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Titan
(@titan-2)
Estimable Member
MK3S... Was it worth the upgrade from MK3?

I recently upgraded my Mk3 to the MK3S, primarily because Prusa Research promised the more direct feed path would improve flexible prints - something I wanted to do more of.  The upgrade went a-ok but my experience with the ‘improved’ machine hasn’t been so good.

I loved my MK3 and looked after it well.  It was just fantastic and only ever provided 2 or 3 really minor issues (blocked nozzle etc.) over a year of fairly frequent use.  Due to the quality extruder it was also super simple to keep clean as I had it in an enclosure, used rigid ink’s floss at each filament change and generally gave it a once over every few days.  The whole product was fantastic.

The MK3S extruder by contrast has provided me no end of issues.  I’ve only had it running in its new guise for 3 or so weeks but it’s already clogged 10’s of times, once so badly I had to remove the hot end to get to the PTFE tube.  It just doesn’t seem to print as well as the MK3 using pretty much any filament.  PLA is less user friendly (though still easy) and PTEG is noticeably more difficult to dial in correctly.  TPU (flex) is a nightmare.  And from searching the web it seems I’m not the only one experiencing these issues.

The bondtcch gears seem too grippy even with the door screw unwound to its loosest setting.  The new gear setup creates more dust than the MK3 that increases the chance and frequency of PTFE tube blockages, and the position of the teflon/PTFE tube beneath the gears helps the filament path a little but obviously doesn’t cure the issue of filament backlog, which is now so much worse and   Also the overall extruder design seems to be less forgiving than the MK3 version as the fans need more careful consideration to successfully finish prints.

And if I’m being really picky (and these issues are clearly minor compared to the print issues) the nozzle is slightly harder to get to to clean mid print (I have used long necked tweezers to clean 3D printer nozzles for years and these don’t reach the MK3S nozzle so easily when it’s close to the bed), and the extruder gear door screw is harder to get to with an extended Allen key (or precision driver with Allen bit installed) compared to the MK3 version.

I am disappointed having spent good money and a weekend upgrading and dialling in the MK3S upgrade that is proving worse than the standard MK3.  I’m going to stick with it for now and really hope to find a reason that proves the whole process was worth while.  Otherwise I’m sadly seriously thinking of returning it to a MK3.

Publié : 04/03/2020 1:19 pm
bobstro
(@bobstro)
Illustrious Member
RE: MK3S... Was it worth the upgrade from MK3?

I've stayed with my original Mk3 configuration using the R2 parts and have not regretted the decision. I opted not to install the MMU2, so am only using single filament printing. After spending some time on settings last week, I'm able to print Inland TPE with a shore hardness of 85A without feed problems. The stuff strings, but that's the nature of flexibles. No feed jams at all over many hours of printing.

Sorry you're encountering problems. You've confirmed what has kept me from updating so far!

My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Publié : 04/03/2020 4:02 pm
Nikolai
(@nikolai)
Noble Member
RE: MK3S... Was it worth the upgrade from MK3?

I left my MK2.5 without upgrade to MK2.5s. My MK3 was upgraded to MK3s because of the MMU2s. Both are working fine.

As usual rule of thumb: If it's not broken, don't fix it. I'm also trying to stay on older firmware versions and upgrade only if the new feature/bug fix is really required. For example the last MMU2 upgrade was really a step forward.

Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram

Publié : 04/03/2020 10:39 pm
Titan
(@titan-2)
Estimable Member
Topic starter answered:
RE: MK3S... Was it worth the upgrade from MK3?

@bobstro

Cheers Bob. I think you made a wise call. I don’t believe the r3 or mk3s upgrades are bad or even detrimental to print quality necessarily, but I’m not sure how much better they are at providing genuinely better quality prints, and they certainly don’t make printing well any easier. I feel a bit cheated right now. The r3 print fan placement should theoretically be better, but I’m yet to really notice any improvement.

Maybe it’ll take a while to learn all the best new print settings (Temps, speeds, cooling, retraction etc.) of the mk3s for all types of filament (which is frustrating as I knew the mk3 settings really well). Time will tell I guess.

