[Dual Extruder v3] Filament Stops Feeding, Ruins Print, Can't get out Easily

I have recently installed and started using the dual extruder with my Taz 6 and I have been having many issues with it. The only time I have been able to get a successful print was with the sample filament and support filament that was given with the shipment. The filament that I have is Polylite PLA and is the same dimensions as the sample filament given. In the beginning of my print today (no support filament, just using one extruder), everything seemed to run correctly, but after laying down multiple layers, it seems that the filament will stop feeding. After this, the print is ruined. I am not sure what I am supposed to do about this issue because after this occurs I cannot get the filament out easily despite heating the nozzle. It seems like I have to open up the extruder and get it out that way. I am cutting the filament the same way that the dual extruder v3 installation guide suggests, but this issue persists. Has anyone had a similar issue with this? If so, how did you solve it? This is getting to be a pain.

Heat creep is horrendous on the dual v3 and PLA. Recently for the first time I’ve had to take apart the head to get the filament out. But first try this if you can still grab onto the filament from the top where it feeds. Heat up the Extruder to about 180, put a card over the front fan that’s attached to the heat sink, you want the heat to travel up a little bit. Remove the screw that pinches the filament that feeds the head. Keep an upward pulling force (doesn’t have to be a lot) on the filament, if the heat travels up enough where the filament is probably stuck on the heater block it should pull right out.

If you don’t have enough filament to pull you may have to disassemble the head. If you do be careful with the wires, they are tightly packed and may be somewhat brittle from the heat, my thermistor wire (blue rope like coating) freyed and started causing a E2 err max temp error.

To remove ABS filament, I usually extrude 5-10mm then retract out of the extruder body. It might work for PLA also. You may need to help it by pushing the filament or pulling to get past the portion that’s been ground out by the gear.

Somewhere within the extruder, the filament path must expand. When heated, the filament swells before it melts. The swelled filament can’t be retracted… it needs to be extruded then retracted.

Hope that helps… or leads you to a solution.

I haven’t had to disassemble my Dual Extruder V3 (yet) but I’ve had some “close calls”, and blocking the front fan saved me.

I decided to be proactive about preventing heat creep and so I printed and installed https://www.thingiverse.com/thing:3213878. You have to be careful with the wires but I was able to use the stock fan with just a bit of wire rerouting. You should print it in the highest temperature filament you have. I printed mine in PETG instead of ABS. If printed in PLA, be careful with using the “block the front fan” technique.

I feel your pain Casey. The lulzbot r & d people must be frustrated as well. I have 2 Taz 6 printers with excactly the same dual extruder config, using the same material, they both get thier gcode files from the same pc and they are side by side in the same room. One of the has printed for 10 days straight without a glitch, the other won’t even make it through the day? I think that maybe it’s a control board issue as I have swapped over tool heads and I thought I had some success, but alas no, same printer different tool head same problem.

The heatsink fan on the dual extruder is garbage. Replace it with this one from Amazon (https://www.amazon.com/gp/product/B072Q3CMRW/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1) I did that and have had no failures or jamming since. You will also need longer bolts for the fan though. 2 M3x70mm and 2 M3x40mm

How long did these issues occur for you? I am looking in to getting that fan, but I just wanted a little bit more information.

I have the dual head and find this interesting the fan you make a link for is 5v I assume the stock fan is 5v also and its just a direct swap… other than the bolt issue…

looked on the shop - spec its 5v will order today thanks for the head up

I have this fan as well. Has improved but not eliminated the heat issues. I also had to take my head apart because one of the extruders was “freewheeling” on the motor shaft. It seems the grub screw had backed out (or was never put in correctly the first place).

I wonder if I am having a heat creep problem with the v2 duel also. Only seems to happen when I print nGen or PLA.

I attached a pic of how the print last night went.

For some reason, the duel head ran for about 3 weeks with no problem, then this weekend it has just been giving me fits. Last night I got one good print, then back to the same problem of the filament not feeding.

Could humidity also be contributing to this? I do dry my plastic, but living in Nebraska… well we have humidity. :smiley:

Very possible! Definitely with PLA. The picture you uploaded looks like nGen filament correct? How long into the print? What’s your printing speed? Are you printing with a 2nd filament in the other extruder? If not I suggest getting the Aerostruder print head with a silicone soc for single filament prints, that print head is flawless!

