Buzzing sound when moving gantry

I recently build a MPCNC machine (www.vicious1.com) and am using a 3-axis TB6600 CNC Driver board and 17 NEMA motors. There is not buzzing or other noise when the motors are idle but powered on. When the machine moves at a higher speed to home there isn't any unwanted noise. When the machine starts running the routing path there is a fair amount of buzzing or vibrating noise coming from the machine. Its hard for me to tell if its coming from the motors or some other part of the machine. Here is a link to a video of this operation: tinypic.com/r/bhax4y/9. Here is a screen shot of the LinuxCNC settings for one of the X-axis: imgur.com/9J3PLAh.

While the video quality isn't great, you can probably notice that there is very little bad noise when the machine if homing or picking up the pen to move to another location, its just when the machine is running the routing path that the noise happens. In the video the pen is not touching the table so I can rule out pen to table vibrations. When I did do actual drawing they can out great and with good dimensionality.

I did try turning down the driver current to the lowest the machine would operate and that seemed to help a little bit. Has anyone run into this kind of problem before? Because this machine uses timing belts I had to do some calculations to find setting for the stepconf program. While it looks like the dimensions are correct the machine (mostly) is working correctly I am not at all sure my settings are correct.

I think I might have fixed the problem. I changed the microstepping from 1/4 to 1/16 and the motors got really quite while running. Other than that, everything else appeared to work the same. I am going to assuming that was solution but is there an explanation why that would work? I changed the LinuxCNC motors settings and driver board accordingly.

Well that is one of the goals of microstepping...
www.nmbtc.com/step-motors/engineering/fu...f-and-microstepping/

Rick G

Thanks, that was the information I was looking for. I had seen somewhere online that it might be a resonance issue which is why I tried changing the microstepping. The machine seems to be able to move pretty fast even at 1/16 microsteps so I don't think that will be an issue for me.