External Grinding

External grinding is a machining process with geometrically undefined, multi-edged tools. We normally perform the external grinding task as a complementary process to a surface we have internally processed. BAHMÜLLER has established the special feature of using CBN materials for highly efficient process design when grinding to finished dimensions.

Your benefits

  • project-specific tool development in connection with our process development in the tech center
  • through CBN technology, reduction of required machines possible through process integration of pre-grinding and finish-grinding (match quality)
  • optimal process reliability and stability
  • defined burr-free and sharp-edged geometries (for better product properties)
  • maximum availability through optimal tool service life > 12 months (CBN)
  • highest output through optimized machining times and minimal auxiliary times/maximum dressing intervals (CBN)

Special features of Bahmüller external grinding technology:


  • directly driven frequency spindles with integrated dynamic balance systems
  • cutting speed of 45 – 150 m/s 
  • CBN technology for ultrafine grinding tasks (match grinding and seal seat grinding of injection industry components)
  • use of purely ceramic bonded diamond grinding wheels 
  • directly driven frequency spindles with hydraulic expanding clamping elements for dressing 
  • use of diamond shaping and diamond profile rollers
  • burr-free grinding through the simultaneous use of 2 independent tools (offset 180 degrees)
  • grinding wheel diameters of up to 600 mm
  • use of grinding wheel base bodies made of carbon fiber reinforced plastic (CFK)
  • roundness and straightness <= 0.1 μm
  • surface qualities Rz (incl. CBN) <=0.5 μm
  • cylinder shaping <=0.3 μm
  • match play tolerance for length and diameter <= +/- 0.5 µm

Between centers

  • adaptive cylinder error correction during the grinding process with piezo tailstock, use of two independent diameter measurement heads for process control
  • cylinder error correction with piezo tailstock over post-process measurement
  • multi-match grinding of up to 2 diameters and 2 lengths in one clamping
  • use of project-specific diaphragm carriers without transverse force

Chuck parts

  • with force activated clamping chucks (hydraulic, pneumatic)
  • prismatic grinding device for higher concentricity requirements
  • work piece clamping in roller assembly for deflection-critical parts with unfavorable length/diameter ratio
  • adaptive cylinder error monitoring with AE sensor equipment (sonographic gate recognition)
  • hydrostatic work piece spindle for concentricity accuracies under 0.1 µm
  • small CBN grinding tools (80 – 120mm) for highly precise grinding tasks in compact machines
  • rotating dressing process optionally on work piece spindle (speeds up to 6,000 rpm)