SM 32x250 [2xM8] / N52 - magnetic separator

Strengths and weaknesses of neodymium magnets.

In addition to their magnetic efficiency, neodymium magnets provide the following advantages:

• They have stable power, and over nearly 10 years their performance decreases symbolically – ~1% (in testing),
• Magnets effectively defend themselves against demagnetization caused by ambient magnetic noise,
• The use of an elegant coating of noble metals (nickel, gold, silver) causes the element to present itself better,
• Magnetic induction on the top side of the magnet turns out to be strong,
• Due to their durability and thermal resistance, neodymium magnets can operate (depending on the shape) even at high temperatures reaching 230°C or more...
• Thanks to freedom in constructing and the capacity to customize to unusual requirements,
• Wide application in modern industrial fields – they are used in computer drives, drive modules, medical devices, also industrial machines.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Drawbacks and weaknesses of neodymium magnets: weaknesses and usage proposals

• At very strong impacts they can break, therefore we advise placing them in special holders. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• Neodymium magnets lose their strength 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
• Magnets exposed to a humid environment can corrode. Therefore during using outdoors, we advise using waterproof magnets made of rubber, plastic or other material protecting against moisture
• We recommend a housing - magnetic holder, due to difficulties in creating nuts inside the magnet and complex forms.
• Potential hazard resulting from small fragments of magnets pose a threat, when accidentally swallowed, which becomes key in the context of child safety. Additionally, small components of these products can complicate diagnosis medical after entering the body.
• Due to complex production process, their price exceeds standard values,

Best holding force of the magnet in ideal parameters – what it depends on?

Information about lifting capacity was defined for the most favorable conditions, assuming:

• with the contact of a sheet made of low-carbon steel, ensuring maximum field concentration
• whose thickness equals approx. 10 mm
• with a plane cleaned and smooth
• under conditions of no distance (surface-to-surface)
• during detachment in a direction perpendicular to the mounting surface
• in neutral thermal conditions

Determinants of lifting force in real conditions

Please note that the magnet holding will differ influenced by elements below, starting with the most relevant:

• Space between magnet and steel – every millimeter of separation (caused e.g. by varnish or dirt) diminishes the pulling force, often by half at just 0.5 mm.
• Force direction – catalog parameter refers to detachment vertically. When attempting to slide, the magnet exhibits significantly lower power (typically approx. 20-30% of maximum force).
• Metal thickness – the thinner the sheet, the weaker the hold. Magnetic flux passes through the material instead of generating force.
• Material type – ideal substrate is pure iron steel. Stainless steels may attract less.
• Surface structure – the smoother and more polished the plate, the better the adhesion and stronger the hold. Unevenness creates an air distance.
• Heat – neodymium magnets have a negative temperature coefficient. When it is hot they lose power, and in frost they can be stronger (up to a certain limit).

* Holding force was checked on the plate surface of 20 mm thickness, when the force acted perpendicularly, whereas under shearing force the holding force is lower. Moreover, even a slight gap {between} the magnet’s surface and the plate decreases the lifting capacity.