KM HF - 22 kg - magnetic bracket

Strengths and weaknesses of neodymium magnets.

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

• Their power is durable, and after approximately 10 years it decreases only by ~1% (theoretically),
• Neodymium magnets are characterized by remarkably resistant to loss of magnetic properties caused by external field sources,
• The use of an aesthetic coating of noble metals (nickel, gold, silver) causes the element to look better,
• The surface of neodymium magnets generates a concentrated magnetic field – this is one of their assets,
• Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and are able to act (depending on the form) even at a temperature of 230°C or more...
• In view of the possibility of precise molding and adaptation to custom requirements, magnetic components can be modeled in a wide range of geometric configurations, which expands the range of possible applications,
• Significant place in modern technologies – they serve a role in computer drives, motor assemblies, diagnostic systems, also multitasking production systems.
• Compactness – despite small sizes they provide effective action, making them ideal for precision applications

Characteristics of disadvantages of neodymium magnets and proposals for their use:

• They are prone to damage upon heavy impacts. To avoid cracks, it is worth securing magnets using a steel holder. Such protection not only shields the magnet but also improves its resistance to damage
• Neodymium magnets lose 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
• Magnets exposed to a humid environment can rust. Therefore while using outdoors, we advise using waterproof magnets made of rubber, plastic or other material protecting against moisture
• Due to limitations in realizing threads and complex forms in magnets, we recommend using a housing - magnetic holder.
• Potential hazard to health – tiny shards of magnets pose a threat, if swallowed, which becomes key in the context of child safety. Furthermore, tiny parts of these devices are able to 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 can limit application in large quantities

Detachment force of the magnet in optimal conditions – what contributes to it?

The load parameter shown concerns the peak performance, obtained under optimal environment, meaning:

• using a sheet made of mild steel, acting as a magnetic yoke
• with a cross-section no less than 10 mm
• with an polished contact surface
• under conditions of gap-free contact (metal-to-metal)
• for force acting at a right angle (pull-off, not shear)
• in stable room temperature

Determinants of lifting force in real conditions

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

• Distance (betwixt the magnet and the metal), since even a tiny distance (e.g. 0.5 mm) results in a drastic drop in lifting capacity by up to 50% (this also applies to varnish, corrosion or debris).
• Direction of force – maximum parameter is available only during pulling at a 90° angle. The force required to slide of the magnet along the plate is standardly several times smaller (approx. 1/5 of the lifting capacity).
• Steel thickness – too thin sheet causes magnetic saturation, causing part of the flux to be wasted to the other side.
• Plate material – mild steel gives the best results. Higher carbon content decrease magnetic permeability and holding force.
• Smoothness – ideal contact is possible only on polished steel. Rough texture reduce the real contact area, reducing force.
• Heat – neodymium magnets have a negative temperature coefficient. At higher temperatures they lose power, and at low temperatures they can be stronger (up to a certain limit).

* Lifting capacity was determined by applying a smooth steel plate of suitable thickness (min. 20 mm), under perpendicular detachment force, whereas under attempts to slide the magnet the holding force is lower. Moreover, even a slight gap {between} the magnet’s surface and the plate reduces the load capacity.