UMS 16x6.5x3.5x5 / N38 - conical magnetic holder

Pros as well as cons of neodymium magnets.

Besides their exceptional pulling force, neodymium magnets offer the following advantages:

• Their strength is durable, and after approximately 10 years it decreases only by ~1% (according to research),
• They are noted for resistance to demagnetization induced by presence of other magnetic fields,
• Thanks to the smooth finish, the plating of Ni-Cu-Ni, gold-plated, or silver gives an elegant appearance,
• The surface of neodymium magnets generates a concentrated magnetic field – this is a distinguishing feature,
• Through (appropriate) combination of ingredients, they can achieve high thermal strength, enabling action at temperatures reaching 230°C and above...
• Possibility of individual modeling as well as adapting to individual conditions,
• Versatile presence in high-tech industry – they find application in mass storage devices, motor assemblies, diagnostic systems, also other advanced devices.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Drawbacks and weaknesses of neodymium magnets and ways of using them

• Brittleness is one of their disadvantages. Upon intense impact they can fracture. We advise keeping them in a strong case, which not only protects them against impacts but also increases their durability
• Neodymium magnets decrease their strength under the influence of heating. As soon as 80°C is exceeded, many of them start losing their force. Therefore, we recommend our special magnets marked [AH], which maintain stability even at temperatures up to 230°C
• When exposed to humidity, magnets usually rust. For applications outside, it is recommended to use protective magnets, such as those in rubber or plastics, which prevent oxidation and corrosion.
• We recommend cover - magnetic mechanism, due to difficulties in creating threads inside the magnet and complex shapes.
• Health risk resulting from small fragments of magnets pose a threat, in case of ingestion, which becomes key in the context of child health protection. It is also worth noting that small elements of these magnets can be problematic in diagnostics medical in case of swallowing.
• Due to expensive raw materials, their price is higher than average,

Maximum lifting capacity of the magnet – what it depends on?

The force parameter is a result of laboratory testing executed under standard conditions:

• with the contact of a yoke made of low-carbon steel, guaranteeing full magnetic saturation
• with a thickness no less than 10 mm
• with a surface cleaned and smooth
• with zero gap (no paint)
• during pulling in a direction vertical to the plane
• at conditions approx. 20°C

Determinants of lifting force in real conditions

Please note that the application force may be lower influenced by elements below, starting with the most relevant:

• Air gap (between the magnet and the metal), because even a tiny clearance (e.g. 0.5 mm) leads to a reduction in force by up to 50% (this also applies to varnish, corrosion or dirt).
• Loading method – catalog parameter refers to pulling vertically. When attempting to slide, the magnet holds much less (often approx. 20-30% of maximum force).
• Metal thickness – thin material does not allow full use of the magnet. Part of the magnetic field penetrates through instead of generating force.
• Material composition – not every steel attracts identically. Alloy additives weaken the attraction effect.
• Surface condition – ground elements guarantee perfect abutment, which improves field saturation. Rough surfaces weaken the grip.
• Temperature – temperature increase causes a temporary drop of induction. Check the thermal limit for a given model.

* Holding force was measured on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, in contrast under shearing force the load capacity is reduced by as much as 5 times. Moreover, even a slight gap {between} the magnet’s surface and the plate decreases the load capacity.