LEC magnetics has available Custom bonded neodymium ring magnets.

Compression Molding Bonded NdFeB Ring Magnets are strong magnets which are used for various applications. They are manufactured by binding rapid-quenching NdFeB powde mixed with resin to form a magnet by compression molding with epoxy or infection molding with nylon. The latter technique is particular effective in large volume production, though the magnetic value of products is lower than those made with compression molding because of their relatively lower density. Bonded NdFeB is easily machined. Coolants must be used while machining this material in order to avoid spontaneous combustion of powder. Machining this material removes a layer of protective coating, and re-coating for corrosion resistance may be necessary. Various shapes of high dimensional accuracy can be produced without further processing. Epoxy coating is mostly common used for bonded NdFeB magnets, nickel-plating is also used to prevent corrosion. Compression Molding Bonded NdFeB Ring Magnets

Isotropic bonded NdFeB materials can be magnetized in any direction, or with multiple poles. Special magnetizing fixtures are required in order to achieve multiple pole magnetization. isotropic resin bonded Neodymium-Iron-Boron material offers a high energy product with an exceptional resistance to demagnetisation. Capable of operating up to 120ºC. Ring magnets may be machined from discs. Being isotropic, most shapes can be magnetised in any direction. Discs or rings may have either axial or diametric poles. Minimum field strength to magnetise to saturation is 3000kA/m (37500 0e). Such multipole fixtures may cost several thousands of dollars depending on design complexity and production rate requirements. 

Hybrid magnets to create different magnetic properties

With different ratio of additives to NdFeB powder, magnetic properties of hybrid NdFeB magnets can be tuned in a wide range. Once the ratio is fixed, magnetic property fluctuation can still be limited in a narrow bank. Hybrid magnets will meet customers' specified properties.

Characteristics for the initial magnetization of NdFeB bonded magnets

Rapidly quenched NdFeB powder used for bonded magnets is multi grain with grain size of sub-micron. Powder is isotropic in magnetic properties, which results in flat increasing of remanence and intrinsic coercivity with applied field. Magnet can only be magnetized to saturation in high fields.

Bonded Magnet Advantages

Produced with high efficiency, stability and repeatability

Magnet and other part may form together in one step

Free choice of magnetizing direction-especially for multi-polar applications

High dimensional accuracy-large quantity applications with minimum post-press machining

Thin-wall ring and complex shape magnets

High resistance to corrosion