As much as I’ve enjoyed learning how to field strip the extruder, I’d rather not have had QUITE so much practice tonight.
All with PETG, prints fine for half an hour or so, then reports that it’s “printing without extruding” and sure enough I have to get the extruder off each time and there’s half melted PETG all up in its gears.
Why? I’ve tried four different rolls of PETG, it’s not a difficult print, just a 30x3x5 bar (edit: cm…so 300x30x50 in millimetres…and I need four of them) with a 3mm radius curve.
During the build it appears almost like it’s over extruding, with “blobs” of PETG gathering on the nozzle. Is my nozzle is worn already?
sigh I’m going to try one last run with Hyper PLA, fresh roll opened tonight. If that works I’ll just have to accept that the K2+ can’t really do PETG.
PS…with so many clogs, I fear the inside of the extruder housing is a little battle scarred - a few scrapes here and there, very small, but I wonder if that is now contributing to the problem?
Blobs of PETG, is it dried material and I think it might be extruding too hot. Try running a little cooler also look at your flowrate, could be too high too. Calibration tests will give an indicator.
I admire your persistence (and your banter of course).
Surely the K2+ must be able to print PETG, “one of the most printed materials”, does anyone else have the same issue ?
One can only guess that you have tried many temperature settings and such, so maybe the extruder parts are not correctly machined (possibly so minutely but enough to make it wrong) ?
Just guessing here as, like I said,"you have no doubt tried many settings)… so…
do you think that replacing it with a different one may be a solution ?
I tell it to calibrate for new material every time; the “Creality Tribal” on the left and the “runway” on the right? AM I still supposed to resort to temperature towers and XYZ cubes? I thought we had moved past that with this generation of machine?
No it’s fresh molten material, and if I change colour it’s always a majority of the new colour, though sometimes with a minor “marbling” of the old.
Yeah, with molten/softened material up in the gears, I think so too…and it does just jump to printing all my PETG at 250°C, which on this well enclosed machine I think may be excessive. I’ve also noticed that PETG taken to those temperatures has a different character; it is hard and brittle, almost vitrified (glass-like). Printed at lower temps (230-ish) it has a more resilient character, which is beneficial in many applications…
Again, I haven’t changed it because I’ve been operating on a “machine knows best” policy. Might have to review.
Ah, well, not so much, because I’ve been lulled into a false sense of security that this is a “smart” printer and can work out the best parameters for any given filament with it’s clever test patterns (see above). I’m starting to call that into doubt.
Still…I now know the inside of the extruder housing better than any man alive. It’s midnight here. If it fails again I’m going to try stripping and rebuilding it in the dark. With chopsticks. However, I’ve switched to hyper PLA and touch wood (or touch filament, I guess) it’s already at least 20% further into the print than I got with the PLA with no error message.
I am however going to put in a claim for a new housing under warranty…the scratches worry me, they’re just one more thing for the pesky PETG to grab onto and if it worked as intended, I wouldn’t be having so much trouble
If it is of any help consideration wise, with my Q1Pro I print PETG and PETG CF at 230 and 75 degrees with the lid on and door closed and all prints come out well for me.
As for PLA (with the same printer) , around 195 and 55 with the lid off and door half open and again all is well.
With the Ender3 V3SE I only print PLA but at the same 195-200 and 55 bed (no roof or door to open)
Cheers.
P.S. As a note, I have not had a blob or blockage so far (I just hope they can’t see me typing this and decide otherwise out of spite).
Have you tried a z-offset there is a sensor in the extruder that stops the motor when the flow is not enough. I use a z-offset -0,035 for petg and never had the problem again.
Visually, the printer is extruding too much if anything, until it stops. I think it’s retracting molten or at least softened material too far into its extruder housing.
You say there is petg on the nozzle. When i get that on the nozzle i always try first a z-offset thats why i recommended. Even if you extruder is extruding to much the z-offset wil fix the dirty nozzle. If then the the part wont stick or there is loose lines then that is not it. A dirty nozzle to close also give heat creep up to the extruder.
