Bowden Tube popping out (rostock v2, e3d, bondtech)



  • I am using a Rostock Max V2 with an E3D extruder and Bondtech QR filament driver. I am having random issues with the bowden tube popping out of the Bondtech Mating Part; I cannot seem to correlate the incidents with any particular action of the printer at the time the tube pops out. I have replaced the Mating Part (filament slips into it and is gripped), the bowden tube, and filament (both PLA and PETG) with no improvement. I have tried different tightness's of the thumb screw on the bondtech with no improvement. i have tried running without the "clips" for the mating device and with the "clips" in the mating device with no improvement. i am noticing a rather high (to me) band of temperatures around my "goal" temperature - if i want 227, i get between 220 and 230 degrees. i am used to maybe +/-3 degrees on other printers and don't know what the E3D with your software should give me. i have replaced the nozzle several times and that might have helped but i don't have enough data to make me believe that - i have tried .5 and .6mm nozzles brand new. when i do a pull test on the filament (both ends - driver and extruder) the filament is held well after i insert the filament deep into each device - what i am tying to say is i am WELL past the little teeth in the mating device and not right at the end of the bowden tube... let me simply with HELP - this is a pain in the xxx and i can be 12 hours into a 15 hour print and it can happen. has anyone else experienced this issue and more importantly defeated it....?

    dennis



  • Moderator

    The bowden tube should not be coming out of the fitting under any circumstances. If it is, then something must be wrong with either the tube or the fitting itself. I'm suprised you are still having issues after replacing both the tube and the fitting. Are you using the built in fitting on the top of the Bondtech or are you using a groove mount bowden adapter on the bottom? Are you using the bowden tube that came with the Rostock or the one provided by E3D? I believe they may be slightly different diameters.



  • i am using a bowden tube i bought on amazon. they all seem to have the same specs? i have replaced the "grabber' fitting on the bondtech twice and have the same problem. i am beginning to believe my temps are not being managed right by the rostock software? i am seeing dips to 9C less than my target temp and 3C more than my target temp. i believe i am having my bowden popping out problem when the temp drops too low and the force required to extrude exceeds the ability for the "grabber" fitting to hold that much force on the tube. i talked to matterhackers yesterday and discussed this and they didn't have a proposed solution. i am recording data from the screen (high/low temps for each heating cycle) and will plot those. i wish i had some control over the temp "window" i want vs just a single target temperature. baffled in calif.

    dennis



  • one more thing.... i tried using brute force to pull my bowden tube out of the "grabber" fitting before i put on a new bowden tube and it was VERY hard to pull it out - the "grabber" fitting was working just fine. somehow, i am generating way too much back pressure force from the extruder nozzle - it seems to me that it is temp related. it's a brand new nozzle. it's getting down to where the only variable i can point to is temperature....

    dennis



  • could i have my thumbscrew tightened down too much on the bondtech? if the back pressure from the nozzle gets too high i want the gears to slip on the filiament rather than having such a good grip on the filament that they push the bowden tube out..... i can't find any instructions anywhere on how to set that thumbwheel. right now i have it REALLY tightened down - maybe that's the problem....?

    dennis



  • I had a similar issue occurring. It was frustrating on long prints. The problem has been resolved for me and I think it was several issues occurring for me. I tried many things to resolve it including new Bowden tube types as well as the "grabber"

    One was to much pressure building up within the extruder. Reducing the flow control can help here. When your temp drops you may be experiencing this. Have you tested your thermistor and are you sure you have the right thermistor defined?

    The second for me was the Bowden tube did not have much slack for prints that were at the extreme of the radius. This caused it to slowly work its way out over time in long prints. Using a longer Bowden tube help resolve that.


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