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

Pros as well as cons of NdFeB magnets.

Besides their immense field intensity, neodymium magnets offer the following advantages:

• They virtually do not lose strength, because even after 10 years the performance loss is only ~1% (in laboratory conditions),
• Magnets perfectly defend themselves against loss of magnetization caused by foreign field sources,
• Thanks to the reflective finish, the layer of nickel, gold-plated, or silver gives an professional appearance,
• Neodymium magnets generate maximum magnetic induction on a contact point, which increases force concentration,
• Thanks to resistance to high temperature, they can operate (depending on the shape) even at temperatures up to 230°C and higher...
• Thanks to flexibility in shaping and the capacity to adapt to unusual requirements,
• Fundamental importance in innovative solutions – they serve a role in computer drives, drive modules, medical devices, also complex engineering applications.
• Thanks to efficiency per cm³, small magnets offer high operating force, occupying minimum space,

Disadvantages of neodymium magnets:

• Brittleness is one of their disadvantages. Upon strong impact they can fracture. We recommend keeping them in a special holder, which not only secures them against impacts but also raises their durability
• Neodymium magnets lose strength 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
• They oxidize in a humid environment. For use outdoors we advise using waterproof magnets e.g. in rubber, plastic
• Limited ability of producing threads in the magnet and complex forms - preferred is a housing - magnet mounting.
• Possible danger related to microscopic parts of magnets are risky, in case of ingestion, which becomes key in the context of child health protection. Furthermore, tiny parts of these magnets are able to disrupt the diagnostic process medical after entering the body.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

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

Breakaway force was defined for optimal configuration, assuming:

• with the use of a sheet made of low-carbon steel, ensuring full magnetic saturation
• with a cross-section minimum 10 mm
• with a plane cleaned and smooth
• under conditions of ideal adhesion (metal-to-metal)
• under perpendicular force vector (90-degree angle)
• at temperature approx. 20 degrees Celsius

Lifting capacity in practice – influencing factors

It is worth knowing that the magnet holding may be lower depending on the following factors, starting with the most relevant:

• Distance – the presence of any layer (paint, tape, gap) acts as an insulator, which reduces power steeply (even by 50% at 0.5 mm).
• Load vector – highest force is reached only during pulling at a 90° angle. The shear force of the magnet along the surface is usually many times smaller (approx. 1/5 of the lifting capacity).
• Substrate thickness – to utilize 100% power, the steel must be sufficiently thick. Paper-thin metal limits the attraction force (the magnet "punches through" it).
• Material composition – not every steel attracts identically. Alloy additives weaken the interaction with the magnet.
• Plate texture – ground elements ensure maximum contact, which increases field saturation. Rough surfaces reduce efficiency.
• Temperature influence – high temperature reduces magnetic field. Too high temperature can permanently demagnetize the magnet.

* Lifting capacity was assessed by applying a polished steel plate of suitable thickness (min. 20 mm), under perpendicular detachment force, whereas under parallel forces the lifting capacity is smaller. Additionally, even a small distance {between} the magnet and the plate lowers the load capacity.