Help! Vibrating motors and hotwire!!

[blake374]

Hello

I just finished building a 4 axis foam cutter and I can't get the hotwire to stop vibrating (makes terible cuts).  I have a gecko g540 and I used the trim port to adjust for slow speed smoothness of my steppers.  When I had the motors on my bench I noticed that when I jogged them they ran very smooth with no vibration.  When I ran my gcode for a couple flat shapes the motor really vibrated at the exact same speed.  I have put G64 at the top of my code and it dosn't fix the probllem

I am using desk cnc to write my code.

Help! I am using a dirrect belt drive and I really think it is causign at least some of the wire vibration.

Blake

[Tweakie.CNC]

Blake,

It could be a resolution issue with the software you are using (a curves created with 6 straight lines is a bit jerky compared with the same curve created with 60 straight lines) perhaps not set up correctly ?
Try another software to generate some code and see if you get the same results.

Tweakie.

[blake374]

Yes, I am starting to think it is the CAM program.  It is hard to find information on how to set up DeskCNC properly.

[blake374]

I believe my resolution in DeskCNC is .01 inch.  I am working to see if I can change that.  Could that cause a problem?

[ASC]

If I recall correctly DeskCNC converts arcs to segmented lines.  The resolution can be adjusted in the machine setup tab.  This is usually only a problem if CV is turned off in Mach.

[ASC]

ALSO in total agreement with you that DeskCNC lacks setup and tech support.  Making the switch to Mach was the best thing I've ever done!

[blake374]

I havn't got to arcs yet.  My wire/motors are vibrating on staight lines/shapes.

I had an interesting idea brought up in a cnc zone thread.  Could low resolution in my belt drive contribute to vibration?  I am running at around 600 steps per inch with the pulley hooked dirrectly to the motor. 

[kf2qd]

You are using a taught wire to cut with. It has many similarities to a Guitar string. Add to that the rigidity (or lack thereof) of the supports for the wire and the problem just gets worse. You might want to also go to a higher ratio between the motor and the final drive to help reduce the tendanct toward harmonics. Mount everything as rigid and stiff as possible. Anything that can vibrate is only going to vibrate worse with steppers.

Figure out what is vibrating as the machine moves (vibrating pieces tend to go fuzy as you look at them) and try to get rid of the vibration.

[ASC]

Could the hot wire be dampened somehow to reduce vibration?  Maybe some high temperature latex or hard rubber at either end?