Try moving the filament to your right nozzle and doing the same print. It fails for me after the first few layers.
So i was intrigued so i did a quick test.
Added thermo-paste to one of my Dual extruder nozzle assemblies.
Raised the temp up to 200c and then told it to change the temp to 0c.
I timed how long it took to go from 200c-100c with the cooling fan on.
Here are the results 200c to 100c
.4mm Hardened Steel Nozzle 3:42
.2mm Brass Nozzle 3:30
.4mm Brass Nozzle 3:33
.4mm Brass Nozzle With Thermo-paste 3:20
Not scientific at any level. Just some quick observations. Interpret the data as you see fit.
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Hmm, so it cooled down faster eh? That sounds like it would have a noticable impact on things then, yeah. Thanks for sharing
yup just what i would expect it to do. didnāt know how much it would change the rate so i thought i would just test it rather then try and predict it.
I āthinkā it helps but i really didnāt have the issues others have seam to be having. But I thought. Why not I have the parts, people wanted to know. Couldnāt hurt to try it. thermo-paste was basically 5 ft from the machine. So no excuse.
Just needed to stop a 15 hrs print after a bit more than 5 hrs because of right nozzle clog 
Was hoping that I was a winner, seems not. Will apply thermal grease and run the job again, will report backā¦
A bit frustrated.
EDIT: Just did a bit of post mortem: My filament is broadened to 2 mm over a stretch of 39 mm! This is about the length of the heat break, so I suppose it is heat creep. Now I wanted to disassemble my hotend to apply thermal grease, but I fail to pull the heat break from the heat sinkā¦ @mswietlicki is there a trick? I unscrewed the grub screw, but using my fingers I canāt pull the heatbreak out. Iām reluctant to apply more forceā¦
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Take the hot end out. There is a set screw (small bit works). It should slide out. The connector on the back isnāt very tight for the wires.
It will literally fall out. Watch the ptfe tube.
Iām not quite sure how to apply the paste. I bought some nice stuff; just need a moment to apply it.
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Huh, did exactly that (i.e. remove the set screw), but my heat break is stuck like hell, even applying all force I dared without using a tool did not move itā¦ Which is a bit strange, since Iād infer very good contact with the heatsinkā¦ May of course be that some molten plastic got in the gap and now āgluesā the heat break to the heatsinkā¦ Perhaps I need to do a hot removal.
Since my failed print was dual color, I unloaded the filament from the left nozzle also, and it does not show the widening. However, the comparison is not fair, since color two had not much to do, it is only a tiny addition in black to something white elsewiseā¦
My plan: Iāll swap left and right hotend and redo the print, again using the right nozzle. If it fails, it might mean one of the following:
- My new white filament is crap (not impossibleā¦)
- The heat sink cooling is worse on the right side (I seem to see more reports of the right hotend failing then the leftā¦ and the now left, to-be right hotend did a nearly 7 hrs print with no issues)
- Something completely different
Can only report back next weekend, will not be able to restart the print before Fridayā¦ Will keep you posted.
EDIT: Just unscrewed the set/grub screw of the other hotend, and I can indeed easily remove the heat break. Will try the other againā¦
EDITEDIT: Now it came apart. And it is matching the 39 mm very wellā¦ Nozzle tip to heat break end is 43 mmā¦ Time for thermal grease! Guess Iāll leave the right nozzle on the right side after all
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@Mads0100 Is right. You should only need to loosen this 1 grabbing screw (and cable connector) and it should slide out easily.
As to how to apply the paste I would just put thin (0.2mm maybe) layer all around outside of the shaft of the heat break. Slowly slide it back in and remove excess with a towel.
PS: Iām also testing modified design of āthe wedgeā that seems to hold wheels closer together. I will post it here after Iām done.
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Thatās what I came up with too. I eliminated filament by doing the same single nozzle print with everything the same between the prints other than selecting left or right.
