V3.1 Catastrophic failure - massive layer shifts
I'm starting to have layer shifts in my 3.1.
Config is:
- BRS z-upgrades
- x-axis Schleif-Tec upgrade
- self-sourced
It already printed for hours, then I stopped to wait for a new hotend, I changed the motherboard and switched to RatOS 2. I've printed a couple of little things (test cube, first layer test 350x350, benchy, etc) pretty consistently. Then when I print long and somewhat tall parts, I have some shifts. The more volumic the part is, the bigger the shift. You can see the ultimate print that shattered my ASA duct....
I've been checking the belt tension, moving the head manually everywhere to check for collision, nothing. It can print a benchy with speed, so I'm not sure what is problematic.
I've tried staying up close for the first layer, but it takes hours. I'm planning to install a camera and record constantly to see if that helps.
What would you suggest? Has anyone see this already?
Thank you!!
18 Replies
if you've triple checked all things mechanical and are sure it can move at the requested speeds with no issues, it could be the print lifting up and stopping the head moving. Do you notice any curling in the few layers it was able to put down?
Or overextruding and then the nozzle catches and causes the shift
I've done it, but maybe I "badly" checked. The fact I was able to pull a decent benchy without issue troubled me.
In this print, we can see extrusion problem, so that could explain it, but I had another print (PLA) with no overextrusion and a small shift (the bigger the part, the bigger the shift it seems).
No curling in the proper layers. At first I thought that the drag cable was catching into something, or that the belt skipped. But I have no clue.
I am willing to do any test you can suggest, at this point, I am sure of nothing :/
Sounds like you need video then, with audio
I made a video and discovered several things:
- my belt setup skips at the slight resistance from the print
- a blob of PETG is very slowly building on the nozzle of the hotend (doesn't come from above)
- filament templates for the machine are crazy too fast, the printer cannot extrude with these flows
- the hotend was too hot, with a registered temperature 15 to 20 degrees less than it should (so the heater is heating more)
In the end, I ended up:
- cleaning the hotend regularly
- creating a PETG template capped at 15mm3/s
- adjusting the template to print at 200deg
And I was able to have a decent print. I didn't know that this thermistor reading issue could cause this catastrophic failure, but it seems it was corelated.
I think we can safely close this topic, and I'll focus on this issue now: https://discordapp.com/channels/582187371529764864/1344233387589894216
Glad this is mostly resolved, best of luck with your printing!
how tight are you belts? They shouldn't skip at the "slight resistance"
I figured this would help you better than anything @blacksmithforlife 😄
1e6 is pretty tight, I would try loosing them
I re-tightened them after the incident, but I'll loosen more. Thanks.
I've been having successes since I tweaked the filament temperatures. I wouldn't have expected this to cause that to be honest!
And the temp shift is another mystery on its own.
I appreciate the help @blacksmithforlife , thanks a lot 😉
With a performance machine, you have far less margin for error
Well said @blacksmithforlife 🇺🇸!
Belts have been tensioned, I'm on the optimal tension between 500k and 800k if I get this right. Will test print again.
Thanks for your time folks, I'll keep you posted with a successful print hopefully.
I'm on the optimal tension between 500k and 800kwhat does this mean?
I thought that the ideal belt tension should be betweem 500 000 and 800 000 to work properly.
what units is that even?
I think it's unitless. It's the Power Spectral Density. I looked at this thanks to this comment https://discord.com/channels/582187371529764864/1344387843581280328/1345764604965425244.
no, that screenshot you shared is for getting the tension even. Use the other macros to see if you need to be tighter or looser
https://os.ratrig.com/docs/configuration/calibration#measure_corexy_belt_tension