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Ed
 Ed
(@ed-4)
Eminent Member
MK2s or MK3 at this point?

I made a late preorder for a MK3, which will be my second 3D printer after using a Cetus for about two months.

After reading a lot of forum posts about print quality issues (overextrusion, ringing, stealth-mode-layer-shifting), build quality issues (not enough infill on important printed parts, twisty belts, etc.), and watching Tom's live-stream of every major new feature of the MK3 failing or at least not living up to expectations, I'm considering cancelling my order and getting a MK2s instead.

So, Prusa-forum dwellers, am I being too hasty? Is there any chance that hardware issues might be addressed before mid-February, when my unit is supposed to be shipped?

I'm not afraid of tinkering, but the Cetus has basically printed flawlessly (on rafts, in PLA) since I got it, so I'm now accustomed to a machine that I can happily leave running while I'm at work and have a perfect print (again, on a raft... in PLA) when I get back.

Posted : 26/12/2017 6:57 pm
Dewey79
(@dewey79)
Honorable Member
Re: MK2s or MK3 at this point?

Edward, what people are reporting can be a little unsettling and I'm watching closely in hopes of things getting better also. Other than $150 savings I don't know the differences between the MK2s and the MK3 to give you any advice, but I'll be watching the responses.
My order ships just two weeks before yours so I'm going to check out the differences between models, but more as a curiosity. I'm not ready to jump ship yet. And some people are having good results so is it the holiday rush or expanded personnel we don't know.

There have been people with the MK2 and MK2s that are reporting problems, just not as many. Are these issues cropping up have anything to do with what is happening to the MK3?

Posted : 26/12/2017 7:16 pm
jason.s6
(@jason-s6)
Trusted Member
Re: MK2s or MK3 at this point?

I’m hoping that it could be something in the firmware that is causing print quality issues. I love how quiet it prints and the bed is amazing but at the end of the day you want decent prints. Hopefully these issues will be worked out but until then I’m having to do my prints on the MK2 still. Hopefully now Christmas is over we might hear something

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Posted : 26/12/2017 7:25 pm
kaina.c
(@kaina-c)
Active Member
Re: MK2s or MK3 at this point?

I wouldn't worry about it. I expect most of the issues to be resolved in January and probably more improvements quarterly after that. Some of the complaints are probably build related. If you bought an assembled printer you should have no issues. My kit is printing just fine and will be improved with a few more tweaks. But, that's what 3D printing with a kit is all about. If you want a perfect printer out-of-the-box, you'll need to spend four times as much money. The MK3 is still a great printer out of the box compared to any price points below it, and many above it.

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Posted : 26/12/2017 7:32 pm
JLTX
 JLTX
(@jltx)
Reputable Member
Re: MK2s or MK3 at this point?

I would still get the MK3. Here's why: the hardware/electronics platform it's built on is solid and top notch. Nothing on the MK3 is less capable or lower quality than MK2. All remaining problems I expect to be sorted out in SW, both slicer and firmware. The early users find a lot of the warts that need addressing. Go back in time to the forums when MK2 was first released and the picture was very similar.

And when the MK3S shows up one day, you can upgrade for little $, but MK2.5 will eventually run out of steam for upgrades.

I can't sit through 2.5 hours of live stream. What failures did Thomas run into?

Posted : 26/12/2017 8:29 pm
JLTX
 JLTX
(@jltx)
Reputable Member
Re: MK2s or MK3 at this point?

case in point: new drivers and firmware are out, addressing some of the early issues.

Posted : 26/12/2017 10:00 pm
gorkish
(@gorkish)
Eminent Member
Re: MK2s or MK3 at this point?

I would stick with the MK3. I have one and after working out the minor issues with extrusion it's fine. It can certainly capable of MK2-level quality quieter, at faster speeds, and with more convenience features.

I don't really think it's fair to lay down extreme punishment when convenience features designed for error conditions don't kick in 100% reliably
1) I have never had the print head crash into anything where the print would have been recoverable
2) I have never had the power go out on me while printing.

I have had a layer shift or two and maybe the skip detection would have caught it and recovered the print. Maybe if the power goes out I can recover a print. That's good enough for me.

The removable bed is awesome. Not having to deal with endstops or the mk2 frame assembly was awesome. The 24V heatbed warms up so much faster than my 12v machines. And "normal" mode is incredibly quiet. Those features alone are worth the price.

Einsy not being 32bit was a real bummer and the LCD is still the same old cheap crap. Those are the only two things I would have done different. But they dont' really affect the machine's performance at all.

Posted : 26/12/2017 10:09 pm
edith.f
(@edith-f)
Active Member
Re: MK2s or MK3 at this point?

my mk3 is freaking loud.
i have a prusa i3 from bq, completely modified but still on lm8u bearings but with tmc2100 driver, still on 12 volt and it is silent in comparison to the mk3.

Posted : 26/12/2017 10:23 pm
Ed
 Ed
(@ed-4)
Eminent Member
Topic starter answered:
Re: MK2s or MK3 at this point?


I can't sit through 2.5 hours of live stream. What failures did Thomas run into?

The power panic failed once, then did not retract the print head on a second attempt, leaving a big blob upon recovery. The filament runout sensor worked once, but failed the first time by not triggering until the filament was already too far into the extruder to retract. The shifted-layer detection worked once, but failed when the head was nudged rather than blocked (we can all be forgiven for expecting this feature to work this way, it was demoed at MakerFaire (or another trade show, I don't recall))

Overall, it just seems like Prusa Research's new focus on improving user experience is a little half-baked at the moment. Great ideas, but maybe rushed out the door a bit too soon.

