UMGGW 34x8 [M4] GW / N38 - magnetic holder rubber internal thread

Strengths and weaknesses of NdFeB magnets.

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

• They have unchanged lifting capacity, and over around 10 years their attraction force decreases symbolically – ~1% (according to theory),
• Magnets perfectly resist against demagnetization caused by foreign field sources,
• A magnet with a metallic gold surface has better aesthetics,
• Magnets are characterized by maximum magnetic induction on the active area,
• Thanks to resistance to high temperature, they can operate (depending on the shape) even at temperatures up to 230°C and higher...
• Thanks to modularity in forming and the ability to modify to individual projects,
• Huge importance in advanced technology sectors – they serve a role in mass storage devices, electric motors, advanced medical instruments, and multitasking production systems.
• Relatively small size with high pulling force – neodymium magnets offer high power in compact dimensions, which enables their usage in miniature devices

Problematic aspects of neodymium magnets: tips and applications.

• Brittleness is one of their disadvantages. Upon strong impact they can fracture. We advise keeping them in a strong case, which not only protects them against impacts but also raises their durability
• Neodymium magnets lose strength when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop of power (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 very resistant to heat
• Magnets exposed to a humid environment can rust. Therefore during using outdoors, we suggest using waterproof magnets made of rubber, plastic or other material protecting against moisture
• Limited ability of making nuts in the magnet and complicated forms - recommended is casing - magnet mounting.
• Health risk to health – tiny shards of magnets pose a threat, if swallowed, which is particularly important in the aspect of protecting the youngest. Additionally, tiny parts of these magnets are able to complicate diagnosis medical in case of swallowing.
• Due to expensive raw materials, their price is relatively high,

Breakaway strength of the magnet in ideal conditions – what affects it?

The declared magnet strength concerns the limit force, measured under ideal test conditions, specifically:

• using a sheet made of high-permeability steel, functioning as a circuit closing element
• possessing a massiveness of at least 10 mm to ensure full flux closure
• with an ground contact surface
• without any insulating layer between the magnet and steel
• during detachment in a direction perpendicular to the mounting surface
• in neutral thermal conditions

Practical aspects of lifting capacity – factors

Real force is affected by specific conditions, mainly (from priority):

• Gap (betwixt the magnet and the metal), because even a microscopic clearance (e.g. 0.5 mm) leads to a reduction in force by up to 50% (this also applies to varnish, rust or debris).
• Force direction – remember that the magnet has greatest strength perpendicularly. Under sliding down, the holding force drops drastically, often to levels of 20-30% of the maximum value.
• Base massiveness – too thin steel does not accept the full field, causing part of the flux to be lost into the air.
• Material type – ideal substrate is high-permeability steel. Stainless steels may attract less.
• Base smoothness – the smoother and more polished the plate, the larger the contact zone and stronger the hold. Roughness acts like micro-gaps.
• Thermal conditions – NdFeB sinters have a sensitivity to temperature. At higher temperatures they lose power, and in frost gain strength (up to a certain limit).

* Holding force was measured on the plate surface of 20 mm thickness, when a perpendicular force was applied, in contrast under shearing force the lifting capacity is smaller. In addition, even a minimal clearance {between} the magnet’s surface and the plate decreases the holding force.