Why is filament building up on the nozzle during a print?
Follow up to my previous post, I cleaned up the entire Heat Block, using a brass brush at a high level, after taking apart everything. Put it back together, and print a sample print.
The print was ok, but there was a small "black" blob and black specs that showed up on there, see images here. Printed on 60 deg. bed and 210 deg. nozzle, with PLA. It was easy to pull of that big chunk using pliers, but what if it had shown up in one of the middle layers? What would be the cause of this?
Second, here is what my extruder, nozzle, and heat block looked like after the whole print had finished, and picture was taken hours after the printer had been turned off. There is a huge buildup of the blue PLA right on the nozzle. Before all of this, I never had a buildup like this. Why is this happening, and what can I do to fix this?
RE: Why is filament building up on the nozzle during a print?
What brand and size nozzle? Some after market ones are not too good on finish.
If you reassembled the hot end, make sure you tightened the nozzle correctly. It should not be flush. Flush == leaks around nozzle.
See:
RE: Why is filament building up on the nozzle during a print?
This is the original hotend and nozzle that came with the printer. When the printer clogged, it was with a E3D 0.25 nozzle, so I went back to the 0.4 nozzle that came with.
The nozzle is as close to the hotend as possible, tightened it completely. But there is some distance between the heat break and hotend. Not sure if that is supposed to be there.
RE: Why is filament building up on the nozzle during a print?
Do NOT tighten the nozzle to the hotend. That will leak.
Follow the guide I listed.
RE: Why is filament building up on the nozzle during a print?
No wonder you have plastic leaking. ‘Sealing’ the nozzle against the heat block doesn’t, seal that is. The seal is achieved by the inside end of the nozzle against the bottom of the heat break. The heat block acts as a very long nut allowing you to torque them together.
if you don’t tighten to spec and do so at full temperature then plastic WILL work it’s way down the threads and out around the nozzle and on to your prints and all over your heat block.
following that e3d guide to the letter step by step is the best way to make sure you have assembled everything correctly.
RE: Why is filament building up on the nozzle during a print?
OK, I can do that, following the guide.
One question, how did the heat block become lose from the heat break at all? The printer was perfectly fine until 2 weeks ago. Just trying to understand how this happens.
RE: Why is filament building up on the nozzle during a print?
One question, how did the heat block become lose from the heat break at all? The printer was perfectly fine until 2 weeks ago. Just trying to understand how this happens.
By not following the E3D guide when changing nozzles.
RE: Why is filament building up on the nozzle during a print?
I keep reading to not tighten the nozzle but leave a gap when reassembling. Is there an actual gap that is supposed to be there (i.e. 0.02mm or 3mm or ???)? Is this something measurable or just everyone guessing at it and changing it if there is seepage? I would think that if there is a number for the gap, it could be measured and documented.
I have incorrectly tightened my nozzle, then adjusted it so I'm not getting this leekage but I don't know if I've messed up something inside. I had a jam the other day and after getting it clear, I've got the seepage again. I have a "gap" but may have messed up something in the meantime. Is this a case where it would be in my best interest to take the hotend apart and replace parts or look at replacing the whole unit?
RE: Why is filament building up on the nozzle during a print?
You also get referred to the E3D Guide. It is not difficult, but you must leave a gap, tighten the heat break against the nozzle, heat it up, and tighten again.
Don't follow my words - follow the guide.
I doubt if you need to replace anything. Just do it right. And never throw parts at a problem, hoping it fixes something.
RE: Why is filament building up on the nozzle during a print?
Ok. So I followed the guide and redid the nozzle so there was a 1-turn gap between the heatbreak and the nozzle itself. Did the calibration, and after the print there was still significant PLA clog on the nozzle.
I did not open up the heat block, just the nozzle. according to the guide. Is opening up the heat block and heat break the only option now?
RE: Why is filament building up on the nozzle during a print?
Did you heat up the nozzle and tighten it against the heatbreak while hot, as the guide shows?
Maybe some leftover filament leaking out around the nozzle? If that is the case, it should taper off.
Reading your reply again - if you did not get far enough into it to screw in the heatbreak more, it won't work.
It actually has to be screwed in to contact the nozzle.
RE: Why is filament building up on the nozzle during a print?
