# Dual Y Axis control



## Daner (Sep 17, 2017)

Hello all,
My Y axis is a bit jerky on cutting detailed parts.

Is there a way in Mach that can smooth this out?

It almost seems like one motar is getting signal a split sec. Before the other Y motor

Thanks


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## 4DThinker (Feb 16, 2014)

Look into G-code G64. If it has no following parameters then your CNC will come to a stop at every node on your vectors. The close/smaller the vectors are the more it will seem like the jerking you described. If you can manually send a G64P0.01 command through mach3/4 it should remedy your problem. An easier way if you have a text editor is to add that G64P0.01 to your post processor header commands area.


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## Daner (Sep 17, 2017)

4DThinker said:


> Look into G-code G64. If it has no following parameters then your CNC will come to a stop at every node on your vectors. The close/smaller the vectors are the more it will seem like the jerking you described. If you can manually send a G64P0.01 command through mach3/4 it should remedy your problem. An easier way if you have a text editor is to add that G64P0.01 to your post processor header commands area.


Hi 4D Thanks for that.
I noticed this movement when I ran my first trial Open Sign.
Im just happy that im seing some wood chips, even though my sign is a bit rough.

I want to make a sand box for the church, and carve "Sand" on the front.
I will look in the settings of Mach tomorrow for the G24.

Danny


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## dovetail_65 (Jan 22, 2008)

Your Y acceleration may simply be too high. Make sure your Y motor wires are tight at every point.

Show us the mach3 screens with velocity and acceleration.

What software are you using, are you positive you are using the correct post processor. 

Is this the open sign we all use for first cuts? If so that Gcode is rock solid. Send me the file I'll try it.

I have not had to change, add or send any manual Gcode commands for anything I have made since the 90's when I wrote my own Gcode. The post processors are so good now I have not sen a case I can remember where I had to help Mach3 get through the file, the issue is always hardware or in the mach settings in my shop. Even for ATC and touch plates and all types of other stuff I used to have to pump out a few lines of Gcode just dont require it any more, UNLESS I write the Gcode file myself. The post processors are just better than me at this point by a huge gap.

I'll run the same file on one of my desktops for comparison if you like.


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## Daner (Sep 17, 2017)

Sorry It took a while getting back here.
But I put the motor speed up and it works much better

Thanks

Danny


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## Daner (Sep 17, 2017)

It was running smoother but that was on Jog.
Im still having jerky movements in the Y travel
For example
If I clamp one side of the gantry where the Rack and pinion motor is
Then move the gantry just by hand
I get close to 1/2" movement back and forth.
Looks like bushings (rubber) on linear rails.
Could these be worn out?


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