![\"Sintered](\"https:\/\/bmagmagnet.com\/wp-content\/uploads\/2026\/03\/Sintered-NdFeB-Magnet-Processing-BMAG-Magnet.webp\")
<\/a>1. The Purpose of Magnet Processing<\/h2>\n\n\n\n
Why not just sinter a magnet into its final shape? Sintering involves high heat that causes the material to shrink and warp slightly. Machining is essential to:<\/p>\n\n\n\n
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- Achieve Dimensional Accuracy:<\/strong> Bringing the magnet to the exact tolerances required for tight assemblies.<\/li>\n\n\n\n
- Improve Surface Quality:<\/strong> Removing the “sintered skin” to ensure the magnet is smooth and flat.<\/li>\n\n\n\n
- Prepare for Coating:<\/strong> Creating a surface that allows protective layers (like Nickel or Epoxy) to adhere properly.<\/li>\n\n\n\n
- Create Complex Features:<\/strong> Adding holes, chamfers, or specific arcs that pressing cannot achieve, like a countersunk magnet.<\/li>\n<\/ul>\n\n\n\n
![\"Sintered](\"https:\/\/bmagmagnet.com\/wp-content\/uploads\/2026\/03\/Sintered-NdFeB-Magnet-BMAG-Magnet.webp\")
<\/a>Sintered NdFeB Magnet- BMAG Magnet<\/a><\/figcaption><\/figure>\n\n\n\n 2. The Magnet Machining Process<\/h2>\n\n\n\n
The journey from a “blank” to a finished product involves several critical stages.<\/p>\n\n\n\n
Step 1: Pre-Cutting Grinding<\/h3>\n\n\n\n
Even though a newly sintered blank might look “neat,” its surface is microscopically rough and chemically inconsistent. Before any slicing occurs, the blank undergoes surface grinding<\/strong>. This ensures the piece is perfectly flat, providing a stable reference point for the cutting tools.<\/p>\n\n\n\n
![\"Sintered](\"https:\/\/bmagmagnet.com\/wp-content\/uploads\/2026\/03\/Sintered-NdFeB-Magnet-Blank-Grinding-BMAG-Magnet.webp\")
<\/a>Sintered NdFeB Magnet Blank Grinding – BMAG Magnet<\/figcaption><\/figure>\n\n\n\n Step 2: Slicing and Cutting<\/h3>\n\n\n\n
Large magnet blanks are sliced into multiple smaller units. Common methods include:<\/p>\n\n\n\n
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- Wire Cutting (EDM):<\/strong> Using electrical discharges to “erode” the material along a specific path.<\/li>\n\n\n\n
- Slicing:<\/strong> Using diamond-coated blades or multi-wire saws.<\/li>\n<\/ul>\n\n\n\n
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The “Allowance” Rule:<\/strong> > Manufacturers must account for “kerf”\u2014the material lost to the thickness of the cutting blade.<\/p>\n\n\n\n
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- Example:<\/strong> To produce a block magnet of L40 x W10 x H5 mm<\/strong>, you might start with a blank sized L42 x W22 x H55 mm<\/strong>.<\/li>\n\n\n\n
- From this single blank, you can yield 20 final products<\/strong> (10 pieces along the height and 2 across the width). The “extra” millimeters are the “allowance” consumed by the grinding and cutting tools.<\/li>\n<\/ul>\n<\/blockquote>\n\n\n\n
![\"Sintered](\"https:\/\/bmagmagnet.com\/wp-content\/uploads\/2026\/03\/Sintered-NdFeB-Magnet-Blank-After-Cutting-BMAG-Magnet.webp\")
<\/a>Sintered NdFeB Magnetrohling nach dem Schneiden \u2013 BMAG Magnet<\/figcaption><\/figure>\n\n\n\n Step 3: Drilling and Special Shaping<\/h3>\n\n\n\n
