A simple solution to bowden hot end popping

[bull 0]

I won't bother burying the lead here, it's all about zip-ties. I've only had my Ultimaker for 3 weeks, but it seems to have solved the only issue I had after my build.

Like others, I have a lot of issues with the horseshoe clip just not putting enough pressure on the clamp. Owen's Hot End mod worked for a while, but I just couldn't keep it tight enough. Part of the problem is that the bowden tube was pretty eaten up from the teeth on the clamp...at one point I even cut a clean edge on the feed side of the tube and flipped it around. This held for around 3 hours of printing before another plug formed, and well, you know the story. At least I can take apart the hot-end like a pro now!

So I've ditched the clip completely, and just cinch a zip-tie around the clamp, really letting those teeth dig in. You'll also notice in the photo that I've added another clamp on the top of the hot-end, which seems to help distribute the pressure put on the tube, both during extrusion and gantry movement.

I can't say it's pretty, but I've gone through nearly 100m of filament since, and can get functional prints (parts, non-visible pieces, etc) running reliably at 150mm/s. My hope is that this cheap and easy fix is of help to someone else out there. If it is, let us know!

[destroyer2012 0]

I too have noticed that the horseshoe clip tends to cause the compression fitting to dig into the bowden tube quite a bit after you first attach the tube, thus making it look like the bowden tube is slipping. Once it's dug in however, it will hold. What I've done is just let the compression fitting dig in and form a plug, then I disassemble the hot end (not removing the bowden tube!), remove the plug that's formed, then tighten the aluminum part so the bowden tube fits well into the peek insulator again. All this without removing the bowden tube, and the result is reliable printing. Of course in order for this to work you need to make sure you have the bowden tube stick out quite a bit from the bottom of the print head, so you have room to adjust the PEEK insulator up once the compression fitting starts digging in.

I think the problem people are seeing is because they expect the compression fitting to hold the bowden tube without digging in, and once they see that the bowden tube is moving they assume it has failed, take it apart and cut a bit off the end of the tube, thus restarting the cycle.

[flyguy 0]

This is great !

I lost those blue clips and was going to ask for somebody to send me a drawing so I could mill them out. but I love this idea way better !!!

Thank you !

Brian

[dscheyh 0]

Thank you very much for this simple solution.

I had lost the blue horseshoe clip. In lieu of the horse shoe clip I used also a zip-tie with 3mm height. By tightening with a clamp, it fit perfectly under the white fitting.

[bull 0]

Great to hear it worked out for you too! I've printed another ~100m of filament since my first post and it's still holding strong! Have even found some decent retraction settings for my build and it's been a huge improvement in print quality (or at least less cleanup...)