XL first layer problems with PETG, nozzle "leaks" while in "absorbing heat" mode, filament blob screws up flatness calibration?
I've noticed first layer issues. I print almost exclusively with PETG. It seems like the system should go wipe the nozzle off after it sits in "absorbing heat" mode for 7 minutes. My nozzle leaks filament that makes a blob that seems to create an offset when the system goes around probing the plate flatness.
Any easy way to add this?
RE: XL first layer problems with PETG, nozzle "leaks" while in "absorbing heat" mode, filament blob screws up flatness calibration?
I use PETG a lot too. It's simple to solve, just go to "Printer Settings" -> "Start G-code" and change this line to set the temp to 140. By default PETG is 175 and PLA is 170 and FLEX is something way high. I've done this on all the MK3S for years and works well with the XL too which I've been using for months. I bold-underlined the 3 areas I changed. Once this is done oozing goes to nothing.
M109 T{initial_tool} S{((filament_notes[initial_tool]=~/.*HT_MBL10.*/) ? (first_layer_temperature[initial_tool] - 10) : (filament_type[initial_tool] == "PC" or filament_type[initial_tool] == "PA") ? (first_layer_temperature[initial_tool] - 25) : (filament_type[initial_tool] == "FLEX") ? 140 : (filament_type[initial_tool]=~/.*PET.*/) ? 140 : 140)} ; wait for temp
RE: XL first layer problems with PETG, nozzle "leaks" while in "absorbing heat" mode, filament blob screws up flatness calibration?
Hopefully not hijacking this thread but I have an issue that may be related to this. Using a .6mm nozzle and PETG my XL has suddenly added a mysterious .2mm+ offset after heating, probing, and leveling. Just after the purge the tool runs to the start point and starts printing just above the print surface; enough to not adhere at all and just start to gum up. When watching the heating and leveling/probing I have been careful to look for blobs and stuff to throw off that leveling height and I don't think it is, or at least not .2-.8mm worth. I have tried to dial down the Z offset but it seems to be either overridden each time or is just added to when leveled. I don't know what to adjust or tweak first. Is this a slicer/config issue or a tool head adjustment issue? Any thoughts or comments appreciated. (For what its worth many early .6mm prints with all 5 tools were just fine and .4mm prints with the other 4 heads are also just fine)
RE: XL first layer problems with PETG, nozzle "leaks" while in "absorbing heat" mode, filament blob screws up flatness calibration?
I print mainly with PETG on the XL. I get plenty of oozing (or "leaking") if the filament is not properly dried. The 0.6 nozzles are merciless in revealing this problem, the 0.4 is much more forgiving. The ambient humidity where I live is around 50%-60% at this time of year. It takes less than 24 hours of a roll being out after drying for it to go from zero oozing to moderate oozing. If it's been out for a few days, the nozzle will be virtually incontinent. I've really had to up my game with filament drying, and I see this as a positive change - wet filament causes all manner of problems, so keeping it dry will improve reliability and repeatability in general. If I have a batch of spools to dry, I use my large Excalibur food dehydrator (10+ rolls at a time). For one or two rolls at a time, I use Eibos Polyphemus driers (note that the Polyphemus presets are rather optimistic as regards both temperature and time, I increase both). Then I print from a Polyphemus in humidity-control mode, keeping the roll in a 10% RH environment. If I will leave the printer unused for 12+ hours, I will unload the filament. Regardless, I either put the roll into a vacuum bag with desiccant, or leave it in a Polyphemus in humidity-control mode. With this regimen, I can print eg eSUN PETG at with the stock Generic PETG profile (including stock temperatures), 0.6 nozzle, no oozing, only very occasional whisps of stringing. And no problematic blobs to upset bed probing.
RE: XL first layer problems with PETG, nozzle "leaks" while in "absorbing heat" mode, filament blob screws up flatness calibration?
Getting back to the OP…
I see the exact same thing. IMO, the best solution is simply to manually clean off the nozzle with a paper towel before you start the print. Also, I set my presets so that all the extruders retract out of the melt zone when the tool is parked, so there’s no oozing out at the start of a print.
RE: XL first layer problems with PETG, nozzle "leaks" while in "absorbing heat" mode, filament blob screws up flatness calibration?
Also, the material presets for materials are way too hot. The new heater and hot block are oriented completely different and Prusa doesn’t seem to realize it. I now have PETG at 215c. It’s probably not actually 215c, that’s just where the setting has to be to get it to behave as it should at 235c.
RE: XL first layer problems with PETG, nozzle "leaks" while in "absorbing heat" mode, filament blob screws up flatness calibration?
Once this is done oozing goes to nothing.
Thanks Bruce, that totally fixed up my PETG 1st layer. brilliant!