I am printing several full envelope prints and have had a layer shift of about 1 cm forward (x?) on 2 of my most recent prints. This happened after 24 full hours of printing so its a huge waste of filament. I’ll try to salvage it with my 3D Pen but it’s just annoying.
I’m not sure what is happening because both times it occurred while I was sleeping. Any suggestions? I checked that the belts are tight and they seem to be. The only thing I can think is that the support structures in Cura almost never stick to the build plate and I end up with a mess… the print turns out mostly fine but all tangled up but some of the mess winds up on or around the gears or belts and I’m thinking maybe a piece of loose material lodged into a belt causing it to slip. I have no way of telling because it’s clear now…
Did the print move relative to the bed, or the extruder relative to the print? Off the top of my head, the most common non-firmware cause is excessive force needed to feed filament, causing the extruder to be jerked around by the filament feed. I would check that your filament roll is rolled nicely and moves freely.
The shift occurred relative to the bed I guess (Front to back). The rolls seem to be spooled cleanly and there doesn’t seem to be much in the way of resistance. The other odd thing is that the shift occurred on 2 separate prints at roughly the same point, I’d say about 200 mm off of the print bed. It could be a huge coincidence but I’m not too sure. One thing I did notice was that the black tube that is zip tied to the frame was pretty close to the print at that point…maybe it snagged?
I struggled with this issue for a long time with with a big print and it wasn’t until I caught it happening that I finally figured out what was going on. What happened to me was the print had a design element that required it to start printing layers at a very shallow angle (think like a zero entry kids swimming pool). As the the nozzle would circumnavigate the layer in the shallowest portion of the layer that layer would slowly start curling upwards north of the layer’s elevation. As the distortion would continue, the nozzle would struggle to melt its way through the growing distorted layers on each pass. Eventually it would get so high that the nozzle couldn’t go through it and would grind the motor. Sometimes it would knock the part loose, other times it would just keep going about its business but off by however much the motor ground. The machine has no way of know where it is other than by where it just was. When it unexpectedly runs into something, that is how you can get those sorts of layer shifts.
If you carefully examine the failed part just below the level of the shift, you might find the telltale signs of this. Look for a distorted glob of material where the material built up and the nozzle kept running into it before it eventually failed.
To deal with it you can adjust how the part sits on the bed to avoid those shallow angles. I’ve also switch to Simplify3d which has a feature allowing you to have each layer start at a random location. This seems to help.
Hi the same thing happened again today but it looks like I can se what happened… the print got caught in the cable connected to the extruder and caused the whole thing to shift. Has anybody come up with a way to secure the cable so it never gets in the way? Also the supports keep failing on me and ending up a stringy mess. I’m using the PLA cura profiles for my printer… any suggestions?
