Noise and Vibration in rotating vertical milling cutters 2

[soundanal]

Hi
I am trying to predict the noise generated in high speed face milling cutters (while cutting the surface of the workpiece). I had measured the noise generated in this process experimentally, and found two important sources (not considering the noise from spindle/motor). One is due to aerodynamics from the rotating cutter, and another is due to vibration during cutting. The significant frequencies are all at the cutting tooth passing frequency and harmonics. Both the cutter and workpiece natural frequencies do not show up in the spectral plots. So, which of the two - workpiece or cutter, is likely to be more dominant in producing this noise picked by the microphone?

More details:
The workpiece is a Al 6061 rectangular block (90mm X 90 mm X 90 mm) and the cutter is a Steel body of diameter 100 mm and tool overhang of 70 mm, with six peripheral cutting inserts.

Thanks
- Soundanal

 

[GregLocock]

Interesting project.

Can you modify the local atmosphere so that you can check whether the aerodynamic effects are significant?

If you cut a different material at the same speed presumably the aerodynamic noise should stay the same, but the mechanical cutting noise should change.

Cheers

Greg Locock

 

[alexit]

University of Michigan has done extensive research on software that "listens" to find if broken an insert or drill in the machine. Try re-cutting with much larger material block, this should decrease the workpiece frequency much. In a face mill I'd expect lots of axial vibration in the cutter (instead of radial) so a capacitive probe should be able to measure the same frequency as the microphone if the cutter is dominant.