Atypical X-axis skipping problem (solved!)
Posted: Thu Jun 25, 2015 5:00 pm
Hello MakerGear friends,
First off, I just want to say that the M2 is amazing, this coming from a guy who owns two wooden PrintrBots... simply amazing.
Now I was hoping someone could help diagnose an X-axis skipping issue I've had. I have installed a dual extruder upgrade on this M2 and it prints great 70% of the time with no problems.
Occasionally, it will randomly skip on the X axis and move about a millimeter or two left on the X and print like that for the entire print. it has ruined a lot of long prints for me already.
[See image of globe]
After doing a lot of searching on the fourms (because thats usually where I go to fix my printrbots when something like this happens) I concluded that the problem must have been some variation of acceleration settings being too high and the increased mass on the printhead may have exaggerated that. So I went into settings and at this point I've decreased them to 1000 mm/min and tweaked a few things in the firmware like this:
However, this didn't seem to fix the problem, so I thought that maybe I was just crazy and one of the heads was dragging on the prints every so often.
So I re-tensioned the X belt and added a physical Z retraction step in the code (I use Slic3r and Repetier, but i tried this on Simplify3D and the problem still occured).
Still didn't fix it.
So, I programmed it to home X and Y each layer change and I printed out two parts to the Nautilus gears from thingiverse.
And the result:
When it got to the two pillars that are on the section that attaches two of the gears It reproduced this skipping effect EACH LAYER during the return from home.
[See other Image]
I isolated this code and re-ran this section without extrusion and surely enough I was able to reproduce it again, I had several people in out lab watch it no one has any clue where the problem is. The rail is clean and lubericsted. there are no irregular teeth on the belt, the belt is taught... and this seems issue seems independent of the slicer.
Baffled, I have come to the internet, I have arecorder the phenomenon here: https://youtu.be/dYjXroCMBmM
Please help me figure this out. This printer is in our research lab and I only have a limited time to install and use it this summer.
Thanks
First off, I just want to say that the M2 is amazing, this coming from a guy who owns two wooden PrintrBots... simply amazing.
Now I was hoping someone could help diagnose an X-axis skipping issue I've had. I have installed a dual extruder upgrade on this M2 and it prints great 70% of the time with no problems.
Occasionally, it will randomly skip on the X axis and move about a millimeter or two left on the X and print like that for the entire print. it has ruined a lot of long prints for me already.
[See image of globe]
After doing a lot of searching on the fourms (because thats usually where I go to fix my printrbots when something like this happens) I concluded that the problem must have been some variation of acceleration settings being too high and the increased mass on the printhead may have exaggerated that. So I went into settings and at this point I've decreased them to 1000 mm/min and tweaked a few things in the firmware like this:
Code: Select all
#define NUM_AXIS 4 // The axis order in all axis related arrays is X, Y, Z, E
#define HOMING_FEEDRATE {50*60, 50*60, 25*60, 0} // set the homing speeds (mm/min)
#define DEFAULT_AXIS_STEPS_PER_UNIT {44.44*2,44.44*2,200*2,471.5} // default steps per unit for Ultimaker
#define DEFAULT_MAX_FEEDRATE {500, 500, 25, 25} // (mm/sec)
#define DEFAULT_MAX_ACCELERATION {1000,1000,30,10000} // X, Y, Z, E maximum start speed for accelerated moves. E default values are good for skeinforge 40+, for older versions raise them a lot.
#define DEFAULT_ACCELERATION 1000 // X, Y, Z and E max acceleration in mm/s^2 for printing moves
#define DEFAULT_RETRACT_ACCELERATION 1000 // X, Y, Z and E max acceleration in mm/s^2 for retracts
#define EXTRUDER_OFFSET_X {0.0, 31.15} // (in mm) for each extruder, offset of the hotend on the X axis
#define EXTRUDER_OFFSET_Y {0.0, 0.0} // (in mm) for each extruder, offset of the hotend on the Y axis
#define DEFAULT_XYJERK 20.0 // (mm/sec)
#define DEFAULT_ZJERK 0.4 // (mm/sec)
#define DEFAULT_EJERK 5.0 // (mm/sec)
So I re-tensioned the X belt and added a physical Z retraction step in the code (I use Slic3r and Repetier, but i tried this on Simplify3D and the problem still occured).
Still didn't fix it.
So, I programmed it to home X and Y each layer change and I printed out two parts to the Nautilus gears from thingiverse.
And the result:
When it got to the two pillars that are on the section that attaches two of the gears It reproduced this skipping effect EACH LAYER during the return from home.
[See other Image]
I isolated this code and re-ran this section without extrusion and surely enough I was able to reproduce it again, I had several people in out lab watch it no one has any clue where the problem is. The rail is clean and lubericsted. there are no irregular teeth on the belt, the belt is taught... and this seems issue seems independent of the slicer.
Baffled, I have come to the internet, I have arecorder the phenomenon here: https://youtu.be/dYjXroCMBmM
Please help me figure this out. This printer is in our research lab and I only have a limited time to install and use it this summer.
Thanks
