UMS 20x8.6x4.5x7 / N38 - conical magnetic holder

Advantages and disadvantages of neodymium magnets.

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

• They retain attractive force for nearly 10 years – the loss is just ~1% (in theory),
• They possess excellent resistance to magnetism drop when exposed to external fields,
• In other words, due to the reflective surface of gold, the element gains a professional look,
• Magnetic induction on the working part of the magnet turns out to be exceptional,
• Through (adequate) combination of ingredients, they can achieve high thermal resistance, enabling action at temperatures reaching 230°C and above...
• Possibility of precise machining as well as modifying to atypical requirements,
• Universal use in high-tech industry – they are used in computer drives, electric drive systems, diagnostic systems, as well as other advanced devices.
• Relatively small size with high pulling force – neodymium magnets offer high power in small dimensions, which makes them useful in compact constructions

Cons of neodymium magnets: weaknesses and usage proposals

• They are fragile upon heavy impacts. To avoid cracks, it is worth protecting magnets using a steel holder. Such protection not only shields the magnet but also improves its resistance to damage
• We warn that neodymium magnets can lose their strength at high temperatures. To prevent this, we advise our specialized [AH] magnets, which work effectively even at 230°C.
• Due to the susceptibility of magnets to corrosion in a humid environment, we recommend using waterproof magnets made of rubber, plastic or other material immune to moisture, when using outdoors
• We recommend a housing - magnetic mechanism, due to difficulties in creating threads inside the magnet and complex forms.
• Possible danger related to microscopic parts of magnets pose a threat, if swallowed, which is particularly important in the context of child safety. It is also worth noting that tiny parts of these devices can disrupt the diagnostic process medical after entering the body.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Optimal lifting capacity of a neodymium magnet – what affects it?

The specified lifting capacity concerns the limit force, obtained under optimal environment, meaning:

• on a base made of mild steel, effectively closing the magnetic flux
• whose thickness reaches at least 10 mm
• with an ideally smooth contact surface
• without the slightest insulating layer between the magnet and steel
• for force applied at a right angle (in the magnet axis)
• at ambient temperature room level

Lifting capacity in practice – influencing factors

In real-world applications, the actual holding force results from a number of factors, ranked from the most important:

• Clearance – the presence of any layer (rust, tape, air) acts as an insulator, which reduces power steeply (even by 50% at 0.5 mm).
• Loading method – declared lifting capacity refers to detachment vertically. When applying parallel force, the magnet holds much less (often approx. 20-30% of nominal force).
• Wall thickness – the thinner the sheet, the weaker the hold. Part of the magnetic field passes through the material instead of converting into lifting capacity.
• Material type – ideal substrate is high-permeability steel. Hardened steels may attract less.
• Surface condition – smooth surfaces ensure maximum contact, which improves field saturation. Rough surfaces reduce efficiency.
• Thermal factor – hot environment reduces pulling force. Too high temperature can permanently damage the magnet.

* Lifting capacity testing was performed on a smooth plate of suitable thickness, under perpendicular forces, whereas under shearing force the load capacity is reduced by as much as fivefold. Additionally, even a small distance {between} the magnet’s surface and the plate reduces the load capacity.