bowden tube not staying in extruder head

Viewing 9 posts - 1 through 9 (of 9 total)
  • Author
    Posts
  • #11952
    shackman0
    Participant

    the bowden tube “creeps” out of the extruder head over time, say 1 hour into a print. it’s particularly problematic if the print job has frequent retractions. once the bowden tube escapes from the print head, no further filament is extruded and the print is ruined.

    if i print something that lasts longer than an hour, i have to “baby sit” the printer, pause it on occasion, reseat the bowden tube, and continue the print. two problems with that: 1) makes it impossible to run a print overnight, and 2) continuing creates an imperfection at the point the printer restarts printing.

    hey bcn3d support folks: how do i fix this?

    #11954
    Phill
    Participant
    #11956
    fred_dot_u
    Participant

    Having had exactly that problem, I can tell of the handful of different methods you have available.
    One poster suggested to cut the tube end squarely and apply the adhesive spray to the end for the depth of insertion. I didn’t try that one!
    There’s a thingiverse model for a threaded cap, which requires that you cut with a die the appropriate threads on the bowden tube. It’s difficult to get correctly centered threads on the tube, leaving thin walls. Additionally, if you have to remove the tube, it is necessary to re-calibrate the printer after each assembly.

    I created a modified version of the original model, using less plastic, but it did not remove the other factors from consideration.

    I have a number of sets of feeler gauges. I’ve discovered they are extremely hard steel and destroy drill bits in short order. Should I make this item again, I would use the edge of a right-angle grinder for the bulk of the cuts and a dremel type tool for the fine tuning. This item is a fork of less than 1 mm thickness cut to enable the edges (the tines) to surround the quick release flange and fit underneath, forcing it upward, keeping the bowden tube secure. After destroying the drill bits, I created a plastic model version, also on thingiverse.
    The steel version was inappropriately added to the 1658562 thingiverse entry, while the plastic one is here:

    Yet another version of the plastic clip is located here:

    The last one here appears strangely similar to the one I created, perhaps a bit more refined. Having used the plastic one most extensively, I’ve discovered that the traces of plastic tend to separate after a few uses. That would make it necessary to print spares in reserve, but I tossed mine in the bin and returned to the metal feeler gauge version. I ground a slight taper on the tips of the tines in order to facilitate slipping it under the flange.
    I marked the tube to monitor the creep and found that it has ceased.
    I think a re-design of the system is in order.

    #11963
    shackman0
    Participant

    @Phill thanks! i’ll give those a try and report back here with the results.
    @fred_dot_u i think you’re missing some links.

    #11968
    fred_dot_u
    Participant

    I’m missing more than a few links, but I think you’re referring to the message. I see now that none of them posted. I used to know how to use computers.
    StikDesign initial threaded model
    Fred’s modified version, including butchered feeler gauge metal version (best of all)
    3D printed wedge model, not too durable, but it works
    Soliddo’s version of fred’s plastic wedge, slightly refined.

    #11971
    shackman0
    Participant

    @fred_dot_u ha ha! thanks for the english lesson! you’re right. on 2nd reading, i should have been more clear. i used to know how to use english.

    #11975
    fred_dot_u
    Participant

    Not so much an english lesson as an attempt at humor, which is often difficult to impart via text on a screen.

    #11995
    shackman0
    Participant
    #12009
    fred_dot_u
    Participant

    If you discover after some use that it delaminates on the inner edge of the fork, please post accordingly.

Viewing 9 posts - 1 through 9 (of 9 total)
  • You must be logged in to reply to this topic.