What causes my Bowden tube to melt on the side?

  • I run a 3D printer farm and I have to replace my Bowden tubes on the printers after about a month or two of use(roughly 1000 hours of use). The Bowden tubes continually melt on the side of the tube very near to where it pushes against the nozzle. I am running Ender 3 Pros and I run at about 205 °C with PLA. The Bowden tubes I have are some I found on Amazon and they are not Capricorn tubes.

    Note how the hole is very near the base of the tube closest to the nozzle

    EDIT1: I have added more pictures below of a new failure. This time you can see the marks of the teeth of the coupler a good inch below the failure point.
    New photo of tube 1
    New photo of tube 2
    New photo of tube 3
    New potho of tube 4

    Melting is virtually impossible, that happens at 327 °C. To me this looks more like wear.

    Hmm, so you're saying that wear caused a tear in the tube?

    I'm saying that it cannot be melting caused by heat of printing PLA :) It *looks* as if it is wear. What other failure modes are possible?

  • After a lot of hard work and months of replacing and inspecting this issue I realized what's going on. The bowden tube gets soft as it gets hotter and hotter which allows the filament which is being extruded and retracted at a high speed to wear down the side of the tube. After some time the tube gets stretched out and it will eventually tear and that is seens as the hole in the pictures I provided. The solution to this problem is to upgrade to an all metal hotend, instate less aggressive retraction settings (which is what I did), or closely monitor your prints and replace your bowden tubing when it does eventually get damaged (which I also do).

    That may have sidestepped your problem but it's not "the solution" and has lots of tradeoffs. It sounds like the underlying problem was a fake Capricorn that's not even really PTFE.

    @R..GitHubSTOPHELPINGICE I'm afraid I purchased the Capricorn PTFE from Amazon so I would assume it is real Capricorn tubing however, the detail about the PTFE getting soft as it gets hotter is information I got directly from Capricorns website so I am unsure as to why you think it's not real PTFE. I would like to point out that this kind of wear on the tubing is after hundreds of hours of printing so I am not sure what you mean by "lots of trade offs" I have found that less aggressive retraction has decreased my print times.

    That's why it's called a tradeoff. Faster prints, but wrong extrusion (material oozed in wrong place) leading to weak and ugly parts. Other tradeoffs too.

    You assume that there is material oozing but there is no such thing. I assure you I never said that I was getting weak and ugly parts after this solution. I would appreciate it if you could elaborate on these other trade-offs because this solution I presented is working quite well for me and the 20 machines I run it on.

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Content dated before 7/24/2021 11:53 AM