PLA prints with PETG support not working at all, please advice
I'm having difficulties understanding what exactly causes this issue but my 2 extruder XL (with enclosure) works perfectly for only PLA, and also perfectly for only PETG. All prusament filament. However, using the same printing settings when printing the first layers of PLA and PETG the PETG will not create a solid body, strings, clodges to nozzle etc etc. Direct after cleaning and even on the same location on the sain powder plate I can print a perfect PETG object, using the same settings and the same filament..
I have PLA in extruder 1 and PETG in extruder 2, PLA print temp 230-225 and PETG 255-250. And the same setting are used for both multiple material and singe material prints.
I tried changing the speed, temperature etc. But it allways comes down to:
- single PETG (extruder 2)--> perfect prints
- Using 2 extruders --> PETG prints with all kind of errors.
I am lost and could use some advice.
The most obvious difference is in the way the first layer is put down, in the "PETG as support" prints there is no solid infill, just a bunch of strings of PETG is layed on the bed. In these strings are the starting poiunt of all the issues...
RE: PLA prints with PETG support not working at all, please advice
I tried using both full soluble and soluble interface but interface is even more terrible (PETG is totally wrapped around nozzle)
RE: PLA prints with PETG support not working at all, please advice
I mean the point of using this filament combo is that they don't bond, so you shouldn't be that surprised that they arn't sticking to each other. Also PETG is much tricker to get to print onto PLA than the other way around. There isn't really a way to know beforehand if a spool of PETG will adhere enough to the PLA supports; you just have to do test prints beforehand and note down what works and what doesn't. If it doesn't, then use a different brand/color/spool and test that. If it does, then hope they manufacture consistently enough to keep using those specific choices.
That said, you could try adding 'anchors' at specific layer heights. Basically, insert/CAD in geometry to force supports up to specific layer heights so that perimeters have something 'better' to adhere to than the opposing filament. It can get super tryhard if you've got a complex model; may or may not work; easy to miss something and have things go bad; may mean you need some extra trimming on the final print. But its a possible tactic.
XL-5T, MK3S MMU3 || Printing with multiple nozzle-sizes: Official Guide, Unofficial || PrusaSlicer Fork || Other advanced slicer tactics || TPU
RE: PLA prints with PETG support not working at all, please advice
Yes, I am aware that they don’t bond. But the issue is that the first layer of supportmaterial (directly on the plate) is off.
it almost looks like the z-height is incorrect. Because the system probes with extruder 1 and then extruder 2 z-height is calculated wrong and thus the PETG is not correctly dispensed.
because when only printing PETG (and using extruder 2 for probing) results in a perfect first layer.
RE: PLA prints with PETG support not working at all, please advice
Then you should double check your nozzles are installed correctly: not loose, no movement up/down. Then clean your nozzles really well and rerun the nozzle offset calibrations.
XL-5T, MK3S MMU3 || Printing with multiple nozzle-sizes: Official Guide, Unofficial || PrusaSlicer Fork || Other advanced slicer tactics || TPU
RE:
I've been doing this combo for over a year without issue. You have to have your print settings right. I also recommend only printing a 1mm interface layer and design notches into your supports to help lock the material together. I've also found that printing the interface layer as all perimeters helps. The back and forth sweeping motion tends to pull up the adjacent line of filament.
Here's a video from awhile ago where I did it on a phone mount sphere.
Finished part video
RE: PLA prints with PETG support not working at all, please advice
I think I have found the issue.
On every recalibration, the z-offset changed significantly (ranging from -0.07 to +.23).
And after the x-time re-calibration when I tried to purge some PLA from nozzle 1 the nextruder was pushed out fully.
As a result the dwarf board heater connection broke, so I have allready contected prusa and I will receive a new dwarf board (good service!)
So I'll swap the dwarf board, make sure the nextruder is tightly secured and then try another run.
For now, I assume the issue was a not correctly secured nextruder...
I know that the combination of PLA and PETG works, as I use it on my Bambu X1C all the time without any issues... So hoepfully I can get it working on the Prusa as well as I need it to print bigger pieces..
@Brian, nice video!