Reprinting a MK2.5S extruder, changing bearings, additional advice please?
 
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Reprinting a MK2.5S extruder, changing bearings, additional advice please?  

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Kenour
(@kenour)
Estimable Member
Reprinting a MK2.5S extruder, changing bearings, additional advice please?

My trusty 2.5S got quite blocked... Also a section of the extruder started to melt slightly, so, thought it was time to reprint the extruder parts. I temporarily printed them in grey after an 'incident' which resulted in the pinda becoming... separate from the rest of the components.

Anyway, it looks like I should replace my PTFE tubing while it's apart, it's definitely seen better days. I also ordered new bearings (the fancy ones) with my MK3S+, so I'll whack them in too while it's in bits.

My question is, as the MK2.5S is essentially a MK3 extruder on a MK2... right? Should I be able to grab the appropriate files from the MK3S+ files and use them instead of the ones in the "Original Prusa i3 MK2.5 MK2.5S upgrade" zip? As they don't seem to have updated this directory with the current MK3S+ components? Or is the MK2.5S not going to receive any more upgrades in line with the MK3S+? I get that I'll have to make a hole for the X end stop, but they should at this point have parallel development right? If I'm going to print components I might as well print the most current yeah? I wouldn't have thought they were different but I noticed that the fs-cover on my new MK3S+ is different from my MK2.5S, and they're both the current parts available for download.

Also, it seems the heatbreak got a slight kink in the 'blob' incident of 2020... It still prints fine (even though it's extruding on a 1-2% angle), has anyone had any success bending one back without any lasting issues? I'm planning on putting an appropriate nut on it, and giving it a little tap to see how I go.

Just wondering if there's any other tweaks/tips/tricks (still keeping it as stock as I can) to improve it's performance. I'm thinking more component upgrades, like for like, rather than whacking a hemera on it or something... which actually doesn't sound like too bad an idea at the moment actually... 🤔

Cheers all! 👍

Posted : 23/01/2021 12:02 pm
Kenour
(@kenour)
Estimable Member
Topic starter answered:
RE: Reprinting a MK2.5S extruder, changing bearings, additional advice please?

I managed to straighten the heatbreak with a nut from an eSun filament spool. Seems like it was almost made for the job. As the thread in the nut SHOULD be perpendicular to the face, I thought I would just tighten it up until it bottomed out against the heatsink, then I have it another quarter turn (thought I might need to defeat that pesky Young's modulus nonsense). Straight as an arrow now, I'll reinstall and let you know if there's any issues in the future 👍 

Posted : 23/01/2021 1:04 pm
Kenour
(@kenour)
Estimable Member
Topic starter answered:
RE: Reprinting a MK2.5S extruder, changing bearings, additional advice please?

Has anyone just printed all the appropriate MK3S+ parts for the MK2.5S? I don't see how this would be an issue, just need the two holes for the micro switch on the X-axis right?

Posted : 29/01/2021 1:37 am
Chicago Keri
(@chicago-keri)
Estimable Member
RE: Reprinting a MK2.5S extruder, changing bearings, additional advice please?

@kenour

 

I hope all is well with your straightened heatbreak.  That particular weakness along with E3D Nozzle Change Dread is why I recently switched to a Mosquito. One-handed cold nozzle swaps are great!

It's probably best to stick with 2.5S parts. When one starts entering unchartered territory you get unexpected complications like maybe the filament sensor not fitting or working, the Pinda being in a different location than the firmware expects,  possibly the X axis microswitch not only having no mounting point but also possibly no corresponding tab on the X carriage to depress the switch or whatever else that caused Prusa to not release a 2.5S version.

Now of course if you wish to work through the conversion process and adapt the MK3S+ parts to our 2.5S printers,  great!  People have already converted the improved MK3S+ fan nozzle to fit our extruders, and it does finally direct the parts cooling air away from the heat block.  A pity for me that it doesn't fit a Mosquito..... yet! 

¡no entiendo Español!
Nein! Nicht Versteh!
Я немного говорю по-русски но не очень хорошо, и...
I'm not very good at English either! Maybe someday I'll find a language I'm good at?

Posted : 07/03/2021 7:49 pm
Chicago Keri
(@chicago-keri)
Estimable Member
RE: Reprinting a MK2.5S extruder, changing bearings, additional advice please?

@kenour

I went and tried it! Well, the MK3S+ R6 extruder, that is. I didn't bother with the new X-axis ends as they don't have the microswitch mount.  The X-axis microswitch bears against the X-axis carriage, not the extruder, and the carriage is apparently  a carryover.

Someone had already adapted the MK3S+ R6 extruder to the Mosquito, so I printed it out to see what the differences are. It doesn't look like any of the differences would change the basic operation, so I went ahead and installed it.

And it fit and works just great on my MK2.5S.   My test 3D Benchy seems better than usual, without the customary very slight "ringing" on the portside aft of the house section. Other than having to redo the first layer height, it seems to be a drop-in replacement for the R4 or R5 extruder and works perfectly well with the previous generation filament sensor.

Probably the standard E3D version of the R6 should replace the R4 or R5 if that's what you're using.

I wonder why the R6 hasn't been released for the MK2S? It seems to work OK.

¡no entiendo Español!
Nein! Nicht Versteh!
Я немного говорю по-русски но не очень хорошо, и...
I'm not very good at English either! Maybe someday I'll find a language I'm good at?

Posted : 11/03/2021 12:32 am
Hiro Protagonist
(@hiro-protagonist)
Active Member
RE: Reprinting a MK2.5S extruder, changing bearings, additional advice please?

Ah, I just made a new post about this!  Great!!  I am going to print the 3S+ parts and try to throw it on using the Dragon I have coming. I'll try to write a post about it so people can look it up later.

Posted : 04/03/2022 5:00 am
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