Suppression of whistling noise in idling circular saw by damping of clamping system

During idling, when the circular saw rotates with resonant frequency, the vortices generated behind the rotating teeth excite the circular saw blade to vibration and the intensive noise of discrete tones, the so-called whistling noise, occurs. Many researches deal with the problem of whistling noise because the whistling noise is frequently 10 to 20 dB(A) higher than the aerodynamic noise. The noise level of idling circular saws was measured at different rotational frequencies ranging from 25 to 65 rps (Hz) with the step of I rps. Rubber damping-rings of the same diameter as the collar and 0.3 mm thick were placed between the sawblade and the collars and the emitted noise was measured. The use of rubber damping-rings on the samples with radial slots eliminates the whistling noise completely. This damping method is simpler and cheaper than others.