Hi everyone, a really hard problem lead me to this group, hope you can give me a direction with this.
I’m building a custom machine with double x carriages.
Everything works fine except the extruders, both of then randomly grinds the filament into the ptfe tubing during printing. This is my first dance with 1,75 filament and I can’t figure out how can it stuck this easily.
I attach a few photos, I know the extruders look horrible but it shouldn’t matter, the filament is supported really close tho the gear by the tubing and manually I can extrude indefinitely without a problem.
I turned of retractions completely but the problem persists.
The hotends are Chinese knockoff E3D vulcanos, I cleaned them, off the filament goes trough them freely by hand, yet they stuck when printing. Temperature is 180 centigrade, should be good because at 185 it starts to stringing.
I’m open for any suggestions, after one week of intense fiddling with the setting and the mechanism I’m out of ideas.
+Peter van der Walt ok that’s definitely an option but, more power won’t solve my problem. I don’t need extra grip on the filament. If this extruder can bend the cold pla insude the tubing then bending it harder won’t solve the issue.
Hi @1111185 ,
I think your problem is your PTFE tube.
What is the Inner and Outer diameter of the tube?
If the filament is too loose inside the tube, it will bind, and twist within the tube.
The gap between the tube and gear would also be concerning. That should be minimal. Your filament might jam at that point.
I can’t really see from the photos, but I understand that this is your typical Bowden setup, right?
Are you driving the filament from 2 points? Why the extruder on the Hotend side?
You should be using a 4mm OD and 2mm ID PTFE tube. This looks like the filament is binding inside the PTFE.
Definitely a jam somewhere. Usually this is at the hotend, however as @Panayiotis_Savva has said, the only other possibility is your ptfe. Have you tried feeding the filament without the tube?
Also it looks like the tube feeding into the hotend from the extruder appears to be pinched - another possible jam point?
How long is the ptfe tube? And dubble check the heatbrakes, knockoffs often get the ptfe tube insert depth wrong…
@1111185 From the photo where the extruder is open it almost looks like the PTFE tube is a bit too high, is there any chance that the bearing presses onto the PTFE tube and compress it leading to increased resistance?
Try to decrease the pressure of the idler, it looks like you are crushing the filament. Don’t pay attention to +Peter van der Walt , I have absolutely no problems with a Wade-type extruder, I’ve been using one for years, never a problem.
@Chengster_N I second the pinch sighting. Teflon tubing I have doesn’t deform that easily!
+Peter van der Walt oh shush hahaha… I run a Wade’s geared hinged Greg’s accessible herringbone’d etc etc extruder and love it. Also, the first iteration was published in 2010!
Looking at the depth of indentation on your filament it’s too deep which assumes you have too much pinching force to pull the filament (too much resistance) which leads to slower extrusion and cause heat creep through the filament (supposedly, cold filament in, hot filament out, too slow and heat goes up and the cold filament gets hot too), also the teflon tube are pinched creating more resistance
I think the close-up of your lower tube says it is too big, maybe for 3mm filament and it is being pinched.
Also watch out for filament deformation of the hobbed bold, if it gets too wide it will also increase the friction inside the bowden tube.
@Nathan_Walkner hmmm…at first I was thinking a bowden setup. It is not one. What the bleep is with the flaring out of the end of that tube then??? Is it being clamped down on by the idler to where it looks like a pancake???
Thanks for the help guys, the problem was the pinching of the PTFE tubing. Last week i started testing with a much shorter tube, it didn’t worked at all, then I switched to longer ones that you see on the pictures, and it was better but still not reliable. I completely missed the middle ground, now it’s working like a charm. I’m making a timelapse right now, I share it as soon as finished. Thanks a lot!!
There was a few question about this, it’s belt extruder, works just like the geared ones, but much quieter and with no backlash. The extra ptfe that comes to the two x carriages, is just serve as a filament guide from the spool, through the energy chains to the extruder. After thorough testing the machine will be covered to function as a heated chamber.
wow thanks @Nathan_Walkner actually it is my BSc thesis work in enginerring.
Hi Dani. If I see it right you use Herz filaments. With similar chinese hotends and thermistors that pla works for me best around 220-230 c. Most likely it’s not a real and accurate temperature, I just wanted to give a heads up for this filament-hotend combo 
@Janos_Vilmos Yes it’s Herz filament, I’m using it for a year or so now, and I always used 180-185 for pla and 225 for abs. Not sure that my thermistor setting is right in the firmware. I use Marlin and in the termistor settings “1” is selected wich is “100k thermistor -best choice for Epcos 100k (4,7k pullup)” at least this is what it says. I experimented with the others but seamingli there is no difference.