How does workpiece speed affect vibration in CNC grinding?

The speed of the workpiece plays a very important role in the generation of vibrations on CNC grinding machines. Especially when rotating large workpieces, the following applies:

An unbalance of the workpiece excites the machine to chatter. This changes the exact positional relationship between the grinding wheel and the workpiece – leaving unwanted grinding marks (chatter patterns) on the workpiece surface.

Countermeasures

• Balancing: Balance large rotating workpieces before grinding to minimise unbalance forces.
• Adjust the speed: Avoid critical speed ranges (resonance ranges of the machine) and adapt the workpiece speed to the rigidity conditions.
• Optimise grinding parameters: Choose infeed and feed such that the cutting forces do not excite self-excited vibrations.
• Check the machine condition: Maintain bearings, guideways and the grinding spindle regularly – wear increases the tendency to vibrate.

Anyone who deliberately controls the workpiece speed and operates the machine in a low-vibration range achieves significantly better surface finishes and longer tool and wheel life.