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[Solved] Bowden tube won't stay in push-connect fitting  

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bmorgenthaler
(@bmorgenthaler)
Eminent Member
Bowden tube won't stay in push-connect fitting

So I picked up the Bondtech extruder/heatbreak combo and installed them and while I was at it put in a single bowden tube setup.  Everything was working well with PETG but when I switched over to PLA major problems. I tried most of the suggestions in the post on extrusion issues and decided to go back to the stock heatbreak. That's when I started having problems with the bowden tube.

As you can see in the attached picture it doesn't want to stay down when I start printing (the initial Z calibration from the onboard menu), it doesn't have an issue with purging.

I've tried two different connectors, a drilled out PC4-M8 and a PC4-M10 with adapter and two different bowden tubes, basic PTFE and a Capricorn one.  Anyone have any ideas?

Mini+ with FW:4.3.3RC1, Bondtech Extruder, drilled out PC4-M8 couplers, 1 piece Capricorn bowden....
Posted : 24/09/2021 6:09 pm
bmorgenthaler
(@bmorgenthaler)
Eminent Member
Topic starter answered:
Where did my picture go?

Mini+ with FW:4.3.3RC1, Bondtech Extruder, drilled out PC4-M8 couplers, 1 piece Capricorn bowden....
Posted : 24/09/2021 6:30 pm
bmorgenthaler
(@bmorgenthaler)
Eminent Member
Topic starter answered:
RE: Fixed it

Wow! 120 degree chamfer is important, I pulled my ptfe out and recut the chamfer and took off a bit more than previously, reinserted and everything is working now.

Mini+ with FW:4.3.3RC1, Bondtech Extruder, drilled out PC4-M8 couplers, 1 piece Capricorn bowden....
Posted : 27/09/2021 12:24 am
fuchsr
(@fuchsr)
Noble Member

Great to hear you made it work. I was originally going to suggest that it may not be the chamfer because I use PC4-M8 connectors on my minis but never bothered to put a chamfer on the Bowden tube. Works fine. But then it occurred to me that i never dared to drill out the connectors, so I still have the small piece of PTFE inside the hotend, which does indeed have a chamfer.

Posted : 28/09/2021 11:17 am
Urshurak776
(@urshurak776)
Eminent Member
No chamfer

No chamfer for me. Straight from extruder right into hotend down to bottom of heatbreak.  Works fine.  

Posted : 01/10/2021 1:07 am
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