Weird niose

[dan_nelson]

Since switching to shopbot control sofftware 3-8-10 my motors are making weird noises when they change direction ( almost like a grinding sound) But only on the x and y once they get running they sound fine. I didn't have this problem with Mach 3. I believe that all the values are good I dropped them From the carriage and ran them freely and still the noise. Any ideas ? Thanks Dan Nelson

[gerryv]

Did you remember to do the firmware update after installing the new software?

[dan_nelson]

Yep did that

[jTr]

Dan,
Still using old version of control software. On occasion, I get that "grinding" sound as well. Has something to do with the stepper motor moving at a different rate of speed, and as I understood from previous threads, the current is being fed more or less at a lower pulse frequency, or coarser "steps". Mine does this typically when doing a short jog, such as when machine moves from "0" home to my ZZero location a couple inches away.
Someone with a better understanding of the mechanics of this explained it here before, and hopefully can clarify, but all I can recall is it's not likely a problem.

jeff

[ssflyer]

I don't get "grinding" sounds, but do get an odd harmonic sometime when moving diagonally. However, this should not happen with the motors running free...

[dan_nelson]

According to Brady Watson this is called mid band resonance and can be adjusted on the drives thanks Brady

[bleeth]

Well, if it's just the harmonics that is typical of all tools (but can vary quite a bit) you can have some fun with it as Bill Y did:

http://www.youtube.com/watch?v=bYLdu_Tjhdw

or like this:

http://www.youtube.com/watch?v=ZbSKOtv6GVQ

[ssflyer]

My question is whether it could be harmonic resonance, if it still does it with the motors dropped, as the OP did. Seems to me that a harmonic resonance, almost by definition would require them to be mounted to transfer the vibrations to generate the harmonics.

[dan_nelson]

I talked to shopbot today about some other issues and asked the tech team about the harmonics they suggested that it could be a ramping issue so I'll play with the settings and see what happens