Strange behaviour from gcode - Mach3, Fusion 360 adaptive
Hi everyone,
I'm hoping that someone might be able to help be figure out what is going on with my Mach3 milling program, 3D adaptive tool path generated in fusion360.
The adaptive tool path runs great for the first 47891 lines of code but somewhere on the next few lines the steppers make a noise like they've hit their hard limits and the machine coords are all pulled off, and by the time it runs a big linear move on line 47906, it's very obviously in the wrong place by several centimetres.
I have soft limits (I think) correctly set up: before I start the program I set the machine coords to the hard limits of the X,Y and Z axes. I then switch on soft limits and jog until the soft limits come into play, correctly.
I'm sure this is a super rookie question but it keeps happening despite the tweaks I've already made. I've been looking at different simulators and think that the issue lies in line 47892: G3 X-5.118 Y31.631 I-0.028 J0.8
Re: Strange behaviour from gcode - Mach3, Fusion 360 adaptive
What kind of a CNC controller are you using?
I had a Chinese TB6500 board that would lose steps at one particular line of one particular G-code file. Worked perfectly fine otherwise. I guess that line had just the right combination of speeds/accelerations/voltages/frequencies to cause a glitch somewhere in the circuit.
Try setting your feed rate override to 90% and running the file again.
Re: Strange behaviour from gcode - Mach3, Fusion 360 adaptive
Ran the program again and I believe the error actually arrives at line 47866: X-58.484 Y30.804
For some reason the Y moves fine on that move, but the X stays put, the stepper making the weird noise like it is hitting its limits. Throws the X coords off by 58.484mm.
I think that something in the preceding 1000 or so lines of code creates this error: I couldn't replicate the error by doing a "Run from here" from ~47000 but could replicate it when I ran from ~46000.
Thanks CitizenOfDream; I get your logic and I'd give it a try, but the same exact error happened yesterday when I was running it with much lower feedrates. I'm not sure what CNC controller it is to be honest, it is a Denford Novamill that was converted to Mach3 by someone, not sure what they used.
Re: Strange behaviour from gcode - Mach3, Fusion 360 adaptive
How good is the pc?. Not overworked?.
I've never ran that many lines in Mach before.
Can you possibly redo the cam program in Fusion and split it into parts of say 15,000-20,000 lines each?.
Could be worth a shot.
Not sure if it's that simple when doing 3D though.
Re: Strange behaviour from gcode - Mach3, Fusion 360 adaptive
Hi again, so I worked backwards incrementally from 47866, running the program from 47865, then 47847, 47804... etc
I managed to narrow it down to this block of code. If I start the program AFTER this, then it runs fine. But if I run from BEFORE this, the problem happens.
I don't know anything about gcode, but looking at these lines for anything that stands out, the only thing is the one line that is missing decimals (highlighted in bold below). I gave that three trailing zeroes but didn't fix the issue. Can anyone else make sense of this?