[Troubleshooting] Cannot fix a clogging issue.
[Troubleshooting] Cannot fix a clogging issue.
Hi everyone, I'm having constant clogging issues with my printer that sprung up out of nowhere. I'm running out of things to test.
The printer had been running several prints a day for several days when I decided to change nozzles for one print. Ever since then (~2 weeks ago) i have not completed a single print, due to clogging. I have tried:
Replacing the PTFE tubing in my hotend.
Replacing the nozzle. (I've used a handful of nozzles, all with the same results)
Trying different filament.
Replacing the hot end with an all metal hot end, trying three different heat breaks from two manufacturers.
Removing the printer from its enclosure to ensure proper cooling.
Adjusting extrusion tensioner.
All the other basic obvious stuff like making sure there's no blockages anywhere (whole hot end and nozzles have been soaked in acetone, torched, brushed etc).
The printer will seem to work fine for a little while before either slowly failing to extrude until it completely jams, or it completely jams all at once. I don't think it's heat creep, because I tried setting the nozzle to printing temp, letting it sit for half an hour or so and running filament through it and it had no issue, whereas prints usually start to fail within the first 10 minutes. It also doesn't have anything to do with my print settings because I'm able to get it to clog sometimes by just running the extrude command.
I'm completely at a loss here. I don't know what else to try. Does anyone have anywhere else for me to look?
Update: I tried detaching the heat block from the rest of the printer and running filament through the (cold) heat break, and it got clogged. There was a small bit of filament adhered to the inside of the heat break. So it's apparent that's where the clog is forming, it's just a matter of finding out why it's happening. Everything seems to point towards heat creep, but even when I intentionally try to heighten the conditions that to cause heat creep I can't intentionally replicate the clog. I'll keep experimenting down that route, though.
Update 2: After clearing that clog, I noticed the short piece of Bowden tube between the top of the heat break and the top of the heat sink was slightly too short. I modified the heat sink to bypass this short piece altogether; the Bowden tube now goes directly from the extruder into the heat sink to the top of the heat break. I also applied a thin layer of thermal paste to the outside of the heat break to ensure good contact/ heat transfer with the heat sink.
After doing all of this, I ran a PID tune and, with my AC set to lower than average, started extruding filament. After extruding ~300mm of filament, I tried a few nozzle and filament swaps using very careful techniques to avoid leaving any residue. I'm able to pull the filament out in a solid piece to where I can see light through the nozzle afterwards. Then, finally, out of the blue, the clicking returns. Another clog. I wasn't able to remove the filament as cleanly this time to inspect the clog, but I'm strongly suspecting heat creep at this point, despite going above and beyond to mitigate it. It's quite late though and I've got work tomorrow so it'll have to wait until then.
I recently moved to an all metal hotend on my S1 plus and had an issue with clogging. Turned out that there was a little gap between the heartbreak and the nozzle which was causing clogging. After a good tightening, it worked well.
Make sure there is no gap between your Bowden/break/nozzle. Check if any filament is seeping between them.
Any recent software changes?
I've tested and verified that there isn't a gap between the two by following this process:
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Tighten the heat break all the way.
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Tighten the nozzle all the way.
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Loosen the heat break partially.
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Verify that the nozzle is now able to be tightened further.
If the nozzle goes in further after loosening the heat break, this confirms there is no gap; however, if either nozzle or heat break isn't perfectly flat, it could theoretically leave a tiny space. I don't know if this is a common issue, but I've tried with multiple heat breaks and nozzles, so I don't think this is it.
Stupid question, but there isn't any kind of "gasket" that is meant to go between the nozzle and heat break is there? I can't shake the feeling this spot is the cause of my concerns.
It sounds like you've done it perfectly. I'd suggest trying a different heatblock, but I doubt that would make a difference. Make sure they are all aligned in your extruder with no obstruction when you look through end to end.
I've had to do some heating and cleaning of my heatblock and heatbreak when replacing parts to remove bits of plastic. (Gentle wire brush and a burner lighter).
The only other thing that comes to mind is your thermistor or heatblock cartridge being damaged and reporting the wrong temperature. Temps too high or too low can lead to clogging.
If I were you and I had tried all these things, I would get a new extruder and see if that fixes the issue.
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Since you've already excluded a damaged nozzle and other parts, I'm gonna suggest heatcreep.
