Could anyone tell me why I am getting shifting on the edges of my prints? Vertical Holes in the center of the print line up perfectly on each layer so I do not suspect that I am skipping steps because I believe that would involve the whole layer shifting instead of the edges. I am using cura to an sd card to a lcd display with rumba electronics. Thanks so much!
Is this from a delta printer? Cartesian? Any more details you can give us? Print material, temperature, bearings, fans?
This is from a Cartesian Mendel max 2.0, jhead 0.4 mm nozzle using the Mendel max direct drive extruder. I am using 3mm pla filament and extruding at 190c. I have 1 small fan on the x axis like max bots recommends. I have a large fan blowing on the electronics below and probably the print bed. I am using blue tape and the bed is at room temp. There is slight curling at the edge but these offsets go around the whole thing.
What software are you using to print? Are you printing from an attached computer, or an LCD/SD reader?
When it’s printing, does this offset line up with the direction of travel? By that I mean, when it appears in this image to be offset to the right, do those layers coincide with the printer initially moving in that direction on th the first layer (and then the opposite too, when the print is offset to the left, does that correspond to the printer moving in that direction on the first offset layer)?
Hey Stephen thanks for the question. I am using cura in os X, I copy it to a sd card and then use an sd/lcd reader to print. I have used USB but I get errors in my print where it just stops. I apologize for having difficulty understanding your question, but it appears as if I get these offsets in both the X direction and the Y direction.
Another thing I’d say is that I am printing off a small PLA roll and the plastic is quite rigid so I manually am unspooling and increasing the diameter of the spiral by very slight bending here and there. (This object is a spool holder so I can avoid this in the future.) I do not suspect that the springiness of the filament is causing this issue, however.
Ah. I asked about the communication method because I’ve seen things like this with intermittent communication errors. But if you’re printing from an SD card that shouldn’t be able to happen.
My second set of questions was designed to get at the possibility that this is an overshoot of some kind because the motors are being overwhelmed. It’s surprisingly hard to put into words, but very easy to illustrate visually… But basically I’m thinking one possible explanation could be that every X layers (since this looks very regular) your slicing program has changed the direction of motion, and the first time it does this it causes the print head to overshoot the model slightly in that direction because the relatively heavy print head is moving too fast in that first direction changing move for the overwhelmed motors to stop it with precision.
If that is the problem, turning the trim-pots up on the steppers for those axes may help. But it’s a little tough to determine if that’s the real underlying problem from a distance and just through text. Sorry about that.
Stepper can be set too high. Also i see inconsistancy in your print temperature. The shifted layer were printed on a different temp.
Could this be the problem?
Also check that your hot end is nice and secure.
Need more pics. The staggered layers look like they are aligned to each other – that is, there is an A set and a B set of layers - the A set looks reasonably aligned, and the B set looks reasonably aligned. I suspect something is shifting on one of the axis between two states - are the layers always printed in the same CCW direction?
You might also want to check the y axis motor pully. (The teethed thingy on the shaft of the motor). It has a screw in it. Check if it is tight enough and if you can turn the pully without turning the motor.
Thanks for the replies so far! I definitely had a loose x pully problem in the past but that is for sure very tight now. I will check the y pully today, but these offsets that I get are in the X and Y direction which makes me think it is something else. In my next print I will slightly up the stepper power and decrease the acceleration (it is at 5000 which is the recommended setting but I know is high in general), and possibly the XY jerk (It is 20 mm/s, is that high?) The default acceleration is 3000, is that also too high? I know my belts are quite tight.
Joseph, it does appear that the layers are aligned with each other. I am not sure how the layers are printed in Cura. The infill definitely changes direction from layer to layer but I am not sure about the direction the outlines are printed. Anthony, it is certainly possible that the hot end is shifting around, I’ll check that too. Actually, due to the rigidity of the PLA roll maybe the curl of the filament is causing the whole hot end to move around in a reproducible pattern. My layer height is 0.2mm for a 0.4mm orifice jhead so maybe the nozzle is a little too close to the already printed layers and moves around slightly.
Mano, how can you tell from the temperature is changing in the print or were you putting for a hypothesis? I had the feeling that my temperature is generally pretty stable (within a few degrees) but I haven’t been paying super close attention. I did PID tune it previously.
was this ever sorted out?
+Stephen Jensen i saw a difference in transparency of the layers. Usually a higher temperature make more transparent prints.
But then i could be wrong…
Lyon