Injection Molded Magnets | Arnold Magnetic Technologies
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Injection Molded Magnets

Injection molded magnets are essentially fully dense magnetic powders blended with a variety of polymer base materials.  Depending on the combination of magnetic material and polymer selected, a wide range of final material properties are possible.

Arnold typically works with a wide ranging combination of magnetic materials and polymers including:

  • Ferrite
  • NdFeB
  • SmCo
  • Nylon 6
  • Nylon 12
  • PPS

Selecting the right combination will impact the resistance of the product to moisture absorption, physical strength, magnetic properties, and even maximum operating temperature.

Injection molded magnets can be formed from very simple shapes to very complex shapes. Depending on the magnetic material, the parts may require magnetic orientation during the injection molding process to optimize the magnetic properties.

Temperature Characteristics

Maximum use temperature is a function of both the magnetic alloy powder and of the binder. For example, ferrite powders in nylon 6 or PPS have tested satisfactorily at 180°C. On the other hand, nylon 12 melts above 170°C and is not recommended for use above 150°C. Magnetic material such as the highest energy NdFeB grade, with intrinsic coercivity of 9,500 Oersteds (760 kA/m), suffers significant irreversible magnetic loss above 120°C, regardless of which binder is used. Maximum use temperatures are listed on each product's specification sheet.

Tolerances

An important characteristic of injection molded magnets is that they conform dimensionally to the mold cavity which is precisely machined, the result being close tolerances in the finished product. What little dimensional variability there is results from shrinkage of the polymer during cooling. This depends upon part thickness and shape. Typical tolerances are +/-0.003 in/in. Closer tolerances on critical dimensions can be negotiated.

Product Availability Guide

Part No. Magnetic Material Polymer Density (g/cc) Max. Br (Gauss) Max. Hc (Oe) Max. Hci (Oe) Max. Bhmax (MGOe) Max. Temp (ºC)
2039 SrFerrite Nylon 6 3.80 3,070 2,570 3,070 2.35 160
2040 SrFerrite Nylon 12 3.75 3,060 2,540 3,190 2.34 150
2046 SrFerrite Nylon 6 3.58 2,890 2,550 3,150 2.11 160
2048 SrFerrite Nylon 6 3.55 2,880 2,510 3,210 1.99 160
2049 SrFerrite Nylon 12 3.21 2,460 2,340 3,600 1.52 150
2051 SrFerrite Nylon 6 3.76 3,130 2,590 3,140 2.41 160
2052 SrFerrite PPS 3.65 2,880 2,530 3,320 2.05 180
2070 SrFerrite Nylon 12 3.63 2,940 2,520 3,190 2.17 150
2071 SrFerrite Nylon 12 3.53 2,810 2,680 4,020 2.05 150
2101 SmCo Nylon 12 5.60 6,880 6,000 11,600 11.28 150
2103 SmCo Nylon 6 5.50 6,380 6,000 28,000 9.72 160
2202 NdFeB Polyamide 4.85 5,800 4,320 10,000 7.15 125
2204 NdFeB Nylon 12 5.20 5,390 4,920 13,200 5.94 150
2206 NdFeB PPS 4.40 4,400 4,000 10,500 4.26 150
2212 NdFeB Nylon 12 4.90 5,720 4,320 9,000 6.63 150
2213 NdFeB Nylon 12 5.20 5,890 5,000 10,000 7.44 150
2214 NdFeB Nylon 12/Polyamide 4.65 4,800 4,200 9,840 5.56 125
2216 NdFeB Nylon 12 5.16 6,110 4,800 9,000 6.63 125
2217 NdFeB PPS 4.90 4,820 4,800 18,000 5.17 180
2218 NdFeB Nylon 12 5.20 5,890 4,800 9,600 7.44 150
2225 NdFeB Special plastic 5.70 6,800 5,800 10,200 9.4 150
2409 SrFerrite/NdFeB Nylon 12/Polyamide 4.15 4,620 2,880 4,320 3.43 125
2413 SrFerrite/NdFeB Nylon 12/Polyamide 4.72 5,200 2,640 4,400 4.77 125
2414 SrFerrite/NdFeB Nylon 12 4.85 5,300 4,100 9,100 5.95 150
2415 SrFerrite/NdFeB Nylon 12 4.00 3,870 2,830 4,220 3.03 150
2416 SrFerrite/NdFeB Nylon 12 4.97 5,400 4,310 9,400 6.31 150
2417 SrFerrite/NdFeB Nylon 6 3.85 2,200 1,740 2,640 1.01 150
2521 SrFerrite Nylon 12 3.65 2,810 2,680 4,020 2.05 150
2534 SrFerrite Nylon 6 3.53 2,730 2,250 3,300 1.89 150
2535 SrFerrite Nylon12/Polyamide 3.65 2,840 2,650 4,000 1.96 125
2560 SrFerrite Polyamide 3.65 2,840 2,650 4,000 1.96 125