NCM 15x13.5x5 / N38 - channel magnetic holder

Advantages as well as disadvantages of rare earth magnets.

Apart from their consistent holding force, neodymium magnets have these key benefits:

• They have unchanged lifting capacity, and over nearly ten years their performance decreases symbolically – ~1% (in testing),
• They feature excellent resistance to weakening of magnetic properties as a result of external magnetic sources,
• The use of an shiny finish of noble metals (nickel, gold, silver) causes the element to present itself better,
• Magnetic induction on the working part of the magnet remains strong,
• Through (adequate) combination of ingredients, they can achieve high thermal strength, allowing for operation at temperatures reaching 230°C and above...
• Possibility of accurate modeling as well as adjusting to defined conditions,
• Wide application in innovative solutions – they find application in computer drives, electric motors, medical equipment, and multitasking production systems.
• Thanks to their power density, small magnets offer high operating force, in miniature format,

Disadvantages of NdFeB magnets:

• They are prone to damage upon heavy impacts. To avoid cracks, it is worth securing magnets using a steel holder. Such protection not only protects the magnet but also increases its resistance to damage
• NdFeB magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop 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 very resistant to heat
• Due to the susceptibility of magnets to corrosion in a humid environment, we advise using waterproof magnets made of rubber, plastic or other material resistant to moisture, in case of application outdoors
• Due to limitations in realizing nuts and complex shapes in magnets, we recommend using a housing - magnetic mechanism.
• Potential hazard to health – tiny shards of magnets are risky, when accidentally swallowed, which is particularly important in the context of child safety. Furthermore, small components of these devices can disrupt the diagnostic process medical after entering the body.
• With mass production the cost of neodymium magnets can be a barrier,

Maximum holding power of the magnet – what it depends on?

The lifting capacity listed is a measurement result executed under the following configuration:

• using a base made of low-carbon steel, functioning as a magnetic yoke
• possessing a massiveness of min. 10 mm to ensure full flux closure
• characterized by smoothness
• under conditions of gap-free contact (surface-to-surface)
• for force applied at a right angle (in the magnet axis)
• in stable room temperature

Determinants of practical lifting force of a magnet

In real-world applications, the real power depends on a number of factors, ranked from crucial:

• Distance – existence of foreign body (paint, dirt, air) acts as an insulator, which reduces capacity steeply (even by 50% at 0.5 mm).
• Force direction – remember that the magnet holds strongest perpendicularly. Under sliding down, the holding force drops drastically, often to levels of 20-30% of the nominal value.
• Steel thickness – insufficiently thick steel does not close the flux, causing part of the power to be escaped to the other side.
• Material type – ideal substrate is high-permeability steel. Stainless steels may have worse magnetic properties.
• Surface quality – the more even the surface, the larger the contact zone and stronger the hold. Unevenness acts like micro-gaps.
• Thermal environment – heating the magnet results in weakening of induction. Check the thermal limit for a given model.

* Lifting capacity was assessed with the use of a polished steel plate of optimal thickness (min. 20 mm), under perpendicular detachment force, in contrast under attempts to slide the magnet the holding force is lower. Moreover, even a minimal clearance {between} the magnet and the plate reduces the lifting capacity.