I have run into this problem that I have not been able to find anything out there to explain.

Here is an example of the problem.
I want to pocket out a section on a board. Say 24"x36" to a depth of a half a inch. Each pass is 1/8" deep.
The first pass starts at X=36 Y=0, the router begins the pass and runs flawlessly through the first pass at 1/8". It ends that pass at X=0 Y=24. The G-Code dictates that the router move back to x=36 y=0 to start the next pass. The router lifts and then instantly the coordinates shift to X=36 when in fact it is still at X=0. So X=0 instantly becomes X=36 and its start to cut into the negative side of the original X origin.

This will also happen if there are multiple tool paths saved to one gcode document. From tool path 1 to tool path 2 it does not rapid to the correct coordinates.


I had some luck separating the each depth into separate tool paths.  but if there is a large rapid non cutting movement across the table it flakes out.

I ran the G-code through a couple simulators and it looks like it is doing the right thing so this leads me to believe its some sort of issue between Mach3 and the machine.

OK Machine Specifics / Software specifics
Aspire 8.0
Mach 2/3 Archs Inch Post Processor
Output G-Code to *.txt file
Controller board= PMDX 131 with gekko stepper drives

Any help would be greatly appreciated

It could possibly be an issue with your Mach3 settings. If you post a copy of your .xml file I will take a look. (Copy the <your profile>.xml from your mach3 folder, rename it to beaubois.xml then attach it to your reply, using the additional options tab).

Tweakie.

The router lifts and then instantly the coordinates shift to X=36

Does the stepper make a loud noise when this happens? The motor could be stalling. Try reducing the acceleration by 50% and see if it helps.

Thanks for the help. I have attached the XML file below. I fiddled with the step and dir pulse timing moving it to 5 from 2 with no love. Also if you see anything else in the XML file that looks hinky let me know. I have been using CNC Routers for a few years but am new to Mach3 so the I am climbing the learning curve now.

The axis does make a strange noise right before it happens. Almost like a loud hum. I have dropped the acceleration on the X and Y axis to see if that does the trick. I am running a tool path now that yesterday it appears I lost 2 1/2 inches on the X axis by the time it was done. It was a path of a lot of little boxes at different depths so my guess is one of those boxes is 2.5" wide.

I will let you know if the acceleration reduction does the trick.

Thanks Again
Eric

Hi Eric,

I have not yet found anything in your .xml file which may need changing but, as Gerry suggests, your X axis could be stalling.
To test this try temporarily reducing both your Velocity and Acceleration settings in Motor Tuning for both your X and Y axes by 50% (saving the changes for each axis) then report back on the result.

Tweakie.