HH 25x7.7 [M5] / N38 - through hole magnetic holder

Strengths and weaknesses of rare earth magnets.

Besides their immense field intensity, neodymium magnets offer the following advantages:

• They virtually do not lose strength, because even after ten years the decline in efficiency is only ~1% (based on calculations),
• Magnets perfectly protect themselves against loss of magnetization caused by external fields,
• Thanks to the shiny finish, the coating of Ni-Cu-Ni, gold-plated, or silver gives an visually attractive appearance,
• Neodymium magnets ensure maximum magnetic induction on a small area, which ensures high operational effectiveness,
• Through (adequate) combination of ingredients, they can achieve high thermal resistance, enabling operation at temperatures reaching 230°C and above...
• Considering the possibility of precise molding and customization to unique projects, NdFeB magnets can be manufactured in a wide range of geometric configurations, which expands the range of possible applications,
• Universal use in innovative solutions – they serve a role in data components, brushless drives, diagnostic systems, also technologically advanced constructions.
• Thanks to efficiency per cm³, small magnets offer high operating force, in miniature format,

Characteristics of disadvantages of neodymium magnets: application proposals

• They are fragile upon heavy impacts. To avoid cracks, it is worth protecting magnets in a protective case. Such protection not only protects the magnet but also improves its resistance to damage
• Neodymium magnets lose strength when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of power (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 extremely resistant to heat
• 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
• We suggest a housing - magnetic mechanism, due to difficulties in creating threads inside the magnet and complicated shapes.
• Potential hazard to health – tiny shards of magnets can be dangerous, in case of ingestion, which becomes key in the context of child safety. Furthermore, small elements of these devices can be problematic in diagnostics medical after entering the body.
• Due to complex production process, their price exceeds standard values,

Maximum magnetic pulling force – what contributes to it?

The force parameter is a measurement result executed under specific, ideal conditions:

• on a plate made of mild steel, perfectly concentrating the magnetic flux
• possessing a thickness of min. 10 mm to avoid saturation
• with an ideally smooth contact surface
• without any air gap between the magnet and steel
• under vertical application of breakaway force (90-degree angle)
• at room temperature

What influences lifting capacity in practice

During everyday use, the real power depends on a number of factors, ranked from most significant:

• Space between surfaces – every millimeter of distance (caused e.g. by veneer or unevenness) drastically reduces the magnet efficiency, often by half at just 0.5 mm.
• Load vector – highest force is reached only during perpendicular pulling. The force required to slide of the magnet along the plate is usually many times lower (approx. 1/5 of the lifting capacity).
• Wall thickness – thin material does not allow full use of the magnet. Part of the magnetic field passes through the material instead of generating force.
• Metal type – not every steel attracts identically. High carbon content weaken the attraction effect.
• Surface quality – the smoother and more polished the plate, the larger the contact zone and stronger the hold. Unevenness acts like micro-gaps.
• Temperature influence – hot environment weakens pulling force. Too high temperature can permanently demagnetize the magnet.

* Lifting capacity was assessed with the use of a polished steel plate of optimal thickness (min. 20 mm), under perpendicular pulling force, in contrast under shearing force the lifting capacity is smaller. In addition, even a small distance {between} the magnet and the plate lowers the load capacity.