I keep reading to not tighten the nozzle but leave a gap when reassembling. Is there an actual gap that is supposed to be there (i.e. 0.02mm or 3mm or ???)? Is this something measurable or just everyone guessing at it and changing it if there is seepage? I would think that if there is a number for the gap, it could be measured and documented.
I have incorrectly tightened my nozzle, then adjusted it so I'm not getting this leekage but I don't know if I've messed up something inside. I had a jam the other day and after getting it clear, I've got the seepage again. I have a "gap" but may have messed up something in the meantime. Is this a case where it would be in my best interest to take the hotend apart and replace parts or look at replacing the whole unit?
As far as I know there isn't a number; just the instruction to screw the nozzle in until it seats, then back it out 1/4 to 1/2 turn (i.e., 1/3 turn). It should look like this at the end of the step:
And after inserting the heat break:
https://wiki.e3d-online.com/E3D-v6_Assembly
RE: Why is filament building up on the nozzle during a print?
Ok. So I followed the guide and redid the nozzle so there was a 1-turn gap between the heatbreak and the nozzle itself. Did the calibration, and after the print there was still significant PLA clog on the nozzle.
I did not open up the heat block, just the nozzle. according to the guide. Is opening up the heat block and heat break the only option now?
6.2.5
Unfortunately, you've not followed the instructions and will have issues because of it.
... That or perhaps you are misidentifying parts.
RE: Why is filament building up on the nozzle during a print?
Ok. I got to opening up the heat sink from the heater block. I cleaned up all the clog in the screw attached to the heat-break (I think from the guide and image above, its the heat-break) using a brass brush, but its stuck so tightly into the heatbreak that it won't unscrew or come out.
I have highlighted in red in the pictures here. Should I continue with the rest of the process without unattaching the heatbreak from the heatsink? Pictures here.
RE: Why is filament building up on the nozzle during a print?
Some notes on this:
- The heat break can be screwed by hand tightly into the heat sink.
- The gap between the nozzle and heat block isn't a magic value of any sort. The reason you want that gap is to ensure that the heat break and nozzle are tightened against each other. The gap just ensures you're not tightening the nozzle against the block. As was noted, the block is basically just a nut at this point.
- You have to do the final tightening of the heat break to nozzle at high temperature to get a good seal.
- If you do have a leak and the resulting mess, there's a good chance that you've got filament up in the threads. You need to clean the exterior of everything, but also clear the threads. I found that heating the block up and running the heatbreak entirely through it a few times allowed me to clear the threads. After that, inserting the nozzle, backing it off for the gap and then tightening in the heatbreak was painless.
- Letting everything sit at temp for a while before putting the hotend back in the printer helps make leftover filament on the outer surfaces easier to remove and reduces the odds of blackened crumbs falling into prints.
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RE: Why is filament building up on the nozzle during a print?
Your nozzle is definitely leaking. While you fix it as highlighted by Bostro e.a. make sure you get a tube of thermal compound (e.g. Arctic MX-4) and apply it to the thread of both your heartbreak and your nozzle. Without thermal paste the nozzle temperature may go crazy on you and you don't want that.
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RE: Why is filament building up on the nozzle during a print?
You do NOT use paste on the nozzle or heat break at the heater block: only on the heat break in the heat sink. The paste is rated 100c, not 300c.
RE: Why is filament building up on the nozzle during a print?
ps: Here's AS-5 (4 has no temp spec, so it's probably less than this material): http://www.arcticsilver.com/as5.htm
yep: 135c peak (short term - minutes): http://www.arcticsilver.com/matrix.htm
RE: Why is filament building up on the nozzle during a print?
You do NOT use paste on the nozzle or heat break at the heater block: only on the heat break in the heat sink. The paste is rated 100c, not 300c.
Oh, I stand corrected, you're right. My bad. Thank you for the comment.
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RE: Why is filament building up on the nozzle during a print?
Coppaslip can be used on the nozzle threads, but only a tiny amount and you have to place a paper towel underneath when you first heat the nozzle as the grease component will run out leaving the copper behind in the threads.
Normal people believe that if it ain’t broke, don’t fix it. Engineers believe that if it ain’t broke, it doesn’t have enough features yet.