Maybe the extruder fan broke, so heat creeping up the extruder and melting the filament before it should?
Do you know of any ways to test/ eliminate heat creep as a cause? I keep seeing it as a possibility but I've tried a couple things and I don't think it's that. The printer has been running in the same enclosure for ~ one year, but I took it out to make sure it's getting cool air to the extruder, I've tried heating the nozzle to printing temps and leaving the filament in the nozzle for a long time before extruding (trying to purposely replicate heat creep), and I've tried simply touching the heat sink after it's been at temp for a while and it's still barely warm to the touch.
What printer and nozzles are you using?
Did you damage the thermistor or the heater cartridge during the first nozzle swap? Could be that damage is preventing it from getting/staying at the correct temperature.
Did you double check the slicer settings are correct?
Printer is an Elegoo Neptune 3. Nozzles are just some generics I got off Amazon. I know people like to harp on quality nozzles, but I've been using them for around a year, and I don't think that all of them suddenly stopped working. Some of the ones I've tried are brand new as well, so even if the nozzles all got worn down beyond use at the exact same time (despite drastically different print times between the different sizes), the new ones should at least be able to extrude filament.
Thermistor and cartridge are undamaged. I haven't done anything to specifically test the temperature of the nozzle, but heat isn't the issue as filament still oozes out of the nozzle during clogs.
As stated above, I'm able to replicate this outside of prints, so slicer settings are irrelevant.
I had a similar problem recently. I switched to a titanium heat break since I apparently have a habit of tightening the aluminum ones a bit too hard, and it was fine for a while but I started getting clogs basically every print at about the 10 minute mark that seemed like heat creep. I couldn't figure out what the deal was since titanium should be even better about heat creep.
It turned out that the machining for the heat breaks might have been too rough I think? Or at least not "perfect" in some way. I had a ton of problems until I "seasoned" them with mineral oil. Basically throw a couple drops in the heat break with it at about 250. Obviously be very careful since it's flammable. You could probably accomplish something similar with an old school filament oiler.
If you have the default nozzle for the Neptune 3, then I believe that the PTFE tube runs right down to the nozzle?
If so, that's probably where the issue is coming from.
Get yourself a bi-metallic heat break and replace the stock one.
They're cheap and easy to replace. The printers that I've had jamming issues with have been fixed by replacing the heat break with an all metal one.
You just have to lower your retraction to 2-3mm or it jams as well.
Looks like the Slice Engineering Copperhead C-E fits the Neptune 3
It sounds like you've gone above and beyond this in terms of cleaning, but have you tried a cold pull?
It might be worth a shot.
Have you checked the health of the extruder stepper motor and really examined the filament path? I've had two weird issues with my direct drive extruder, one was the filament had work a small groove into the metallic tension arm which would catch the filament and cause it to jam. The other issue was a stepper motor that got some debris in it and would bind up intermittently. Not sure if your printer has a bowden setup, but it's something new to check out.
I have a Bowden setup, I'll try checking my extruder and tube setup when I get home, but it's able to extrude filament out of the tube no issues if the hotend isn't attached. However maybe the extruder is not working completely correctly and is having issues with the pressure buildup during actual printing.
What kind of filament are you using? Acetone will not do much for petg and torching it can bake it into a hard mess. Have you tried doing a cold pull?
Found that pla and petg can cause clogs if they get too hot. Is your hotend a fixed block or one of the ones where you need to secure the block while tightening the nozzle? How tight is your extruder? Like the screw that holds it closed, you can strip the heck out of filament which ends up looking like a clog. Have had some filament mushroom in the heatbreak before and that can cause issues.
I've tried multiple filaments with no changes. All have been PLA. Acetone softens PLA enough to make it very easy to clean, I've read multiple times online it won't do anything but literally a 2 minute soak in 100% acetone drastically changes PLA's properties.
I'll try playing with my extrusion tightener again. Ive been printing with it pretty loose, but tightened it when diagnosing this issue because now it clicks when it jams instead of just spinning silently.