For ring magnets or those requiring screws, precision drilling is performed using specialized diamond-core drill machining. Because NdFeB is exceptionally brittle, technicians must strictly calibrate drilling speeds and feed rates<\/strong> to minimize mechanical stress and prevent fracturing. Throughout the process, the continuous application of cutting fluid<\/strong> is vital to reduce friction and dissipate heat, effectively preventing micro-cracks or thermal damage to the magnet\u2019s structure. This stage is also where complex features, such as countersunk holes for flush mounting, are precision-machined.<\/p>\n\n\n\n
![\"NdFeB](\"https:\/\/bmagmagnet.com\/wp-content\/uploads\/2026\/03\/NdFeB-Magnet-Drilling-BMAG-Magnet.webp\")
<\/a>NdFeB Magnet Drilling – BMAG Magnet<\/figcaption><\/figure>\n\n\n\n Step 4: Chamfering and Final Grinding<\/h3>\n\n\n\n
After cutting, the magnets often have sharp, fragile edges. Chamfering<\/strong> (rounding or beveling the edges) is performed to prevent chipping during handling. A final grinding<\/strong> pass is then conducted to ensure the surface is pristine for the subsequent coating application.<\/p>\n\n\n\n
![\"NdFeB](\"https:\/\/bmagmagnet.com\/wp-content\/uploads\/2026\/03\/NdFeB-Magnet-Automatic-Chamfering-BMAG-Magnet.webp\")
<\/a>NdFeB Magnet Automatic Chamfering – BMAG Magnet<\/figcaption><\/figure>\n\n\n\n 3. The Magnetic State During Processing<\/h2>\n\n\n\n
It is a common misconception that magnets are “magnetic” during this whole process. In reality, newly sintered NdFeB blanks are not yet magnetized.<\/strong> They possess only extremely weak residual magnetism. This is intentional; if the magnets were fully charged during machining, the fine metal dust (sludge) would stick to the tools and the workpiece, making precision impossible and creating a significant safety hazard.<\/p>\n\n\n\n
![\"NdFeB](\"https:\/\/bmagmagnet.com\/wp-content\/uploads\/2026\/03\/NdFeB-Magnet-Manual-Chamfering-BMAG-Magnet.webp\")
<\/a>NdFeB Magnet Manual Chamfering – BMAG Magnet<\/figcaption><\/figure>\n\n\n\n 4. Kritische Vorsichtsma\u00dfnahmen<\/h2>\n\n\n\n
Machining NdFeB is significantly more difficult than machining steel or aluminum due to the material’s unique properties.<\/p>\n\n\n\n
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- Cooling is Mandatory:<\/strong> NdFeB is highly flammable in powder form. Intense friction during grinding can cause the dust to ignite. Continuous liquid cooling is required to manage heat and wash away debris.<\/li>\n\n\n\n
- Zerbrechlichkeit:<\/strong> These magnets are more like ceramics than metals. They chip easily under mechanical stress, requiring specialized jigs and slow feed rates.<\/li>\n\n\n\n
- Corrosion Management:<\/strong> Because NdFeB contains high amounts of iron, the freshly machined surfaces are prone to rapid oxidation. Magnets must be cleaned and dried immediately after processing before moving to the coating stage.<\/li>\n<\/ul>\n\n\n\n
- Zerbrechlichkeit:<\/strong> These magnets are more like ceramics than metals. They chip easily under mechanical stress, requiring specialized jigs and slow feed rates.<\/li>\n\n\n\n
- From this single blank, you can yield 20 final products<\/strong> (10 pieces along the height and 2 across the width). The “extra” millimeters are the “allowance” consumed by the grinding and cutting tools.<\/li>\n<\/ul>\n<\/blockquote>\n\n\n\n
- Slicing:<\/strong> Using diamond-coated blades or multi-wire saws.<\/li>\n<\/ul>\n\n\n\n
- Improve Surface Quality:<\/strong> Removing the “sintered skin” to ensure the magnet is smooth and flat.<\/li>\n\n\n\n