At strong impacts they can crack, therefore we recommend placing them in special holders. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• When exposed to high temperature, neodymium magnets experience a drop in force. Often, when the temperature exceeds 80°C, their strength decreases (depending on the size, as well as 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 recommend using waterproof magnets made of rubber, plastic or other material resistant to moisture, in case of application outdoors
• Limited possibility of making threads in the magnet and complex forms - recommended is cover - magnet mounting.
• Health risk to health – tiny shards of magnets are risky, in case of ingestion, which gains importance in the context of child safety. Furthermore, tiny parts of these devices are able to disrupt the diagnostic process medical when they are in the body.
• With mass production the cost of neodymium magnets is economically unviable,

Maximum holding power of the magnet – what contributes to it?

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

• using a sheet made of high-permeability steel, acting as a ideal flux conductor
• possessing a thickness of min. 10 mm to avoid saturation
• characterized by even structure
• under conditions of ideal adhesion (surface-to-surface)
• under axial force direction (90-degree angle)
• at conditions approx. 20°C

Key elements affecting lifting force

Real force is affected by working environment parameters, including (from priority):

• Clearance – existence of any layer (paint, dirt, gap) acts as an insulator, which lowers power steeply (even by 50% at 0.5 mm).
• Force direction – note that the magnet holds strongest perpendicularly. Under shear forces, the holding force drops significantly, often to levels of 20-30% of the nominal value.
• Substrate thickness – for full efficiency, the steel must be adequately massive. Thin sheet restricts the lifting capacity (the magnet "punches through" it).
• Steel type – low-carbon steel gives the best results. Higher carbon content lower magnetic properties and lifting capacity.
• Surface quality – the smoother and more polished the surface, the better the adhesion and higher the lifting capacity. Unevenness creates an air distance.
• Temperature – heating the magnet causes a temporary drop of force. It is worth remembering the maximum operating temperature for a given model.

* Holding force was tested on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, however under parallel forces the load capacity is reduced by as much as fivefold. In addition, even a slight gap {between} the magnet and the plate decreases the load capacity.