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I'm still fairly new to 3D printing; got my Ender 3 V2 for Christmas last year. Recently the tension arm in the stock extruder snapped, so I bought and installed an all-aluminum replacement. My first successful(ish) print since installing it lasted two to three hours before I noticed the filament wasn't feeding. It had softened and clogged the lead-in to the Bowden tube just past the tooth gear. I figure the problem comes from (and what probably broke the original plastic) heat buildup; the new aluminum frame was VERY hot to the touch. I also noticed that the extruder motor was rather hot as well.

So you all know where I am: all I've printed with is PLA at 195 °C. Since changing extruders, I was getting over extrusion and dropped it to 185 °C and increased the retraction from 5 mm to 6.5 mm. The new one doesn't have (easily) adjustable tension, but the tension felt as strong as I had it on my old one, so I left it alone. I currently print within an enclosure, one of Creality's foil-lined ones since my printer is located in the garage (this is more for dust, but for longer prints I felt it was good to have since at the time it was getting very cold at night in the garage).

I don't think it's heat creep, since that meant it went all the way up the Bowden tube. My first guess is the ambient heat inside the enclosure. I am currently trying a new print with the top and side openings folded up to allow airflow. But I welcome more experienced suggestions and input.

Additional info

I think I was getting away with the low temperature (185 °C) because my printing enclosure held heat so well. I'm attempting to print outside the enclosure today to start removing variables to my problem, if it under-extrudes, I'll bump the temperature up again.

Please note that I replaced just the frame.

I wouldn't know how to adjust the voltage [of the Z-stepper] if indeed the [pre-set factory calibration is incorrect and causing the stepper to heat up]. The new tension arm is a bit tighter than I had it set on my old, but I can't imagine it's making enough resistance to overwork the motor without seeing other issues first.

I didn't see any signs of Heat Creep when I pulled out the filament. The only softening I saw was in the direct drive; it had been pushed into a conical shape that plugged the port into the Bowden just past the gears. I'm still leaning towards an issue with the direct drive (is that what it's called? still learning the terms). the aluminum was too hot to touch and I had to wait 10 minutes before I could safely depress the tensioner and pull the filament out. That or the motor is overheating trying to pull Filament through.

The motor driving the filament is on the opposite side of the Teflon tube, mounted to the vertical frame - it is not on the nozzle side of the Teflon tube.

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    $\begingroup$ 185 is very low for printing PLA $\endgroup$
    – Trish
    Mar 12 '21 at 9:30
  • $\begingroup$ @Seradhe: For printing PLA, you don't want an enclosure to hold heat well. As long as it's over 60°C or so, the PLA will continue to deform, ruining the accuracy of your print. It needs to cool quickly to below that temperature, and if the ambient temp is 40° instead of 20°C the cooling will be at half the rate (i.e. (60-40)/(60-20)). $\endgroup$
    – R.. GitHub STOP HELPING ICE
    May 28 '21 at 1:03
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You could still get heat creep with a Bowden tube. It has different characteristics. Instead of jamming up in the direct drive, the filament can melt too far upwards into the heat break where it can refreeze and jam. The characteristic, if you can pull out the filament, is widened filament extending into the heat break.

See Air printing/jamming midway through raft creation

and

What are ways to avoid heat creep?

Adding fans to an enclosure improves the temperature control in the enclosure.

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  • $\begingroup$ How close to the bed? Or. close to any heat source? $\endgroup$
    – Perry Webb
    Mar 13 '21 at 2:50
  • $\begingroup$ Ender 3 V2 has extruder located on one side of gantry (a vertical bar along which the X carriage travels). It is almost touching the Z axis vertical screw from inside of printer's space. You can see it here on the photo. The tube length is about 18 inches (I googled this, cannot measure it today). So this is a standard Bowden-type extruder, not a direct drive extruder. It travels up and down with the gantry, even at the bottom it is rather far from bed... but it is inspiring question indeed. $\endgroup$
    – octopus8
    Mar 13 '21 at 7:30
  • $\begingroup$ I added fans to my enclose, to run when needed. $\endgroup$
    – Perry Webb
    May 28 '21 at 1:07
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Answer created from octopus8's comments. If octopus8 wants to post their own answer, this wiki answer can be deleted.

185 °C is quite ok for several PLAs I have when printing slow.

Honestly, I couldn't believe that the heat can go up the heatsink and Bowden tube to make extruder frame hot. So maybe your extruder's stepper motor is just getting hot heats up all metal elements (or a combination of both)? Did you replace only frame or also the stepper motor? Maybe the voltage is too high? I think voltages might be not calibrated well in factory, because my Z stepper in Ender 3 V2 also is getting really hot since I bought the printer (so far I added radiator, but I plan to regulate this voltage).

The new tension arm is a bit tighter than I had it set on my old, but I can't imagine it's making enough resistance to overwork the motor without seeing other issues first.

I agree with your judgement. Regarding the voltage: first I am not sure if my copy of v4.2.2 mainboard has TMC2208 stepper drivers, or some older HR4988. I would need to determine that first, then find a valid formula for Vref. Actual voltage is tuned using potentiometer next to corner of stepper's small radiator. You can see here an example of this process. One problem is that Ender 3 V2 has the mainboard accessible from the bottom, so I would need something like garage pit to operate...

As you can see, it is important to not touch the screwdriver's metal bar, and anyhow include your body's capacity to this circuit, or you may break things. There are also ceramic screwdrivers - but I already bought two and still my best option is sculpted from 3mm filament. Plastic or ceramic tool will need you to measure voltage separately from turning potentiometer. So the idea of connecting voltmeter to small metal screwdriver is very handy, but you have to be careful to touch only plastic parts.

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Answer taken from Seradhe's comment. If Seradhe posts their own answer, then this wiki answer can be deleted.

Sorry for the long delay, but I wanted to post a follow up to conclude this.

I printed outside of my enclosure with no problem. Best guess is that the sealed enclosure wasn't bleeding off heat very well, and the aluminum feeder (being aluminum) was just soaking up the heat non-stop. Fine for short prints but anything over three hours it would get hot enough to soften the filament. I'm currently printing housings for some extra PC fans I have and framing in a vent system to keep it from getting too hot in the future

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I had this problem when I switched to the aluminum dual gear extruder. The spring was too strong and was crushing the filament out of its round shape into more of an oval profile as it fed into the Bowden tube. This caused excess friction in the Bowden tube, which stressed the extruder stepper motor and caused it to heat up, which transferred through to the aluminum dual drive. This in turn softened the filament in the drive and cause it to lose even more shape, increasing the friction in the tube and further stressing the stepper in a self-perpetuating cycle.

No print lasted more than a couple of hours before the filament jammed in the extruder and I was air printing. The solution was to remove the stronger yellow spring and replace it with the weaker bare metal spring that came with the stock extruder. It's not strong enough to distort the filament and problem solved.

If you are using the stock extruder then the source of friction maybe somewhere else in the filament feed chain.

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    – agarza
    Nov 20 '21 at 1:11

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