I can print PLA in my dual extruder for a long time as long as I keep pushing filament through. Once I start printing with 2 filaments it seems that the heat creep gets me on my PLA! The second filament (Ninjaflex) prints at a much hotter temperature (225C) and while its printing the extruder with the PLA cools down a bit (175C) while its on standby while the other filament prints, then heats back up to my PLA printing temperature when its time to print the PLA again. Eventually the heat creep gets to it and it fails. About 2 hours into the print for me, the first hour is PLA, after the first hour it kicks into printing the other filament. However I was printing the PLA at a high temp like 225C, since I throttled it down to 185C I’m beginning to able to get successful dual extrusion prints with PLA and Ninjaflex filament. I also replaced that weak ass fan with a Noctua fan

Pictured is PLA.

Just using the 1 extruder. Number 2 is heated to default stand by temp. I have been using the default temps in Cura 3.6.13

I have found that 40mm/s is a good speed for me. It seems to allow the finer details to show through on some of my other prints and I have just gotten into the habit of that speed… Could I be printing too slow?

Normally fails around the 1.5 hr to 2 hr mark. Yesterday it printed fine. Today, it failed 3 hrs into the print.

Just seems to come and go.

I can confirm that the 1.5 to 2 hour mark is about the time my PLA prints would fail on the Dual Extruder v3. I doubt turning up your speed from 40mm/s will make any real difference, I use the default profile’s speed setting of 60mm/s and still experience failures around the same time you do. Both extruder’s share the same heat sink (a poor design IMO) so what you should do is try making a dummy profile for the other extruder you’re not using. I know there’s a No Material profile but… I’m not quite sure what that profile does cause the printing temperature is set to 240C. Though I guess that doesn’t really matter cause the unused extruder associated with that profile should be in standby which is 150C. But why heat it up to 150C (302F) if you don’t have too! Especially when cooling is a problem!?

Turn on your printer and look at the LCD panel and see what the temperature is at. Set it to that or maybe 5C higher cause if you set it too low it will never cool down to reach your target temperature, plus it will heat up to the target temperature quickly; especially if it only has to go up only 5C or less. It is possible to make a profile with 0 degrees but I don’t recommend it, it will take 2 or 3 minutes to timeout and move on.

Know that some settings on one extruder will affect the value on the other extruder. Extruder1 + Extruder2 / 2. For example, the Build Plate Temperature is a value shared between extruders; a change on one side will affect the value on the other side. Layer Height is also a good example. So be sure to make your dummy profile with the same value of the filament you’ll be printing with for the settings that are shared.

In quick summary in the dummy profile I would set all the printing temperatures to about 30C including the standby temperature. Here’s a good link that explains what those temperature settings mean. https://ultimaker.com/en/resources/52837-material

I get successful PLA prints on the v3 Dual Extruder with a better quality PLA such as that from Hatchbox. Some PLAs are just too soft (mostly no name brand) and absolutely nothing can make those work on the v3 Dual Extruder, and I’ve tried many things to improve the cooling to no avail.

I’m confused. I think NebNorse is talking about heat creep on the Dual V2 and JoeBowler300 is talking about the Dual V3.

While both the V2 and the V3 can suffer from heat creep, the reasons and possible solutions are very different. On the V2, the two extruders are separate each with its own (IMO, inadequate) cooling fan. One solution is documented in https://forum.lulzbot.com/t/dual-extruder-v2-heat-block-fan-upgrade/3366/1

On the V3, the shared heatsink with, IMO, poorly engineered cooling flow, has a solution that works for me at https://www.thingiverse.com/thing:3213878. I was able to get the stock fan to attach with some careful rerouting of the existing wiring. There are also higher CFM 40mm fans that can be used if necessary.

I will print those out, get a few fans and give that a try!

I did get the PLA to print. Dried it out for about 2 days, cooled the printer and it did work. The nGen however is still giving me fits, so I will deferentially try this.

Well hell! I guess I didn’t notice that. :astonished:

So after extensive testing… more than you would want to know. I found my suspected problem and it seems solution.

The dehydrator I was using was getting too hot for the material. If I dry them at a lower temp for 12 hrs, it prints much much better.

I did install the heat sink coolers and that really did help a LOT! Thank you for that tip!