SM 32x275 [2xM8] / N52 - magnetic separator

Strengths and weaknesses of NdFeB magnets.

Besides their high retention, neodymium magnets are valued for these benefits:

• They have stable power, and over around 10 years their attraction force decreases symbolically – ~1% (in testing),
• They possess excellent resistance to magnetic field loss due to external magnetic sources,
• In other words, due to the glossy layer of silver, the element looks attractive,
• Magnets are distinguished by huge magnetic induction on the working surface,
• Neodymium magnets are characterized by very high magnetic induction on the magnet surface and can function (depending on the form) even at a temperature of 230°C or more...
• Due to the option of accurate forming and customization to specialized projects, neodymium magnets can be created in a wide range of geometric configurations, which increases their versatility,
• Versatile presence in electronics industry – they serve a role in mass storage devices, electric drive systems, medical devices, also multitasking production systems.
• Thanks to efficiency per cm³, small magnets offer high operating force, with minimal size,

Disadvantages of neodymium magnets:

• At strong impacts they can break, therefore we advise placing them in strong housings. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• When exposed to high temperature, neodymium magnets suffer a drop in strength. Often, when the temperature exceeds 80°C, their power decreases (depending on the size, as well as shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
• Magnets exposed to a humid environment can rust. Therefore during using outdoors, we suggest using waterproof magnets made of rubber, plastic or other material protecting against moisture
• Limited possibility of producing threads in the magnet and complex shapes - recommended is cover - magnetic holder.
• Possible danger related to microscopic parts of magnets pose a threat, when accidentally swallowed, which becomes key in the context of child safety. Additionally, small components of these products are able to be problematic in diagnostics medical after entering the body.
• With large orders the cost of neodymium magnets is economically unviable,

Highest magnetic holding force – what contributes to it?

Information about lifting capacity is the result of a measurement for the most favorable conditions, assuming:

• using a base made of high-permeability steel, functioning as a magnetic yoke
• whose thickness reaches at least 10 mm
• with an ground touching surface
• with total lack of distance (without paint)
• during detachment in a direction perpendicular to the mounting surface
• at temperature room level

Practical aspects of lifting capacity – factors

Holding efficiency impacted by working environment parameters, such as (from priority):

• Gap between magnet and steel – every millimeter of separation (caused e.g. by varnish or unevenness) drastically reduces the magnet efficiency, often by half at just 0.5 mm.
• Angle of force application – highest force is available only during perpendicular pulling. The force required to slide of the magnet along the surface is standardly several times smaller (approx. 1/5 of the lifting capacity).
• Substrate thickness – for full efficiency, the steel must be adequately massive. Thin sheet restricts the attraction force (the magnet "punches through" it).
• Steel type – mild steel gives the best results. Higher carbon content decrease magnetic permeability and holding force.
• Plate texture – smooth surfaces ensure maximum contact, which increases force. Uneven metal weaken the grip.
• Temperature – heating the magnet causes a temporary drop of induction. Check the thermal limit for a given model.

* Holding force was tested on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, whereas under shearing force the holding force is lower. Additionally, even a minimal clearance {between} the magnet’s surface and the plate decreases the lifting capacity.