Well it’s been awhile since I’ve ran into a serious bug. After a few days of testing there is a repeatable drift in X to the left (X-). A total of 4 prints, with something different each time, have identical results.
The summary of this is I’m running out of ideas and don’t know what could cause this, and therefore I am having trouble correcting it. This only occurs after some time, and doing 5 tests takes 30 hours. I need some way to speed up this testing.
This topo path is not predictable, nothing like bottom to top or anything, but the dark lines are cut before the lighter ones. They do not line up on top of each other in some areas, and do in others.
Total burn time for this is around 6 hours, and is around 1M lines of code.
Very obvious at the right edge, with a 1mm shift.
I have tested gcode based in G91 and also G90, and the results are identical. I have tested 2 firmware versions and there’s no change.
Here’s a couple of highlights of actual, versus the rendered in ncviewer.
Thick: Line 65,000
Thin: Line 238,000
Here’s an example of one that’s fine.
Thick: Line 21,000
Another one that’s off:
Thick: Line 7,500
Thin: Line 600,000
If anyone is interested in looking into this here’s the gcode.
mt hood-layout-sm-absolute.zip (3.9 MB)
I’m quite positive this is not a floating point rounding issue, as I did all of the floating point math in excel using both single and doubles and graphed the positional error for each line of gcode as it’s executed. This math was done on the G91 relative based gcode. Visually, the G90 and G91 results looked the same, and I don’t think this error explains anything:
The X and Y components are roughly similar, which also doesn’t match with the result of primarily X shift and not Y.
So, I can’t really think of mechanism that would cause this. Any ideas would be appreciated.