Extruder-->Print head PTFE tube couplers replacement
 

Extruder-->Print head PTFE tube couplers replacement  

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eugene.nep
(@eugene-nep)
New Member

Has anyone replaced those weird brass couplers?

I assume I need PC4-M8 size that is nowhere to be found in the US.

The problem that PTFE tube gets pushed out of these couplers for some reason, and olive brass inserts damage PTFE tubing, so not only I have to replace PTFE tube, but I can not reuse same inserts, and sure thing I can not buy replacement fast.

Posted : 23/09/2020 3:57 am
mcjamez
(@mcjamez)
Active Member

There were replacements in my extras bag. I bought more on eBay. https://www.ebay.com/itm/222107931567

Posted : 23/09/2020 4:29 am
eugene.nep
(@eugene-nep)
New Member

@mcjamez

Yes thanks these are exactly what they use. But the problem with whole system is that it does not hold PTFE tube in my case and damages it. I would love to switch to more conventional and widely used couplers such as PC4-M10 fittings, in Prusa's case PC4-M8 ones, that are only available from China.

Posted : 23/09/2020 4:50 am
Karl Herbert
(@karl-herbert)
Famed Member
Posted by: @eugene-nep

Has anyone replaced those weird brass couplers?

I assume I need PC4-M8 size that is nowhere to be found in the US.

The problem that PTFE tube gets pushed out of these couplers for some reason, and olive brass inserts damage PTFE tubing, so not only I have to replace PTFE tube, but I can not reuse same inserts, and sure thing I can not buy replacement fast.

After the PTFE tubes with the original Prusa Mini crimp connections regularly popped out despite a proper tightening torque, I now use PC4-M8 connections. There are probably qualitative manufacturing differences with tolerance deviations in the crimp connections. The same with the PTFE tubes.
In any case, the thing works without any errors so far.
I bought the PC4-M8 here: https://de.aliexpress.com/item/32967678995.html?spm=a2g0s.9042311.0.0.3bfd4c4ddxrDJr

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen....
Posted : 23/09/2020 7:47 am
eugene.nep
(@eugene-nep)
New Member

@karl-herbert

I used PC4-M6 and PC4-M10 or so many different printers and never had any issues w Bowdens.

I wonder why Prusa has chosen to use this weird copper pressure fittings that do not work for quite a few people.

Posted : 23/09/2020 3:29 pm
ignacmc
(@ignacmc)
Active Member

Yes I am about to change to PC4-M8 pass through couplings with the added benefit of allowing to use only one piece of PTFE from extruder to hotend instead of three separate pieces...Can't understand their choice.

Posted : 19/10/2020 3:07 pm
Karl Herbert
(@karl-herbert)
Famed Member

@ignacmc

when using Pc4-M8 you have to make the PTFE tube about 4-5 cm longer. I use this PTFE here:

https://www.captubes.com/ (XS series)

and can really recommend them 👍 

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen....
Posted : 19/10/2020 3:29 pm
ignacmc
(@ignacmc)
Active Member

Yes I suppose you mean that I have to make a bowden tube as long as the sum of the lengths of the three PTFE tubes I intend to replace (43.4 + 275 + 15.1) plus maybe a few millimeters more to account for the part of the brass couplings which separates one PFTE tube from its neighbour. In any case if I make it in only one piece, I think I don't have to be that accurate regarding length...a few mm more or less shouldn't mind 😉

And yes, another advantage of this solution is the ability of using Capricorn XS tube (which is also my favourite). If you intend to use XS with the damned brass olives, you need a suitable drill bit or shaft to avoid restricting filament path while fitting (and crushing) the olives...But XS internal diameter is 1.9 mm not 2, so it is not easy to find something of this size...

Posted : 19/10/2020 4:21 pm
Karl Herbert
(@karl-herbert)
Famed Member

@ignacmc

I designed the PTFE tube to be a bit longer anyway, so that it doesn't bend too much at marginal positions when moving. With the PC4-M8 and the E3D V6 everything works fine so far:

I print 99% ASA and ABS DuraPro and have no problems loading or unloading the filament.

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen....
Posted : 19/10/2020 6:51 pm
crawlerin
(@crawlerin)
Honorable Member

@karl-herbert

I see you have v6 hotend. Was this one of mounts available on Prusaprinters/Thingy or was this your design?

Also, do you have to adjust for Y offset by 3 mm? I found this https://www.prusaprinters.org/cs/prints/40818 to complement with Afterschnitzel's/Tom Wilkie's design.

Posted : 19/10/2020 9:06 pm
ignacmc
(@ignacmc)
Active Member

I am also thinking about using a Mosquito clone in the future...but i don’t like to have to set a Y offset...I suppose there is no other choice.

Posted : 19/10/2020 9:18 pm
Karl Herbert
(@karl-herbert)
Famed Member

@crawlerin

I rebuilt it according to Tom's idea and stabilized it a bit. Due to the construction there is an offset of about 2mm in Y, but this is no problem when printing. It is currently still a prototype. Changes will be implemented in the course of time, as well as a second fan on the front side.

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen....
Posted : 19/10/2020 9:22 pm
Karl Herbert
(@karl-herbert)
Famed Member

Why did I do this? I have a lot of MK3 spare parts and have had good experience with the E3D V6. I didn't want to invest a lot of money and that's why I decided to go for this solution.
Moquito costs about 150 euro or more and if I need higher temperatures I go for the PT100 solution, which works fine with the MK3 up to 400 degrees C. ( printing Carbon PEEK).

At the mini - thermistor table I did not have to change anything, but can certainly be optimized.

(CarbonPEEK - 360degrees nozzle temp., 150degrees bed temp.) - what I will not print on the Mini!

This post was modified 1 week ago by Karl Herbert
Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen....
Posted : 19/10/2020 9:44 pm
Karl Herbert
(@karl-herbert)
Famed Member

@ignacmc

I think that due to the dimensions of the mosquito hotend there should be no offset in Y. I would ask the distributor.

This post was modified 1 week ago by Karl Herbert
Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen....
Posted : 19/10/2020 9:49 pm
ignacmc
(@ignacmc)
Active Member

Posted : 19/10/2020 10:04 pm
ignacmc
(@ignacmc)
Active Member

There is always going to be some y offset

Posted : 19/10/2020 10:05 pm
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