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ED3v6 PLA heat creep and what are your flow rates?

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Hi. So I´ve been experiencing som blockages when printing PLA with my E3Dv6 hotend om my i3.

So basically I think it´s heat creep, I ususally have my temps at about 205C when ptinting but have noticed that slower feed rates have caused blockages. For instance, I notice my hotend start to tighten up when printing 0.1mm layers and today when spiralizing a vase at 0.2mm/30mm feed rate. I assume that the PLA volume/second is a litte too low so heat creeps up out of the heat block and expand the plastic causing a jam.

I´ll go down in temps (195-200C?) but on to my question. First, do you think my analysis is correct? And what is the lowest volume/second of plastic that you comfortably print at to avoid heat creep? Or do you just keep the melting temp low?

/Stefan

Did you ever solve this issue? I'm getting very similar symptoms on a Printrbot modded to accept the E3D v6.

Well, I did!

The solution for me was to reduce retraction to 1mm at 40mm/s. Any more retraction caused problems, and Ive never had an issue since I changed it and no problems with stringing either.

Regarding temps I now use 210C on all my PLA prints with great effect. When I think about it, I havent had a single problem for hundreds of hours of print time.

/Stefan

I think running hotter and printing faster is a great benefit to keep the heat creep down. I use 0.5mm retraction distance and 220c for my e3d v6 running makergeeks pla usually. Speed set to 45mm/s overall, 50% speed first layers. Also, make damn sure that your extruder is really gripping the filament, like REALLY gripping it. My gear set might be different but it's a good rule of thumb to keep it tight :P

Hi,

Have you read http://wiki.e3d-online.com/wiki/E3D-v6_Troubleshooting ?

Note: A common issue is massively excessive retraction distances. In direct configurations retraction of 0.5 to 2mm is all that should be needed for ooze-free prints. We use around 0.6mm for ABS that oozes very little, and 2mm for the very floppy flexible filaments that like to ooze a great deal and need a good tug to pull back the soft filament from the melt zone. For PLA we stick with retraction settings no higher than 0.8mm.

Thanks for the wiki link! :)

After previous jams I came to the conlusion myself that retraction had to play a part in it... So I´ve reduced retraction to 0.7mm for PLA, 1mm and up caused problems as you describe. I couldn´t see any adverse effects of the reduced retraction distance either... Retraction plays a big part in it, but not in this particular case since my print was a spiralized vase (with no retraction)

check your tension on your extruder is tight enough pla is softer than abs so you need tighter tension... 200 to 210 is good for pla with a bed temp of 60 or no heated bed..

if clogs persist pull your hot end apart use a torch not a lighter lighter is a dirty flame a cigar torch etc works good heat it up and stick a super small oject you know wont break off in the hole to clear it out you might have to replace your teflon tube its cheap on ebay

Extruder tension is not a problem, what I run into instead if I REALLY push it (much more flow than needed in any print) I get stepper driver overheating. But that´s normal I guess...

Check your 30mm fan airflow and consider upgrading to a new fan. Every single time I have ever had heat creep on this setup it has been a fan issue. They don't last forever.

I think I´ll heed your advice and replace the fan. Mostly because more hot end cooling can´t be bad, and the fact that the original 30mm fan is quite noisy!

I´ll get a new 40mm fan today and print out this fan mount for it :)

http://www.thingiverse.com/thing:506958

E3D V6 40mm Fan Mount

I read the original fan has a throughput of 4.1 cfm, I can go with a 40mm fan that has 6.1 or 8.2 cfm respectively. So a 50% or 100% bump in airflow. I think I´ll go for 100% :)

try using a oiler, pla works best with oiler

Won´t the oil affect print quality in some way?

So far it didnt affect anything in my prints (cross finger) but all the issues with PLA jamming just disappears with oiler.

Hi Stefan, I suppose that the problem is exactly what you say:"heat creeps up out of the heat block and expand the plastic causing a jam".
To avoid this problem you can try increasing the cooling of the hotend, trying to block the heat to come up. Try to use a more powerfull fan.
Do you have an original E3Dv6 or a clone? Is the light or the full version?
Sorry I read just now that you have PTFE inside, so it's the light version...

No actually I have the original, full version. The PTFE tube goes down a bit, but the heat break is fully metal. I also use the original small fan and blue shroud.

I bought the E3Dv6 just because I had a lot of clogs with my original hot end, and it has worked very well. But I notice that I often approach the limit of the heat dissipation for some reason, when I print at 0.1mm and normal feed rates it begins to studder sometimes. I´ve had clogs, and could remove them only by heating up the hotend and pulling upwards with a pair of pliers. Then I could see a thinckening of the filament just at the end. I assume that fatter, expanded part develops just above the metal heat break (ie in the PTFE tube)

Thanks. The problem is not too fast extrusion, the hot end can push 15mm^3/s if I want it too. No, it´s rather a problem that occurs a lower flow rates. So there must be a problem with heat building up above the heat break, expanding the plastic. I´ll replace the PTFE tube with a fresh one today, and see if that helps.

Too fast extrusion can also be a reason - trying to squeeze more filament through the nozzle than parameters (printing speed/temperature/layer height) allow.

Some cheap Chinese MK8 extruders seem to have too short a PTFE tube inside the throat pipe (between feeder and nozzle). This was the case with mine, resulting in the tube moving downwards over time, leaving too much space between feeder and PTFE tube, where filament could curl up and block. My blocking problems were gone when I simply inserted a longer end of PTFE tube.
205° is well within reasonable bounds for PLA, and should cause jams or blockages with correctly configured hotend.

I meant to say "... and shouldn't cause jams or blockages with correctly configured hotend."