Filament starvation from the guide tube being too long?


I failed a print the other day because of what looks like filament starvation. After looking at things closer, I think the filament “guide” tube is too long and wrapped itself around the almost empty spool.

Can anybody think of a reason why it need to be any longer than what would make it tangent to the outermost winding on a full spool? It only needs to go a quarter of the way around a full spool, as far as I can reason. Thoughts?


Since i had similar problems, i tried it without the tube. And this was about half a year ago, never used the Tube anymore


Hmm…I have been ran onto the problem few times. I will try without a tube that’s a good ideas because all my spool is hanging vertically. I thought using a tube is for guide a filament to a feeder, does it need for other purpose? I don’t think so at the time. Thanks @drmaettu


After the first month of use, I made 2 simple modification to the filament feed scheme to make the filament feeding less problematic. First, took the top cover out and replaced it with a 6mm plywood with an opening for top feeding with a vertical spool stand on top of Flux; second, I took out the first tube section. The distance to the feeding stepper being very short, the tube had no beneficial effect, plus it also caused some friction. That tube section is the same length as the one going to the print-head and it makes a good spare. Since these mods, I rarely have filament feed issues and changing filament is now much simpler.


+1 for not using it with small spools.

I have several filament dry boxes, and I’ll sometimes use it when feeding from those, but they sit above the printer so that tube is maintained mostly vertical.

When feeding from a smaller spool, next to, or in the printer, I do not recall the last time I used the extra tube. It seems more like a failsafe for using exactly sized flux spools from inside the top of the printer, but with anything else it isn’t really necessary as long as your filament is clean and dry.

Any feed issues caused by filament quality problems are going to be discovered at the bowden extruder anyway, and you’re definitely familiar with that.

In fact, the only reason I sometimes use it from the overhead dry boxes is that as spools get past the midpoint of winding, the ‘curl’ in the filament seems a bit tighter so having it run through the tube just helps to straigten it out before it hits the feeder.


Yeah, once the spool is down to the last few layers of filament, the tube is too long and constricts around the reel instead of letting the PLA pull through. I don’t use that tube either as a I have all of my reels on a vertical stand next the printer. I believe it’s purpose was to to be a guide/decurler, but mainly to filter out dust/PLA grit, but I also use the 3D printed filter you’ll see knocking around the forum somewhere here, and I haven’t any any issues that way (much better actually, doesn’t seem to be any knocking from too much friction on the secondary tube either). Before I made the vertical stand though, I just removed the tube, and used the filter instead.


lol, I never installed it in the first place because I thought it was a spare for between the feed and print head >.<


Just out of interest are these problems on the original delta or delta plus? I never received this tube with mine (delta plus) however there seems to be a few pads of PTFE stuck to the machine to ease the spool movement… perhaps this is the fix.


The original delta from Kickstarter came with a feed tube. I don’t know if the new one does or not, but it proved to not be absolutely necessary in my meddling.