Gorgeous print off the left nozzle; failure after time with the right. First layers were good of course.
Should be fun.
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So that made me think: What is actually the difference between the left and right nozzle? The only one that strikes me is that the right nozzle is a few millimeters lower when printing, due to the articulating design. But that can indeed make the difference: Since Snapmaker designed the airflow so that it sucks warm air out of the housing, air comes in from wherever it can. From tiny strands of filament that get sucked into the housing I can see that a lot of air comes in from the bottom of the printhead, and that air has passed the heated bed, the hot plastic and the heater blocks of the hotend, so it will already be somewhat warm. And this air is now sucked across the heat sink. For the right nozzle, sitting lower, this effect is more pronounced. It may well be that this diminishes the cooling effect enough for having āheat creepā.
Question is: Will thermal paste be a sufficient solution? From dismantling my hotend Iād say it sits already pretty tight, and when heat makes the metal expand, Iād guess itās really a tight fit and heat dissipation should not be too bad. Will thermal grease improve that? Potentially yes, as it does on top of a CPU to its heatsink. Since the heat problem seems to be a borderline case, the thermal paste might be just what it needs to cross that borderā¦
I guess a more robust solution would be to design something that blocks air from being sucked in from the bottom of the toolheadā¦ Will think about this.
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I used exactly that one, but later learned that this might be even better:
Even better thermal conductivity, and stable to up to 850Ā°C!
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Thats the one I purchased the first time. Pretty good stuff.
I did some tests today with same gcode, one hotend and some environment changes.
Nozzle left:
Enclosure closed, Module closed: successfully printed
Enclosure opened, Module closed: successfully printed
Enclosure closed, Module opened: successfully printed
Enclosure opened, Module opened: successfully printed
Nozzle right:
Enclosure closed, Module closed: clogged after 10min
Enclosure opened, Module closed: successfully printed
Enclosure closed, Module opened: clogged after 40min
Enclosure opened, Module opened: successfully printed
So with my a150t I just have problems with my right hotend. And just with closed enclosure. So i think it is some heat problem. No modifications made so far.
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Interesting detail: They just published for Artisan a Q&A and a Modās Google Doc:
In the Modifications doc is a modification to add a heatsink fan to the DXā¦
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That would explain the leave the door open and use a fan followed by the use thermal paste.
Probably an opportunity to fix the latching issue too.
My guess is theyāll offer a new DX at 50% if they follow their previous updates.
Would the heat creep cause flow rates to get wonky, in the negative?
I have been having problems with the left extruder. Printing smaller objects is typically fine, but longer prints are having this weird issue where the layers arent really fusing together. I think it relates to flow rate.
On small prints with esteps calibrated, the wall thickness of a calibration print is coming out .43/.44 vs the .4, which is not a big deal, just adjust the flow rate. but if the print is longer, the flow rate is insufficent, even removing the flow rate adjusment.
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Hmm, good question. A bit of thinking on that: The insufficient cooling of the heat break lets the filament broaden more and more, starting from the heater block side, creeping up over time. One effect will certainly be that the friction of the filament against the walls will increase. In the end this leads to the nozzle clog, friction being so high that the feeder cannot push the filament any further, but instead grinds it down. In that sense ānozzle clogā is even misleading, since not the nozzle is obstructed, but the filament itself becomes the obstruction. But as the process of heat creep and filament thickening is a gradual one, I can well imagine that the feeder will also gradually start to slip, still being able to deliver some filament advance, but more and more inefficiencies coming in over time.
All just guessing of course, bt sounds plausible to me.
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For me thermal grease did not solve it. Same print that failed after 5h now failed after 2h, extrusion stopped. Iāll a) contact support, and b) build a windshield to stop warm air from being sucked in from belowā¦
EDIT: and c) first try do do the print with the left extruder - I yet cannot rule out the filament, itās not the best I ever had.
Also with open doors of enclosure and print head?