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You are here: News-Archive 11/20/2019 | 22:50
Magnetfabrik Bonn GmbH

Tel.: +49(0)228 72905-0
Fax: +49(0)228 72905-37
| Our reply to the resource issues rare earth: Sensor magnets on material basis hard ferrite in plastic bonding |

Our reply to the resource issues rare earth:
Sensor magnets on material basis hard ferrite in plastic bonding

The encoder magnets introduced here are the result of the further development of our series of plastic-bound magnets for angular sensors. Our objective was

  • to provide a more economical solution compared with magnets on the material basis of rare earth metals
  • to achieve a greater independence from raw material sources in Asia
  • to realise shaping and magnetising in a single production process

We have developed an rotary encoder magnet on a hard ferrite material basis. It is produced in an injection moulding process and magnetised directly in the too. This reduces material and production costs a well as part-specific tool costs.

Summary of technical advantages of encoder magnets made of plastic-bound hard ferrite and plastic-bound NdFeB in comparison

Advantages of magnets based on hard ferrite:

  • better contour accuracy due to smaller granulation of magnetic filler
  • corrosion stability
  • no irreversible magnetic loss at high temperatures up to 150°C
  • single level safe manufacturing process

Advantages of solutions on rare-earth basis (NdFeB):

  • greater field strength, measuring distance at comparable diameter approx. 1-2 mm large
  • less possibility of external manipulation (greater coercive field)
  • smaller reversible temperature drift (approx. 13% per 100K instead of 20% per 100K), however, this also causes irreversible losses!


We are introducing a new magnet concept for a magnet for angular sensors for front-face retrieval. We can offer approx. 30% cost reduction for large serial production; the part-specific tool costs are generally also more economical.

For more information, please download our product information sheet under “Downloads” / “Brochures”.