Left extruder “stutters” in all but the center of the left rear quadrant of the bed. This produces a trail of dots and gaps, each about 0.5mm long although it can vary. Also, the location of this occurring can vary from] print to print. I’ve spent hours trying different slicer settings with both Cura and Prusaslicer. I printed successfully for several months before this started and can’t find any solutions that work.
Does anyone here have any suggestions?
A better description of the problem would be helpful in figuring out the cause. First ideas:
- Does the left extruder only “stutter” on the first layer or on all layers? This will help decide if it’s an extruder problem or a leveling issue.
- Did you change the filament type just before the problem occurred? If you have switched from PETG/ASA to PLA, then your heatbreak and/or nozzle may be clogged.
- Did you change your firmware just before the problem occurred? Then you’ll need to calibrate your SV04 again.
Thanks for your reply.
All layers. The extruder actually stops for about 0.5 to 1 second at each stutter, as if it ran out of instructions and was waiting for the next one.
Happens with PLA, TPU and PETG. 95% of prints in PLA. Different brands, spools, colors for each. Stripped the extruder and installed new heat break and nozzle. Recently replaced BL–touch. Feed is OK.
** Note that prints with a footprint of about 20 sq in (100 sq cm) or less will print OK if positioned centrally in the left rear quadrant**.
I’m using John Carlson’s firmware but had made many successful prints with it before this problem started. Also, his firmware is quite popular and others using it apparently don’t have this problem.
I’ve also tried different sd cards including the one supplied with the printer.
I use FreeCAD to design my own projects and export in both stl and 3mf formats. Same problem with files from Printables, Thingiverse, etc.
You may want to try some dry run tests without filament in order to make sure that the left extruder stepper motor & motor driver are still in working condition:
- Heat up left nozzle
- Remove filament from left extruder
- Connect SV04 via USB & enter following commands in Printrun/Pronterface console window line by line (alternatively put instructions in several text files & name them sequentially “#.gcode” & run them in sequence). The comments (after “;”) don’t need to be entered:
M83 ; set extrusion to relative
T0 ; select left extruder
G0 Z20 F800 ; raise extruder
M83 ; set extrusion to relative
G92 E0 ; reset left extruder
G1 F500 E100 ; test left extruder - 4" slowly forward
G1 F500 E-100 ; test left extruder - 4" slowly backwards
G1 F1500 E100 ; test left extruder - 4" medium speed forward
G1 F1500 E-100 ; test left extruder - 4" medium speed backwards
G1 F2500 E100 ; test left extruder - 4" fast speed forward
G1 F2500 E-100 ; test left extruder - 4" fast speed backwards
G1 F3500 E100 ; test left extruder - 4" v fast speed forward
G1 F3500 E-100 ; test left extruder - 4" v fast speed backwards
G92 E0 ; reset left extruder
In case the stuttering occurs repeatably:
You could try to change the X- & E-connectors on the left breakout board located at the left backside of the gantry. Then repeat the tests above, but exchange “E” with “X” ito address the extruder motor. If that test runs successful there is a problem with the left extruder driver. This might be solved by adjusting the motor current on the motherboard trim potentiometer “E1”.
If the test still fails you can change the X- & E-connectors back. Most likely the problem is located in the stepper motor or the extruder mechanics. You’ll need to dismantle the extruder & look for mechanical obstructions. Try to remove the extruder wheel and re-run the test sequence again. If the test runs successful try to assemble the extruder & try again. If thetest still fails it is highly likely that your SV04 needs a new extruder. stepper motor.
Thanks again for your reply Bjoern.
I understand most of what you are suggesting but I’m afraid I’m more likely to cause more problems if I try this myself.
At this point, I think that I’ll wait a few days and see if anyone replies that has had the same problem and solved it.
If not, there’s a 3d printer repair shop a couple of hours drive from here and I might take it there.
Thanks again for your help. I still might try what you have suggested. 
If i get this resolved I’ll post it here.
Hi,
Just an idea, check that the belts or endless screws are not damaged (if teeth are missing for example).
Good luck.
Thanks for suggestion. I’ll check the belts and sprockets (X and Y axis) again. The screws should be OK as i’m not having any problem with the Z axis.
I had a similar problem, but in my case I concluded that it was due to a loose connection in one of the cables to the step motor. It sometimes started to sound rrrrrrr on the right side of the bed, and did not extrude. Then when it came back to the left side it worked fine.