Publié : 05/03/2020 1:47 am
Titan
(@titan-2)
Estimable Member
Topic starter answered:
RE: MK3S... Was it worth the upgrade from MK3?

@nikolai-r

The mk3 certainly wasn't broken, but Prusa promised significant improvements in flexible filament usage with the mk3s upgrade (which was attractive to me), not to mention overall improved extruder design which would allow for easier use. At this stage I'm not convinced either promise was true. Time will tell if it proves to be better than it seems so far and offer advantages I've not yet discovered.

Publié : 05/03/2020 1:52 am
Titan
(@titan-2)
Estimable Member
Topic starter answered:
RE: MK3S... Was it worth the upgrade from MK3?

I'm experiencing many issues printing TPU (that printed a-ok on the MK3) so to cheer myself up 😝and restore some faith in the printer I decided to print a very simple PLA file that I printed perfectly on the MK3 a number of times and... that's failed too.  Warping and over extrusion.  So it looks like the newer cooling fan design is overly efficient when using the Prusa print settings and - well, I haven't figured out what's causing the over extrusion yet.

I'm so disappointed in what Prusa appear to have replaced the MK3 extruder with.  Apart from the new filament sensor (which I also never experienced an issue with when using the MK3 version) I'm not convinced any single part of the 'upgrade' is an improvement.

Publié : 05/03/2020 2:59 pm
ArmedLeftist
(@armedleftist)
Eminent Member
RE: MK3S... Was it worth the upgrade from MK3?
Posted by: @nathan-b20

I recently upgraded my Mk3 to the MK3S, primarily because Prusa Research promised the more direct feed path would improve flexible prints - something I wanted to do more of.  The upgrade went a-ok but my experience with the ‘improved’ machine hasn’t been so good.

I loved my MK3 and looked after it well.  It was just fantastic and only ever provided 2 or 3 really minor issues (blocked nozzle etc.) over a year of fairly frequent use.  Due to the quality extruder it was also super simple to keep clean as I had it in an enclosure, used rigid ink’s floss at each filament change and generally gave it a once over every few days.  The whole product was fantastic.

The MK3S extruder by contrast has provided me no end of issues.  I’ve only had it running in its new guise for 3 or so weeks but it’s already clogged 10’s of times, once so badly I had to remove the hot end to get to the PTFE tube.  It just doesn’t seem to print as well as the MK3 using pretty much any filament.  PLA is less user friendly (though still easy) and PTEG is noticeably more difficult to dial in correctly.  TPU (flex) is a nightmare.  And from searching the web it seems I’m not the only one experiencing these issues.

The bondtcch gears seem too grippy even with the door screw unwound to its loosest setting.  The new gear setup creates more dust than the MK3 that increases the chance and frequency of PTFE tube blockages, and the position of the teflon/PTFE tube beneath the gears helps the filament path a little but obviously doesn’t cure the issue of filament backlog, which is now so much worse and   Also the overall extruder design seems to be less forgiving than the MK3 version as the fans need more careful consideration to successfully finish prints.

And if I’m being really picky (and these issues are clearly minor compared to the print issues) the nozzle is slightly harder to get to to clean mid print (I have used long necked tweezers to clean 3D printer nozzles for years and these don’t reach the MK3S nozzle so easily when it’s close to the bed), and the extruder gear door screw is harder to get to with an extended Allen key (or precision driver with Allen bit installed) compared to the MK3 version.

I am disappointed having spent good money and a weekend upgrading and dialling in the MK3S upgrade that is proving worse than the standard MK3.  I’m going to stick with it for now and really hope to find a reason that proves the whole process was worth while.  Otherwise I’m sadly seriously thinking of returning it to a MK3.

I’m puzzled. How can extruded gears be “too grippy”? What are the symptoms of that? Seems counter-intuitive to me.

Every man I meet is in some way my superior. --Ralph Waldo Emerson

Publié : 05/03/2020 5:08 pm
ArmedLeftist
(@armedleftist)
Eminent Member
RE: MK3S... Was it worth the upgrade from MK3?
Posted by: @nathan-b20

@nikolai-r

The mk3 certainly wasn't broken, but Prusa promised significant improvements in flexible filament usage with the mk3s upgrade (which was attractive to me), not to mention overall improved extruder design which would allow for easier use. At this stage I'm not convinced either promise was true. Time will tell if it proves to be better than it seems so far and offer advantages I've not yet discovered.

