Print not "printing" at seam of box, leaving a gap in the print.
Does anyone know what causes this ripping effect in my print?
I have made a small box project which holds batteries and a TP4056 board to power some fairy lights. I am making them with "disposable" vape batteries and fairy lights that have been recovered from the bin, so I don't want to spend too long printing or use too much filament. The fairy lights are wrapped around the box so they protect it when not in use, so the box doesn't need to be very strong.
I am using a 0.6mm nozzle but I am finding that many of the boxes have this "tearing" effect at the seam. In many cases, there is a gap at every layer of the print, making the box extremely weak in this area. I have tried a fillet but this seems to make the problem worse.
I read that arachne could be responsible for this but it still happens with arachne off and detect thin walls on.
Does anyone have any ideas about how I could tune my design or tune my printer to fix this problem? I am looking at this as a learning exercise initially, so I would like to avoid reducing the nozzle size or increasing wall thickness as these would both increase the print time significantly.
I am using a MK3S+ from 2021 and I have seen this problem with prusament and generic PLA.
Thank you for any suggestions you have.
RE: Print not "printing" at seam of box, leaving a gap in the print.
Let me guess, you are printing multiple boxes at the same time ? Its most likely filament leaking from the 0.6 nozzle during travels between islands.
There are some threads about this effect both on the forum here and also a github issue regarding it. There seem to be many contributing factors, like filament linear advance settings etc. It also seems to be more prevalent on the mini with its bowden setup but it does appear on other printers. The jury is out on if its a slicer issue or a combination of things. The github issue if you want to read it and try any of the suggestions is located here https://github.com/prusa3d/PrusaSlicer/issues/11914
I'd start with experimenting with your retraction settings for the 0.6 nozzle. With the Mk3 don't go more than 2mm.
RE: Print not "printing" at seam of box, leaving a gap in the print.
The problem also occurs when printing only one box. I believe that the printing of the perimeter starts and finishes at this point. Here is another I just printed, and a .3mf project saved from prusaslicer. Currently the retraction length is just 0.8mm. Do you think I should set it to something like 0.2mm? I don't mind about stringing, this is a functional print.
RE: Print not "printing" at seam of box, leaving a gap in the print.
A question, are you seam setting aligned or random?
RE: Print not "printing" at seam of box, leaving a gap in the print.
No project made it through. You have to zip files like that to attach them here.
RE: Print not "printing" at seam of box, leaving a gap in the print.
Seam is aligned. Thanks for the tip about files, here is a 3MF and gcode, what do you think
RE: Print not "printing" at seam of box, leaving a gap in the print.
Thanks for attaching the project file. Looking at the slice preview and turning on show travels I think your issue is a couple of things, that wall is a single perimeter, the gap is at your layer start point. However to get to that start point its travelling diagonally across from the furthest corner so in effect a long travel resulting in the missing filament on the next layer start. Single perimeter wall with travels are sometimes (often) problematic. If you aren't already doing so, start making use of the slice preview and turning on some of the extra visualisation options like show seams and travel. You can rapidly spot where the problem areas lines up. It's also good practice and can save you a lot of time and filament in wasted prints in general 🙂
I'd thicken up that single perimeter wall just on general principles and re-slice to see what effect that has on the path planning.
I played around with the seam position setting but even with Nearest it still has a long travel to get back to the start point due to planning around that single wall perimeter so I don't think that will help in this case.
I wouldn't normally recommend this but you could also experiment with Printer Settings>Extruder>Retraction>Deretraction extra length. That will push out a bit of extra filament after the retraction. Something like 0.1-0.2mm. The problem is that can cause bulges/too much material on other areas. So its one of those problematic settings.
I suspect that making that wall a bit thicker to give 2 perimeters will be the best route.
RE: Print not "printing" at seam of box, leaving a gap in the print.
I tried printing with a random seam and there was no improvement at all but stringing did get worse.
Interestingly, the problem isn't occurring where all the deretractions are occurring but in another corner, highlighted in this photo.
I have attached the GCode and 3MF file.
After this I tried increasing the wall thickness from 0.68mm to 1.2mm, which of course means two perimeters are required. This has solved the problem and increased filament use from 20.6 g to 21.6 g, increasing print time from 50m to 51m. So, thanks for making me try that, I guess I had just pushed the optimisation too far without thinking.
I greatly appreciate your taking the time to teach me and share your experience here.