Mini+ Hotend PTFE tube still an issue?
Was looking at taking the plunge with a mini+, but have been reading about the clogging issues due to the tube. They all seemed to be from a while back so was wondering if Prusa has implemented a fix on later + models?
Thanks,
Gary
RE: Mini+ Hotend PTFE tube still an issue?
That’s kind of what I was thinking, but thought I’d put the question out there.
RE: Mini+ Hotend PTFE tube still an issue?
Prusa have made many thousand Minis, a few dozen users have come here with PTFE tube issues.
That was my same view. And if it does become an issue, the Bondtech extruder is certainly an option.
RE: Mini+ Hotend PTFE tube still an issue?
The issue that was originally reported was that the MINI came with a too-short PTFE tube. I believe this is now fixed.
However, while I love my MINI+, AFAIK the fact that the hotend is PTFE-lined inevitably means that the PTFE tube will eventually shrink and potentially cause a partial (or if you're unlucky, full) clog. It takes a while to become an issue (if ever), though, at PLA printing temps. If you regularly print higher-temp materials, this could become more of a nuisance.
In the end, the fix is easy: if the tube is only slightly shrunk, recompress the tube using steps 10 and up from this procedure, else replace it with a new one. I now view the hotend PTFE tube as an expendable item (as someone else on this forum previously said) which is why I keep a few in stock for occasional replacement. Someone please correct me if I'm wrong, but as far as I know this is just the way it is and nothing more can be done to avoid this.
Other than that the MINI+ has truly been a joy to use and prints great.
RE: Mini+ Hotend PTFE tube still an issue?
I've bought the Bondtech heat breaks for my Minis but they are still sitting unused in a drawer. I haven't had any issues, and my two Minis have many months of print time on them. I do have the Trianglelabs clone of the Bondtech extruder installed though, which I think is a huge improvement over the stock extruder
RE: Mini+ Hotend PTFE tube still an issue?
I've bought the Bondtech heat breaks for my Minis but they are still sitting unused in a drawer. I haven't had any issues, and my two Minis have many months of print time on them...
I'm curious... do you mix filament types on those two printers, or you use PLA mostly?
I ask, because it's the fact, that PTFE tube shrinks at higher temperatures inside stock heatbreak. In your post however, it sounds like you never had the need to disassemble hotend.
[Mini+] [MK3S+BEAR]
RE: Mini+ Hotend PTFE tube still an issue?
Wild guess: 60% PETG 30% PLA 10% others (ABS, wood etc). TPU and PC I use the Mk3S for.
i should also say that I replaced the good old Bowden tube with one that has PC4 adaptors. But they're not the push through type so there's still a small piece of PTFE tubing in the extruder. Don't see why that would make a difference but as I said I never had any issues.
RE: Mini+ Hotend PTFE tube still an issue?
Thank you all for the information. I'm new to the 3D printing world.
I did place an order for the Mini+ so I'm sure I'll be back on here many more times.
RE: Mini+ Hotend PTFE tube still an issue?
Your question has reminded me that I once replaced my Bowden tube after a jam. I bought many new tubes as it gave best economy for postage charges. I fitted a single new tube so long ago that I can’t remember when that was. While the design of the Mini has not changed, the shrinking Bowden tube is for me a non-issue. You don’t need to worry about it.
Meanwhile, my Mini (now a Mini +) was dormant all summer and has now come out of hibernation as I switch to winter indoor life. It’s making print after print after print without tuning and with ‘start and forget’ reliability.
RE: Mini+ Hotend PTFE tube still an issue?
I still have the original PTFE tube delivered with the Mini printer I received in December 2019. I have a spare, but see no reason to change yet.
The Mini mostly prints in PETG (95%) a couple of times each week, more exotic materials are done on my MK3s.
Have a look at my models on Printables.com 😉
RE: Mini+ Hotend PTFE tube still an issue?
I think the higher temperature ASA is what wore it out. I printed many rolls of PETG with no problems. It went from printing perfectly to clogging all the time in a few hours, after a couple rolls of ASA.
Regards,
Mark
RE: Mini+ Hotend PTFE tube still an issue?
hi gary,
i have read many post about this PTFE issue, and i think the problem is not the design of the mini/mini+, but the thermal paste on the heatbreak. people who received the mini with a good amount of thermal paste on the heatbreak, mostly not going to have the PTFE tube shrinking problem. but some people who are not lucky (like me) in the first two month of printing, my mini+ start to clogged and i change the PTFE tube a few times, even with capricorn tube, but my PTFE still shrinking and start to clog. but after re apply the thermal paste, my mini never clogged anymore after 7 months of printing PLA / PETG / (some Nylon) with original stock mini+
many review says after changing the bondtech heatbreak the print results back to normal, because maybe when they change the heatbreak to bondtech, they are applying a good amount of thermal paste on it, after that the issue is gone.
ps : now i'm waiting fo next black friday and buy another mini+ because i love this machine so much 🙂
RE: Mini+ Hotend PTFE tube still an issue?
.. i think the problem is not the design of the mini/mini+, but the thermal paste on the heatbreak.
Yes, that crossed my mind too!
Some have PTFE tube problem all the time, while other say no problem at all (or very rare). There are quite some factors that influence hotend endurance: bad chamfer on PTFE tube, heatbreak not tightened enough,.. and finally, not properly assembled hotend.
And then, some have their own theories about how much thermal paste should be applied. For example, for CPU cooler, very thin layer should be applied (there's a reason for that), and so they assume the same is true for heatbreak -which is wrong, of course.
many review says after changing the bondtech heatbreak the print results back to normal, because maybe when they change the heatbreak to bondtech, they are applying a good amount of thermal paste on it, after that the issue is gone.
-yes. And opposite: some were disappointed by Bondtech, went back to stock heatbreak and problems are gone (at least for a while). However, in majority of cases, it turns out, heatbreak wasn't assembled properly.
[Mini+] [MK3S+BEAR]
RE: Mini+ Hotend PTFE tube still an issue?
No reason to buy the precut and pay for international shipping on them. You can go on amazon and buy PTFE tube in lengths of many feet for a few $. Prusa has the exact measurements the tubes need to be cut to in their knowledge base and you can print a jig for cutting the tube square with a razor blade. This is what I do. I also replaced my crush "olive" fittings with pneumatic fittings because they kept failing over time and the tube popping out mid print. The pneumatic fittings have a side effect of the teeth that grip the tube slowly chew into the tube, so I just replace the tube between the extruder and hot end every couple months before it chews too deep into the tube and it either fails or you just can't get it out of the fitting. I consider all of the PTFE tubing to just be wear items that need to be changed periodically. The end of the tube where the filament enters needs to have a taper cut into it so the filament doesn't catch on it during loading. This can simply be done by twisting the tube on the corner of a razor blade a few times. Then use a can of compressed air to blow out the shavings from inside the tube. You don't want those getting down into the nozzle, it can't melt the PTFE and will likely just plug your nozzle.
RE: Mini+ Hotend PTFE tube still an issue?
Here is the link to the PTFE Tube Chamfer and Cut Jig I made some years ago to make and chamfer PTFE tubes to the right length.
Have a look at my models on Printables.com 😉