I ordered a MK3s a couple of weeks ago. Has not yet arrived. Given the comments this thread, I wonder if it is possible to downgrade if warranted?

Every man I meet is in some way my superior. --Ralph Waldo Emerson

Publié : 05/03/2020 5:12 pm
Nikolai
(@nikolai)
Noble Member
RE: MK3S... Was it worth the upgrade from MK3?

@armedleftist

You would need to buy additional parts (like the old sensor). You would also loose the warranty. But I wouldn't recommend you to downgrade anything. If you really want to modify your printer, there are tons of other options. It highly depends on your requirements.

For all new users I always recommend: get your printer to know first. Whatever upgrades/modifications are discussed in FB groups and forums are usually highly user specific. Use your printer for the reason you got it in the first place. Print with it!

Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram

Publié : 05/03/2020 5:51 pm
Titan
(@titan-2)
Estimable Member
Topic starter answered:
RE: MK3S... Was it worth the upgrade from MK3?

@armedleftist

In some circumstances filament can sometimes benefit from being able to slip against the driving gear. This theoretically comes at a cost to the quality of the finished print, but many would argue it's an acceptable trade off compared to the alternative - a clogged feeding mechanism and a failed print.

The procedure is commonly associated with flexible filaments (TPE's like TPU and TPC, flexible nylons etc.) but an overly tightened or generally-acceptably-tightened drive mechanism can affect less flexible filaments too if the print temperature settings are incorrect (usually too low, although heat creep from excessive heat can also cause the phenomenon) and if the extruder design allows for 'excess filament' (filament fed through the drive gear but not able to be pushed down into the teflon throat tube).

If the drive gear is set very tight the teeth can gnaw into the filament creating dust and debris (less of an issue with flex filaments) that dirties the extruder mechanism whilst simultaneously forcing the filament out of the side of the extruder or, worse, around the feed gears.  If the drive gear is loosened off before the print it can aid printing by allowing the filament to slip slightly against the teeth, providing the hot end enough time to melt and dispose of stored filament making space for new filament to be fed into the teflon throat tube.  As mentioned, this is most commonly associated with flexible filaments.

The MK3S extruder was designed with a more direct feed path compared to the MK3 so it was suggested that flexible filaments would be handled better.  But in my experience whilst the filament is not coming out the side of the MK3S extruder like it did on the MK3, the bond tech gears are cutting into the TPU and something so far unknown is stopping the filament from successfully exciting the nozzle intermittently during prints.

Publié : 05/03/2020 5:53 pm
ArmedLeftist
(@armedleftist)
Eminent Member
RE: MK3S... Was it worth the upgrade from MK3?
Posted by: @armedleftist
Posted by: @nathan-b20

I recently upgraded my Mk3 to the MK3S, primarily because Prusa Research promised the more direct feed path would improve flexible prints - something I wanted to do more of.  The upgrade went a-ok but my experience with the ‘improved’ machine hasn’t been so good.

I loved my MK3 and looked after it well.  It was just fantastic and only ever provided 2 or 3 really minor issues (blocked nozzle etc.) over a year of fairly frequent use.  Due to the quality extruder it was also super simple to keep clean as I had it in an enclosure, used rigid ink’s floss at each filament change and generally gave it a once over every few days.  The whole product was fantastic.

The MK3S extruder by contrast has provided me no end of issues.  I’ve only had it running in its new guise for 3 or so weeks but it’s already clogged 10’s of times, once so badly I had to remove the hot end to get to the PTFE tube.  It just doesn’t seem to print as well as the MK3 using pretty much any filament.  PLA is less user friendly (though still easy) and PTEG is noticeably more difficult to dial in correctly.  TPU (flex) is a nightmare.  And from searching the web it seems I’m not the only one experiencing these issues.

