Neodymium NdFeB Block Magnets
Where compact size and high strength are required
Overview - Neodymium NdFeB Disc Magnets
Neodymium magnets or NdFeB or Rare Earth disc magnets are round coin-shaped Neodymium magnets of varying diameter and thickness. Generally the NdFeB disc magnets are axially magnetised i.e. one circular flat face is a North pole, the other circular flat face is a South pole with the distance between the flat faces (the disc thickness) being the distance between the poles (the magnet is magnetised along the central axis of the Neodymium disc magnet). All our NdFeB disc magnets are supplied as axially magnetised NdFeB magnets unless otherwise stated.
Diametrically magnetised Neodymium rare earth magnets are possible (i.e. the magnet is magnetised across the diameter perpendicular to the central axis - like being magnetised from 12 noon through to 6pm when looking down onto the magnet circular face). If you were to put a row of cans flat face down onto a table to form a single line of touching cans, this is how diametrically magnetised magnets would normally attract each other - point contact. We produce the majority of these as custom magnets.
The axially magnetised NdFeB rare earth disc magnets can be stacked in attraction to create thicker magnets (in multiples of the magnet thickness). Increasing the Neodymium disc magnet thickness can give an increase in magnetic output from the magnet but there is a thickness at which adding extra magnet height gives less and less performance benefit (the performance plateaus off) - if more performance is needed then a bigger diameter magnet should be considered (or ask us for advice).
So if you are not sure how thick your magnet should be then consider getting a thinner magnet and building up height by stacking until you empirically gain the performance you require. The Neodymium disc magnets can be fixed in place by using adhesives (e.g. superglue / cyanoacrylate, two part epoxies, etc). Holes can also be machined into parts for the magnets to be glued in place or inserted deeper and potted away to hide the magnet or give it extra corrosion protection. Sometimes the discs are covered to hide them e.g. in furniture making a thin wood layer is put over the magnet to hide it and improve the aesthetic appearance of higher value wooden furniture (bearing in mind that it introduces an air gap which will lower the magnetic pull force which can be gained by using thicker NdFeB magnets and/or bigger diameter NdFeB magnets). The Neodymium disc magnets give more pull force when attracting another magnet than when attracting a ferromagnetic (e.g. mild steel) part.
If more pull force is required you could either use thicker magnets (perhaps stack magnets if testing), use a bigger diameter magnet (particularly when there is a distance between the magnets), minimise any distance (usually an air gap) between attracting magnets (smaller gaps give much more performance), use a stronger magnet grade (e.g. N48 instead of N30), or use any combination of the above. In some applications, you may simply be able to double your performance by repeating your magnet system in another location (e.g. to hold a door closed, have a magnet system at the top corner and add another at the bottom corner, doubling the potential performance). Note that it typically takes 5 times less effort to slide magnets apart than to pull apart so applications where magnet pole faces can slide apart have less holding force (if possible turn them so that they pull directly away from each other to make the pull force stronger).
The Neodymium NdFeB disc magnets are, unless otherwise stated, nickel plated (usually a NiCuNi triple layer) - other platings are possible upon request. The Neodymium disc magnets are supplied either with a keeper or supplied in rows with a keeper at each end. If you are in any doubt about the choice of magnet, its size or need technical assistance, please contact us.
|Product Number||Diameter (mm)||Thickness* (mm)||Weight (g)||Pull Force (kg)||Units per pack|
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