Machine Tool Diagnosis by Circularity Test

Picture above: Circularity test on a gantry milling machine.

Applying Renishaw’s QC 10 measuring system we provide you with a quick, powerful and accurate check on machine performance. When the machine runs two consecutive circular arcs, clockwise and counter clockwise, QC 10 measures any deviations in the circle radius. The following parameters are measured and available on reports and plots:

  • Backlash
  • Lateral play
  • Reversal spikes
  • Servo mismatch
  • Squareness
  • Straightness
  • Scaling error
  • Centre offset
  • Circularity
  • Powerful software analysis enables diagnosis of specific machine errors. Each error is ranked according to its significance to overall machine accuracy.

    The quality of every component produced by a CNC machine tool is highly dependent on the machine’s performance. Problems with a machine invariably result in components being scrapped and machine downtime. To avoid scrap it is better to check the machine before you cut any metal.

    Advantages of QC 10 machine tool diagnosis:

  • Quick check of machine performance
  • Maintain production tolerances
  • Grade and compare machines
  • Test and monitor machine condition
  • Predict maintenance requirements
  • Reduces machine down-times and maintenance costs
  • Applicable in the context of DIN/ISO 9000
  • Kreisform-Messung
    The picture above shows a circularity measurement with two consecutive circular arcs, clockwise and counter clockwise. The spikes at the quadrant transition are clearly to see, which means the axis remains for a short moment at the same spot. The effect of this “stopping” at the quadrant transition leads to the fact, that during circular machine operation small surfaces are milled at these transition points. A possible cause may be, that after restarting in opposite direction the axis has to overcome static friction and is therefore retarding its movement.