The bondtcch gears seem too grippy even with the door screw unwound to its loosest setting.  The new gear setup creates more dust than the MK3 that increases the chance and frequency of PTFE tube blockages, and the position of the teflon/PTFE tube beneath the gears helps the filament path a little but obviously doesn’t cure the issue of filament backlog, which is now so much worse and   Also the overall extruder design seems to be less forgiving than the MK3 version as the fans need more careful consideration to successfully finish prints.

And if I’m being really picky (and these issues are clearly minor compared to the print issues) the nozzle is slightly harder to get to to clean mid print (I have used long necked tweezers to clean 3D printer nozzles for years and these don’t reach the MK3S nozzle so easily when it’s close to the bed), and the extruder gear door screw is harder to get to with an extended Allen key (or precision driver with Allen bit installed) compared to the MK3 version.

I am disappointed having spent good money and a weekend upgrading and dialling in the MK3S upgrade that is proving worse than the standard MK3.  I’m going to stick with it for now and really hope to find a reason that proves the whole process was worth while.  Otherwise I’m sadly seriously thinking of returning it to a MK3.

I’m puzzled. How can extruded gears be “too grippy”? What are the symptoms of that? Seems counter-intuitive to me.

“Extruder gears”

Every man I meet is in some way my superior. --Ralph Waldo Emerson

Publié : 05/03/2020 5:54 pm
Titan
(@titan-2)
Estimable Member
Topic starter answered:
RE: MK3S... Was it worth the upgrade from MK3?
Posted by: @armedleftist
Posted by: @nathan-b20

@nikolai-r

The mk3 certainly wasn't broken, but Prusa promised significant improvements in flexible filament usage with the mk3s upgrade (which was attractive to me), not to mention overall improved extruder design which would allow for easier use. At this stage I'm not convinced either promise was true. Time will tell if it proves to be better than it seems so far and offer advantages I've not yet discovered.

I ordered a MK3s a couple of weeks ago. Has not yet arrived. Given the comments this thread, I wonder if it is possible to downgrade if warranted?

I couldn't recommend that as my experience may be something specific to my printer.  Your MK3S (and other people's) may be absolutely fine.  Hopefully with some further testing and help I'll get to the bottom of this and the MK3S will begin to impress.  I'm ever hopeful.  🙂 

Publié : 05/03/2020 5:56 pm
ArmedLeftist
(@armedleftist)
Eminent Member
RE: MK3S... Was it worth the upgrade from MK3?
Posted by: @nikolai-r

@armedleftist

You would need to buy additional parts (like the old sensor). You would also loose the warranty. But I wouldn't recommend you to downgrade anything. If you really want to modify your printer, there are tons of other options. It highly depends on your requirements.

For all new users I always recommend: get your printer to know first. Whatever upgrades/modifications are discussed in FB groups and forums are usually highly user specific. Use your printer for the reason you got it in the first place. Print with it!

 That makes sense. I am adding this printer to the Skuderia but I know what you mean about “getting used to it”. Just thinking ahead. Thanks.

Every man I meet is in some way my superior. --Ralph Waldo Emerson

Publié : 05/03/2020 5:58 pm
Nikolai a aimé
ArmedLeftist
(@armedleftist)
Eminent Member
RE: MK3S... Was it worth the upgrade from MK3?
@nathan-b20
 
“something so far unknown is stopping the filament from successfully exciting the nozzle intermittently during prints.”
 
that’s a bummer! Yes, I was definitely thinking that the “out” (at the nozzle), could not keep up with the “in”.
 
It seems to me that actually making the conscious decision to “grind” the filament (albeit less with flexible filaments as you point out), to fix a problem would be very likely eventually cause problems along the lines of what you describe. For example, if you forgot to re-tighten all and then switched to a non-flexible filament. I could be missing something though.

 

Ce message a été modifié il y a 5 years par ArmedLeftist

Every man I meet is in some way my superior. --Ralph Waldo Emerson

Publié : 05/03/2020 6:06 pm
Titan
(@titan-2)
Estimable Member
Topic starter answered:
RE: MK3S... Was it worth the upgrade from MK3?
Posted by: @armedleftist
@nathan-b20
 
“something so far unknown is stopping the filament from successfully exciting the nozzle intermittently during prints.”
 
that’s a bummer! Yes, I was definitely thinking that the “out” (at the nozzle), could not keep up with the “in”.
 