You are calibrating for the material being printed not for bed levelling, the printer has no idea what material is being printed, aside from gcode sent. Temperature tower and flowrate calibration as a minimum. I didn’t mention z-offset as that is something I thought new machines didn’t need, but it might be something to consider, I have one machine of 6 that does z-offset on its own right perfectly, the rest need a little tweak to be perfect.
Surely the K2+ must be able to print PETG, “one of the most printed materials”, does anyone else have the same issue ?
It seems like not all K2+ are the same. Kudos to those whom have a “good” machine! Ours suffers from “overheated extruder motor”, which thermally couples to the extruder rollers and causes bulged filament above it and extrusion/retraction faults. Solution - keep all “motors off”, print, “motors off” to cool (for hours.) Another user added a cool air pump and silicone hose to cool the extruder area with success. The issue is, the extruder motor never reduces current - it is always at 100%, even after print stops - so the whole area overheats. This is WITH the little fan in there running.
Looks to me like some form of gcode needs adjusting, perhaps lowering extruder stepper current and perhaps a gcode that turns off the stepper when the print is finished?
I’ve thought about trying to manually add gcode to do this, but it is a work printer, so I’d have to “teach” everyone how to do it… hoping Creality just makes a firmware patch at some point.
Cant you not just add it to the cfg file. i ask some one here in the office for legal advice of rooting the printer. Creality advertise that the printer is opensource so in my country (Netherlands ) it wont do anything to the warranty. creality have to come with proof of wrong use. The can give here warnings the want but it is not legal.
Good idea Martin, except that some users have experienced a non-bootable system after firmware update. Apparently some firmware updates try to change/reset/reload printer.cfg and fail, leading to a crash. It probably wouldn’t happen, but I’m not much of a gambling man.
Oh yes it does, because I tell it it’s generic PETG and it automatically decides that the range is 230-250 rather than the 190 to 210 for PLA.
What I thought it was doing with the “tribal” and “runway” was making an assessment within that range of the best exact point to pick, allowing for factors that we’re all aware of like different colours require different temperatures (if you didn’t know that, now you know why your black prints are always less detailed than your white…black absorbs heat faster and white radiates it (is cools down) faster. In general it means you print white hotter than black …by up to twenty degrees.
But it seems my machine is just doing a “let’s run it as hot as we can” option from a lookup table, so I have to say at this point I’m wondering what the tribal and the runway are actually for…what parameters change, and based on what assessment?
I have same result, but only with PETG. All four clogs yesterday were from “deformed” material. But if I had the same cause I’d
expect PLA to be even worse with it’s lower softening temperature, but straight after four consecutive sub 30 minute, sub-10 layer PETG fails, a 10hr PLA print produced a flawless result.
I think the machine isn’t as clever as it’s made out to be, and isn’t using, or is using wrongly, the information from it’s calibration tests to set temperature and flows (and possibly retraction).
In short, I’ve got softened PETG up in my extruder gears, and I shouldn’t have. I can’t envisage a situation where force alone is could cause the deformation of the PETG in these clogs, so temperature is the problem factor.
Either the heat break can’t cope with a 250° nozzle temperature, or the semi-molten filament is being retracted too far. The z distance is a possible cause of the “backup” too, so as many have said…time to start faffing around with settings, and the first thing I’m going to try is forcing a 230° print temp. It may not be the cause, but it may work as a solution.
I think a lot has to come down to the brand of filament when temperature is involved.
Unless I am lucky with the first print of a brand I have not used before (either PLA or PETG) and the temperature I use for it is ok, I will print a temperature tower for it and check it.
The only use I have for a generic PLA or PETG filament setting in the slicer, is to use it to modify the temperature to what I know works for the new filament and save it with the name and type of the filament.
Hope that makes sense ?
