Bowden tube fittings  

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JASII
(@jasii)
Estimable Member

Has anyone received a Mini with Festo fittings instead of the brass compression fittings? The reason for asking is that I am designing adapters to use other hotends on the Mini using the existing Bowden configuration.

Mine is brass compression but the pictures on the product page and blog show chrome Festo while the parts page shows compression. This was brought to my attention by a thread in Reddit.

My compression fittings:

Below image from product page showing Festo:

Reddit thread has some suggesting Festo was prototype and early models with compression being the final production. Others are saying that is reversed with Festo to come 🙂 Thank you for your time. Jerry.

05/2017 - MK2s - 09/2017 +MMUv1
12/2017 - MK3 - 07/2018 + Mosquito hotend
12/2018 - ↑MK3s w/MMU2s
01/2019 - ↑MK2.5s w/MMU2s
03/2020 - Mini
06/2020 - MK2/3/MINI + Copperhead Hotend
Win 10 64bit - AD Inventor -…...
Posted : 04/04/2020 10:24 pm
Matteo Cristini
(@matteo-cristini)
Reputable Member

My mini came with the brass fittings. I think every mini has them, not sure why there's the festo ones in the picture in the eshop

Posted : 04/04/2020 10:33 pm
JASII
(@jasii)
Estimable Member

Thanks. As I see the Festo fittings in the Prusa videos and photos, dating from October-December 2019, I will assume that they were just for prototyping and will design my adapters for the compression fitting.

This post was modified 2 months ago by JASII
05/2017 - MK2s - 09/2017 +MMUv1
12/2017 - MK3 - 07/2018 + Mosquito hotend
12/2018 - ↑MK3s w/MMU2s
01/2019 - ↑MK2.5s w/MMU2s
03/2020 - Mini
06/2020 - MK2/3/MINI + Copperhead Hotend
Win 10 64bit - AD Inventor -…...
Posted : 05/04/2020 10:36 pm
jens-1
(@jens-1)
New Member

Does anyone know if you can buy those brass compression fittings somewhere? They are not in the Prusa spare parts shop (unless you buy a while heat sink). And I'm so terribly sick of those shitty "Festo" fittings that really is a single direction fitting that destroys the PTFE tube on use.

Posted : 12/04/2020 8:35 pm
Ddx30 liked
JASII
(@jasii)
Estimable Member

Depends on location. Here in the US, just Google, "M8 brass compression fittings", and you will find multiple sources. The thread into the heat sink on my unit is M8x1 with the tube OD of 4mm.

Note that the sleeve that slides onto the PTFE tubing gets compressed 'onto/into' the tube when you first tighten it (it comes compressed from Prusa). I know this also from working with the same set-up on robotic pneumatics. This essentially means it is non-removable. I do agree that with these fittings, and our low preassure use, you can remove/insert the tube multiple times to clear clogs or whatever, and the tube is only 'squeezed' once vs. each time if you reinsert into a Festo. But if you want to change or replace the tube in an existing compression fitting then you will need to get extra compression sleeves.

05/2017 - MK2s - 09/2017 +MMUv1
12/2017 - MK3 - 07/2018 + Mosquito hotend
12/2018 - ↑MK3s w/MMU2s
01/2019 - ↑MK2.5s w/MMU2s
03/2020 - Mini
06/2020 - MK2/3/MINI + Copperhead Hotend
Win 10 64bit - AD Inventor -…...
Posted : 12/04/2020 9:38 pm
j-martin
(@j-martin)
Active Member

I’m going to try going the other way. 

My compression ring on the extruded end is over crimped and it has narrowed the diameter of the bowden tube. 

If The print finishes and I don’t unload/retract it immediately it’s pretty much stuck there until I disconnect the brass connector and  cut  off the distorted tip of filament clean so it can retract back. 

The  workaround is to go through the heat up cycle then purge and then it will retract but it all adds time. 

I’ve seen a file somewhere that someone drew up a set of adapters to allow Festos to screw into the existing threaded holes on the mini. Can’t find the article or files though. 

If anyone has the link let me know please. 

This post was modified 2 weeks ago by j-martin
Posted : 23/05/2020 12:33 am
JASII
(@jasii)
Estimable Member

@j-martin

I think this is what you may have seen.

https://www.prusaprinters.org/prints/30001-prusa-mini-pc4-m6-bowden-fitting-adapter

05/2017 - MK2s - 09/2017 +MMUv1
12/2017 - MK3 - 07/2018 + Mosquito hotend
12/2018 - ↑MK3s w/MMU2s
01/2019 - ↑MK2.5s w/MMU2s
03/2020 - Mini
06/2020 - MK2/3/MINI + Copperhead Hotend
Win 10 64bit - AD Inventor -…...
Posted : 23/05/2020 3:23 am
Ddx30
(@ddx30)
New Member

does anyone know how to fix the brass compression fittings to the PTFE? my mini came (yesterday) with one of the fittings loose, so did not make much of printing unfortunately after the 5 months wait... I can use pliers but they will not look pretty... and the initial try to fit the one that was loose with it was not very successful. I would like to fit one of the new ones that come in te spares bag, but would like to know if anyone knows teh appropriate way to do so....

thx a bunch

Posted : 04/06/2020 5:36 pm
JASII
(@jasii)
Estimable Member

@trevino-david

Compression rings compress (tighten) when you screw down the nut onto the seat.

  1. Place the compression nut on the PTFE tube
  2. Then place the compression ring on the tube
  3. Insert the end of the tube into the threaded seat
  4. Slide the nut down (which will also slide the ring)
  5. Tighten the nut while keeping the tube pressed into the seat

The tube should now be 'locked' in place. If you unscrew the nut you will find the compression sleeve is now pressed into the tube slightly and will not move.

 

This post was modified 15 hours ago by JASII
05/2017 - MK2s - 09/2017 +MMUv1
12/2017 - MK3 - 07/2018 + Mosquito hotend
12/2018 - ↑MK3s w/MMU2s
01/2019 - ↑MK2.5s w/MMU2s
03/2020 - Mini
06/2020 - MK2/3/MINI + Copperhead Hotend
Win 10 64bit - AD Inventor -…...
Posted : 04/06/2020 5:47 pm
Ddx30 liked
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