It seems to me that actually making the conscious decision to “grind” the filament (albeit less with flexible filaments as you point out), to fix a problem would be very likely eventually cause problems along the lines of what you describe. For example, if you forgot to re-tighten all and then switched to a non-flexible filament. I could be missing something though.

 

The technique is not to purposefully grind the filament, the conscious decision to loosen the adjustable screw is to allow filament to be placed under reduced tension with the intention of allowing it to partially 'slide' past the drive gear which avoids grinding the filament if too much pressure is exerted by the hot end.  Getting the tension of the adjustable screw correct is the art form.  As long as the screw is tensioned correctly the flex filament won't create much of any dust or debris (this is more the case when harder filaments get chewed up between highly tensioned drive gears).  Dirt and debris isn't what's causing the issues I'm experiencing.

FYI. Adjusting the bond tech tensioning screw is something that should be done as often as necessary when changing filament types, just like changing the live Z value when swapping out filaments, or setting new bed level heights for every steel textured or smooth print sheet.  It's all part of the fun! 😎 

Ce message a été modifié il y a 5 years 3 fois par Titan
Publié : 06/03/2020 12:50 am
ArmedLeftist
(@armedleftist)
Eminent Member
RE: MK3S... Was it worth the upgrade from MK3?
Posted by: @nathan-b20
Posted by: @armedleftist
@nathan-b20
 
“something so far unknown is stopping the filament from successfully exciting the nozzle intermittently during prints.”
 
that’s a bummer! Yes, I was definitely thinking that the “out” (at the nozzle), could not keep up with the “in”.
 
It seems to me that actually making the conscious decision to “grind” the filament (albeit less with flexible filaments as you point out), to fix a problem would be very likely eventually cause problems along the lines of what you describe. For example, if you forgot to re-tighten all and then switched to a non-flexible filament. I could be missing something though.

 

The technique is not to purposefully grind the filament....

Of course not, that would be silly. 

FYI. Adjusting the bond tech tensioning screw is something that should be done....

I suspect that is likely simply a matter of uncritical cultural habit. A simple evaluation of the various forces at play reveals that to overly-complicate the process.

Again, reducing variables in any endeavor is always the smart/efficient move, hopefully bypassing the frustration that is inherent in managing more “moving parts” than is actually necessary.

 

Every man I meet is in some way my superior. --Ralph Waldo Emerson

Publié : 06/03/2020 2:39 am
Titan
(@titan-2)
Estimable Member
Topic starter answered:
RE: MK3S... Was it worth the upgrade from MK3?
Posted by: @armedleftist

I suspect that is likely simply a matter of uncritical cultural habit. A simple evaluation of the various forces at play reveals that to overly-complicate the process.

Sure. 🙂 

Publié : 06/03/2020 8:48 am
Texy
 Texy
(@texy)
Reputable Member
RE: MK3S... Was it worth the upgrade from MK3?

Two of the main positives pushed by Prusa for upgrading were the improved filament sensor and extruder design.

Well I never had a problem with any filament with the mk3 sensor, and I read that the new extruder brought its own issues.

So I never bothered with upgrading it.

Texy

Publié : 06/03/2020 10:18 am
Titan
(@titan-2)
Estimable Member
Topic starter answered:
RE: MK3S... Was it worth the upgrade from MK3?
Posted by: @texy

Well I never had a problem with any filament with the mk3 sensor, and I read that the new extruder brought its own issues.

So I never bothered with upgrading it.

Texy

Sounds like you're happy with your choice, which is great.  👍 Perhaps I should have stuck with the same train of thought except, as I mentioned, the MK3 was not good at printing flexible filament and that was the primary reason I took the plunge.  Still, I may still crack it yet and if not I can always return it to MK3 guise.

Publié : 06/03/2020 10:27 am
Texy
 Texy
(@texy)
Reputable Member
RE: MK3S... Was it worth the upgrade from MK3?

I should also add that I only print in PLA, so nothing exotic. However I have a plan to try TPU or another flexible, for a project idea one day.

Would you argue that for you, mk3 is better at handling flexi, or mk3s ?

Texy

Publié : 06/03/2020 10:59 am
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