Using speed variation to counteract chatter in a lathe

pontiac428 said:
Sine wave to represent acceleration, triangle to represent translation, right?

I think you are getting into interesting territory. Would be cool to put a mic on the tool and vary speed based on filtering frequencies out of the range where harmonics exist.
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I'm pretty sure I can get chatter/harmonics at any frequency on my lathe!
Robert
 
rwm said:
I'm pretty sure I can get chatter/harmonics at any frequency on my lathe!
Click to expand...

So true. It is all about resonances. Chatter is always some defined frequency and/or the harmonics thereof. The frequency depends on Your setup on the lathe. I am not sure whether the phase of the moon has some effect - it just might :)

One idea would be to listen to the work piece and then introduce a counteracting "sound" into the system. Much like the noise cancelling headphones. In an optimal system this would make a brass tube act as if it was made out of lead.

The system I am doing here tries to shorten the time the system is resonant on same frequency. The resonant frequency is moved around and this does not allow the chatter enough time to build up. In theory that at least ...
 
Your approach reminds me of a method that was used to reduce "howl" in PA systems. The signal from the mike is frequency shifted by a few hertz, so positive feedback at a particular frequency is thwarted. While the mechanics are different, the concepts are similar.
 
In this episode we will dive into the art of reading the keys.
In addition some talk about timers in microcontroller platform.
Finally something about ring buffers.

 
I usually just look for a way to increase rigidity in the set up or find the offending tool geometry. But hey I'm an old guy stuck in some old guy ways.
 
TakeDeadAim said:
I usually just look for a way to increase rigidity in the set up or find the offending tool geometry. But hey I'm an old guy stuck in some old guy ways.
Click to expand...
Rigidity should always be the first step in eliminating the shatter. There are situations though where the machine itself is rigid allright but the work piece is not. The work piece might have a tendency to resonate. This is where this small device should help.
 
The following video is all about A/D conversion in a microcontroller environment. Enjoy !

 
In this episode I am soldering the SMD compåonents in the PCB.

 
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