Ultimate Greg's Wade's Geared Extruder - Bowden version w/ PTFE Liner

by elahd Jun 17, 2016
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Hey, I'm facing a weird issue : My filament keeps popping out of hobbed bolt and idler bearing in the middle (or start) of the print, no matter what I do. I tried not screwing idler bolts hard, I tried screwing them hard, same issue.

I have a M6push fit, and the ptfe tube does not go through it. So I put in the extruder another ptfe small tube, but it's loose and moves when wushing filament hard. I don't get how you manage to not have 2 tubes. You don't have push fit ?

I think I found the culpritS :
1) I may not have screwed evenly the 2 idler screws, giving an angle to the idler
2) I have turned m filament spool the other way (free filament on the up side), cause I had too much friction holding filament down (need to print spool adapter)

If you continue running into issues, try the following (in this order):

1) Check that your E steps per mm and max acceleration are well calibrated.

2) Check that retraction settings aren't too aggressive.

3) Make sure that your filament is fresh. In my experience, old, crumbly filament is especially prone to popping out from the extruder's cold end.

4) Increase hotend temperature in 5 degree increments until you're satisfied that the problem is solved (but before you reach the top end of what your printing material will tolerate).

Hi, may I add too that
1) M4 nuts hole (for idler pression) are too big, my nuts are rotating inside. But it's an issue from source model
2) the files section is missing the WadeHerringboneGears.scad

1) Nut diameter varies from manufacturer to manufacturer and model to model. If the holes are too big for you, uncomment and modify the m4_nut_diameter variable in configuration.scad.
2) I didn't make any changes to the gears, so I decided to exclude them from this thing. You can use the gears from the original model.

another issue, but I see it comes from the original : the "The idler hinge support" is cut by a tool, and so can not fill it's role

edit : if cura is set to "exclusive mode"

hi, is this "right" that motor mount holes and hobbed bolt hole are NOT open ? (not cut deep enough ?)

They are cut all the way through. It looks like Thingiverse's 3D viewer is rendering incorrectly. You should see the holes in whichever slicer you're using.

...but this is not the case :/. Here you can see the slicing of the STL file in the download section, with cura. Holes are obstructed

Weird. I haven't looked at this model in a couple of years. I remember it printing just fine, holes and all, but I do see the issues now in OpenSCAD and Cura. Either way, I fixed the issue and updated the thing files. Try the new version.

Ok this is weird.
I previously printed the included one with the bracket and it worked fine, hobbed gear at the right place and everything.

But now i got a enclosure and wanted a wall mounted extruder so i opened up the scad file and removed the bracket and i modified the pushfitting size / thread to fit a 9.5 pushfiting.

Looked great when it came out, pushfitting went in perfect.. But when i placed the hobbed bolt in it i noticed that the hole that the filament comes out of is about 2mm lower than the original one i printed. So the filament hit the hobbed bolt (same bolt btw)

Is this because i have modified the pushfitting size? in the previews the ptfe hole doenst seem to be moving when i modifiy it.

the idler is not flat to the ground ;) you need to fix it

Ugh yeahhhhh.... it's a problem with the original model that I haven't had time to track down in the scad source. Most slicers will allow you to break out the idler and level with the print bed. Have you tried that?

Update 2018-11-23: This is now fixed in the model.

It also looks fine to print it with support that touches the buildplatform.

I've been using the PTFE liner trick on one of my extruders for some time. It works great! All I did with mine was import it in OpenSCAD and make the hole larger. :) +1 for like minds!

Yep! That was my first attempt. I noticed that just making the hole bigger caused problems with alignment: first, the filament ended up 1-2 mm too far from the hobbed bolt and second, the idler -- which is dynamically positioned in OpenSCAD -- was pushed too far outward to accommodate what it interprets as ~4mm thick filament. This design has the filament line up nicely with the bolt while keeping the idler mount at the proper depth.

Fixed all of the jamming problems I ran into with my new bowden setup.