I believe its something simple, like heater wire losing contact or stepper driver overheating. After reading your post and even all the comments, I could ask you a lot more questions like:
Where does clog happen? Is it between the nozzle and the heat break? Did you try cold pulls and do you have a picture of filament end? How do you identify a clog? Is it just clicking noise from extruder? How do you fix a clog? By replacing nozzle? How hot is your extruder motor and stepper driver? Do you have a cooling fan on steper driver? Have you ever adjusted stepper driver vref? Did you tighten the nozzle while heated? Did you try tightening more (don't brake it)? Is extruder fan working properly? What retraction settings do you use? Does your bowden tube have any play at both ends? Why dont you PID tune your hotend (its important especially after upgrading hotend)? Did you try printing at higher temp like 210-220C? Did you try extruding without hotend (like disconnecting bowden tube and running filament trough extruder)?
Before you answer the questions, I think you should try just extruding (low speed) at higher temp like 210C until the issue happens, then check how hot is the extruder motor and steper driver, also try pulling out the filament at (lower temp) and inapect it. Inspect the extruder and extruder gear marks on the filament. Would be nice if you report here with pictures
Where does clog happen? Is it between the nozzle and the heat break?
It is either in between the nozzle and heat break, or in the heat break. I'll have to experiment a few more times when I get home, but one time removing the nozzle did not fix the clog, while another time removing the nozzle did fix it.
Did you try cold pulls and do you have a picture of filament end?
Cold pulls, warm pulls, and shoving filament in until the clog clears. All clear it for a while until it eventually clogs again.
How do you identify a clog? Is it just clicking noise from extruder?
Gradual increase in frequency of ticking noise coming from extruder motor (Bowden setup) and decrease of filament extruded until eventual complete clog.
How do you fix a clog? By replacing nozzle?
See above, either pulling it out or pushing it through.
How hot is your extruder motor and stepper driver? Do you have a cooling fan on steper driver? Have you ever adjusted stepper driver vref?
I will have to check temps when I get home. There is no cooler on the extruder. I have not adjusted the Vref (had to look that up), but I originally tried tuning the stepper rotation distance before I knew there was a clogging problem.
Did you tighten the nozzle while heated? Did you try tightening more (don't brake it)?
At this point the hot end has been disassembled, cleaned and reassembled probably close to 50 times in the last 2 weeks. It's been done cold while disassembled, hot on the printer, after the nozzle has been torched from cleaning, you name it. Both nozzle and heat break are as tight as they can be.
Is extruder fan working properly?
Yup
What retraction settings do you use?
The printer clogs even outside of prints, so retraction is not an issue.
Does your bowden tube have any play at both ends?
Nope
Why dont you PID tune your hotend (its important especially after upgrading hotend)? Did you try printing at higher temp like 210-220C?
I had not heard of PID tuning until reading comments today. I might look into it when I get home, but as I've said other places I don't think heat is an issue as reported idle temps are same as the build plate and clogs are able to be fixed by pushing filament through the heated nozzle. Also, filament still oozes from the hot end while clogged. I've tried printing at recommended temp, as well as far below and far above recommended, doesn't change anything.
Did you try extruding without hotend (like disconnecting bowden tube and running filament trough extruder)?
Yes, but not enough to "test" it - what I'll try is disconnecting the heat block, leaving the heat break attached to the printer, heat the nozzle, then try running ~1m of filament through the (cold) heat break. I'll have to report back in a few hours when I get home.
I've read your update in OP, how did it clog in the heat break? Do you have a picture? Can you run the same test without heat break, just extrude cold filament in the air (no bowden tube). That test would show if your extruder is working properly. I still think you might have stepper driver or motor overheating. If the test doesn't fail it would mean you should look into bowden tube/heat break
At this point the hot end has been disassembled, cleaned and reassembled probably close to 50 times in the last 2 weeks. It's been done cold while disassembled, hot on the printer, after the nozzle has been torched from cleaning, you name it. Both nozzle and heat break are as tight as they can be.
Its important to tighten nozzle properly. Tighten it, heat it up, tighten more, done. Both heat break and a nozzle must be clean. It's the only way to achieve a good seal.
What about the printer environment? Has anything changed? Have you moved it? Has the ambient temperature changed even slowly? (I can't print pla in an enclosure during the summer, but I can in winter.) did you add or remove air circulation? Change the ac temp? Anything else external?
Nope, printer has been sat in the same spot (in a loose enclosure) for around a year. I don't recall having issues in the summer last time, and I'm pretty sure they AC was on at least yesterday when I was tinkering with it, I also tried testing outside the enclosure the other day and it was still clogging. I'll make sure the house is fairly chilly while I'm doing further tests today.