MW 15x4 / N38 - cylindrical magnet

Advantages as well as disadvantages of neodymium magnets.

In addition to their long-term stability, neodymium magnets provide the following advantages:

• They have stable power, and over more than 10 years their attraction force decreases symbolically – ~1% (in testing),
• They retain their magnetic properties even under close interference source,
• The use of an shiny coating of noble metals (nickel, gold, silver) causes the element to have aesthetics,
• Magnetic induction on the working part of the magnet turns out to be exceptional,
• Through (adequate) combination of ingredients, they can achieve high thermal strength, enabling functioning at temperatures approaching 230°C and above...
• Due to the option of precise shaping and customization to individualized solutions, magnetic components can be manufactured in a broad palette of geometric configurations, which increases their versatility,
• Wide application in modern technologies – they serve a role in magnetic memories, drive modules, medical devices, also other advanced devices.
• Compactness – despite small sizes they provide effective action, making them ideal for precision applications

Characteristics of disadvantages of neodymium magnets: application proposals

• Susceptibility to cracking is one of their disadvantages. Upon strong impact they can fracture. We recommend keeping them in a special holder, which not only protects them against impacts but also raises their durability
• 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 durability even at temperatures up to 230°C
• Due to the susceptibility of magnets to corrosion in a humid environment, we suggest using waterproof magnets made of rubber, plastic or other material stable to moisture, in case of application outdoors
• Due to limitations in creating threads and complex shapes in magnets, we recommend using cover - magnetic mechanism.
• Potential hazard related to microscopic parts of magnets can be dangerous, if swallowed, which is particularly important in the context of child health protection. Additionally, tiny parts of these magnets are able to be problematic in diagnostics medical after entering the body.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Maximum lifting capacity of the magnet – what affects it?

The declared magnet strength represents the maximum value, recorded under ideal test conditions, namely:

• using a base made of low-carbon steel, acting as a magnetic yoke
• possessing a massiveness of minimum 10 mm to avoid saturation
• characterized by even structure
• under conditions of gap-free contact (metal-to-metal)
• under axial force vector (90-degree angle)
• in temp. approx. 20°C

Impact of factors on magnetic holding capacity in practice

During everyday use, the actual lifting capacity is determined by many variables, listed from the most important:

• Distance – existence of foreign body (rust, dirt, gap) interrupts the magnetic circuit, which reduces capacity rapidly (even by 50% at 0.5 mm).
• Force direction – declared lifting capacity refers to detachment vertically. When applying parallel force, the magnet exhibits significantly lower power (often approx. 20-30% of nominal force).
• Metal thickness – thin material does not allow full use of the magnet. Part of the magnetic field penetrates through instead of converting into lifting capacity.
• Steel grade – ideal substrate is high-permeability steel. Hardened steels may generate lower lifting capacity.
• Surface condition – smooth surfaces ensure maximum contact, which improves force. Uneven metal reduce efficiency.
• Thermal factor – high temperature weakens magnetic field. Exceeding the limit temperature can permanently demagnetize the magnet.

* Lifting capacity testing was performed on plates with a smooth surface of suitable thickness, under perpendicular forces, whereas under attempts to slide the magnet the load capacity is reduced by as much as fivefold. Additionally, even a small distance {between} the magnet’s surface and the plate decreases the lifting capacity.