NCM 10x13.5x5 / N38 - channel magnetic holder

Strengths and weaknesses of neodymium magnets.

Apart from their consistent magnetic energy, neodymium magnets have these key benefits:

• Their power remains stable, and after approximately 10 years it decreases only by ~1% (theoretically),
• Magnets very well defend themselves against demagnetization caused by external fields,
• The use of an elegant finish of noble metals (nickel, gold, silver) causes the element to present itself better,
• The surface of neodymium magnets generates a intense magnetic field – this is one of their assets,
• Through (appropriate) combination of ingredients, they can achieve high thermal strength, allowing for functioning at temperatures reaching 230°C and above...
• Thanks to the possibility of free molding and customization to individualized needs, neodymium magnets can be manufactured in a variety of geometric configurations, which makes them more universal,
• Significant place in modern industrial fields – they are utilized in mass storage devices, motor assemblies, diagnostic systems, and industrial machines.
• Thanks to their power density, small magnets offer high operating force, in miniature format,

What to avoid - cons of neodymium magnets and proposals for their use:

• At strong impacts they can break, therefore we advise placing them in strong housings. A metal housing provides additional protection against damage and increases the magnet's durability.
• Neodymium magnets demagnetize 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 extremely resistant to heat
• 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, when using outdoors
• We recommend a housing - magnetic mechanism, due to difficulties in realizing threads inside the magnet and complicated shapes.
• Possible danger to health – tiny shards of magnets are risky, in case of ingestion, which becomes key in the aspect of protecting the youngest. It is also worth noting that 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 hinders application in large quantities

Highest magnetic holding force – what affects it?

Information about lifting capacity was determined for ideal contact conditions, including:

• using a plate made of mild steel, functioning as a ideal flux conductor
• with a cross-section minimum 10 mm
• with an ground contact surface
• with direct contact (without coatings)
• for force acting at a right angle (in the magnet axis)
• at ambient temperature approx. 20 degrees Celsius

Practical lifting capacity: influencing factors

In real-world applications, the actual holding force results from several key aspects, presented from most significant:

• 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.
• Force direction – note that the magnet has greatest strength perpendicularly. Under shear forces, the capacity drops drastically, often to levels of 20-30% of the maximum value.
• Metal thickness – the thinner the sheet, the weaker the hold. Magnetic flux penetrates through instead of generating force.
• Metal type – not every steel reacts the same. Alloy additives worsen the attraction effect.
• Surface structure – the more even the plate, the larger the contact zone and stronger the hold. Unevenness acts like micro-gaps.
• Thermal environment – temperature increase causes a temporary drop of force. Check the thermal limit for a given model.

* Lifting capacity was measured by applying a steel plate with a smooth surface of optimal thickness (min. 20 mm), under vertically applied force, whereas under shearing force the lifting capacity is smaller. In addition, even a slight gap {between} the magnet’s surface and the plate decreases the holding force.