SM 32x200 [2xM8] / N52 - magnetic separator

Advantages and disadvantages of rare earth magnets.

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

• They do not lose strength, even during approximately 10 years – the reduction in lifting capacity is only ~1% (theoretically),
• Magnets effectively defend themselves against demagnetization caused by foreign field sources,
• By covering with a shiny layer of gold, the element gains an modern look,
• Neodymium magnets deliver maximum magnetic induction on a small area, which increases force concentration,
• Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the shape) even at high temperatures reaching 230°C or more...
• Considering the option of accurate forming and customization to individualized projects, magnetic components can be manufactured in a broad palette of shapes and sizes, which expands the range of possible applications,
• Significant place in advanced technology sectors – they find application in hard drives, brushless drives, precision medical tools, also industrial machines.
• Relatively small size with high pulling force – neodymium magnets offer strong magnetic field in compact dimensions, which enables their usage in small systems

Disadvantages of NdFeB magnets:

• To avoid cracks under impact, we suggest using special steel housings. Such a solution protects the magnet and simultaneously improves its durability.
• When exposed to high temperature, neodymium magnets suffer a drop in power. Often, when the temperature exceeds 80°C, their power decreases (depending on the size and shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
• They rust in a humid environment. For use outdoors we suggest using waterproof magnets e.g. in rubber, plastic
• Due to limitations in realizing nuts and complicated shapes in magnets, we propose using casing - magnetic mount.
• Possible danger resulting from small fragments of magnets pose a threat, in case of ingestion, which becomes key in the context of child safety. Additionally, small elements of these products are able to 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

Maximum lifting capacity of the magnet – what affects it?

Magnet power was defined for optimal configuration, assuming:

• using a sheet made of mild steel, functioning as a magnetic yoke
• with a cross-section no less than 10 mm
• with an polished touching surface
• under conditions of ideal adhesion (metal-to-metal)
• for force acting at a right angle (pull-off, not shear)
• in stable room temperature

Determinants of practical lifting force of a magnet

In real-world applications, the actual lifting capacity depends on many variables, presented from the most important:

• Distance – existence of foreign body (rust, dirt, gap) acts as an insulator, which lowers capacity steeply (even by 50% at 0.5 mm).
• Force direction – catalog parameter refers to detachment vertically. When applying parallel force, the magnet holds much less (typically approx. 20-30% of maximum force).
• Element thickness – for full efficiency, the steel must be adequately massive. Paper-thin metal limits the attraction force (the magnet "punches through" it).
• Metal type – different alloys reacts the same. High carbon content weaken the attraction effect.
• Plate texture – ground elements ensure maximum contact, which increases field saturation. Uneven metal reduce efficiency.
• Temperature influence – high temperature reduces pulling force. Exceeding the limit temperature can permanently demagnetize the magnet.

* Lifting capacity testing was performed on plates with a smooth surface of suitable thickness, under a perpendicular pulling force, however under shearing force the load capacity is reduced by as much as 75%. Moreover, even a slight gap {between} the magnet and the plate decreases the lifting capacity.