Thanks for the input everyone!

Posted : 26/12/2017 10:51 pm
Ed
 Ed
(@ed-4)
Eminent Member
Topic starter answered:
Re: MK2s or MK3 at this point?

By the way, C.R.T's test stream went some way to make me feel better about the decision to stick with the MK3. Here's hoping Joseph and the research team iron out the kinks by the time I get my unit!

Posted : 27/12/2017 12:52 am
george.b2
(@george-b2)
Estimable Member
Re: MK2s or MK3 at this point?

MK3 all the way!

My MK2s is still great, by the MK3 is sooo much more quiet and sturdy. I too have been a bit frustrated with the early issues, but I am confident they will be worked out. I was having problems getting a good benchy printed with the provided filament. But, I just printed two perfect benchies with Inland (eSun) filament from Micro Center. 3d printing is far from plug and play. More like plug and experiment.

...
Posted : 27/12/2017 12:58 am
luke.m9
(@luke-m9)
Eminent Member
Re: MK2s or MK3 at this point?

My printer will also ship mid February, and I've been quietly debating the same thing as well. From what I understand however, most of the issues are firmware and software related and not actually related to the build of the printer aside from maybe some cooling issues which are usually pretty straight forward to fix even if it means a new a new layer fan. The print quality issues are the thing i'm keeping my eye on the most however. Very concerning.

If the MK3 was kinda different than the 2, I'd have already switched but man, between the removable beds, noise level, aluminum extrusion, 24V components and Einsy board, Bontech gears, and overall just being the start of a new generation I'm extremely hesitant to fall back on a printer that's essentially at the end of its life cycle.

And to be honest, while i've not owned a Prusa before I trust Prusa Research to make things right as quickly as they can. There's not really anything of MK3 caliber in the price range. I've got a heavily modifed Monoprice maker select with about a month of print time on it and I'm ready for a real upgrade, not a sideways slide to another Chinese (bless their hearts) kit printer.

Edits for clarity.

Posted : 27/12/2017 1:48 am
ewout.s
(@ewout-s)
Eminent Member
Re: MK2s or MK3 at this point?

I have contemplated the same thing as this will be my first 3d printer. I strongly prefer to have something that is consistent and doesn't do anything funny so I can reliably learn how to tune these things so the 'random' issues quite scare me.

In the end I decided to stick with my mk3 order and assume everything will be solved eventually as people get to grips with this new manufacturing system. I'm a mechanical engineer by trade and it's not unusual to see issues at the introduction of a new production machine. Still not nice to see people having issues obviously.

My assessment was that the mk3 should be a more consistent platform with its better frame and sensors and was worth it in the end. Why we see people struggling with print quality all of a sudden is beyond me though as I got the impression the mk3 is, conceptually, identical to the mk2. Unfortunately I simply don't have the knowledge or experience to say why, let alone fix it.

So yes, still a bit nervous until I see the word *solved* appearing next to the word 'issue' in more posts but, as mentioned previously, the mk2 is of a previous generation.

Looking forward to receiving my printer next month. In the mean I wish all the earliest of early adopters to build up knowledge and understanding of the mk3 which will help us all to make baby sit up and beg in the longer term.

Posted : 27/12/2017 9:15 pm
ed
 ed
(@ed-3)
Reputable Member
Re: MK2s or MK3 at this point?

I too am a little uneasy right now... I was almost purchased a Makergear M3 ID when they were on sale and am wondering if I made the right choice... I enjoy building things so am kind of looking forward to building my own unit but sure have uncertainty.

Posted : 28/12/2017 12:37 am
JLTX
 JLTX
(@jltx)
Reputable Member
Re: MK2s or MK3 at this point?

Quick review of new awesome sauce on MK3 for you doubters:

1. removable build plate - works great! Better than I expected
2. filament sensor - you'll never go back (fixed in latest firmware): auto load, detect run out or jam
3. bondtech gears - perfect extrusion (haven't test flexible yet but expect great results)
4. temp compensated PINDA - consistent first layers so far across PLA, ABS, PETG
5. New Y axis - simple build and perfect alignment, faster printing
6. Trinamic drivers - crazy quiet and fast
7. Noctua fan - I think it's running

Not yet tested by me:
8. RPM sensing fans - improved reliability
9. power fail detect - good potential, maybe some sw tweaking
10. knock sensing - intermittent success, refine firmware

So you want to cancel your order because maybe 9 and 10 are spotty? The print quality is nearly there, just needs more tuning. Whole new Einsy board with trinamic drivers will take some tuning to perfect.

Posted : 28/12/2017 2:03 am
ed
 ed
(@ed-3)
Reputable Member
Re: MK2s or MK3 at this point?


. ....
So you want to cancel your order because maybe 9 and 10 are spotty? The print quality is nearly there, just needs more tuning. Whole new Einsy board with trinamic drivers will take some tuning to perfect.

Doubt != desire to cancel... Unfortunately, I'm the type of person that questions my actions more than I try to justify them so the doubt will linger until the build is complete.

Posted : 28/12/2017 2:28 am
JoanTabb
(@joantabb)
Moderator
Re: MK2s or MK3 at this point?

I bought the Mk3 and it arrived before Christmas, I wasn't in a good mindset, and did nothing with it...

Since then, I have built it in a leisurely manner,

It was generally easier to assemble than the Mk1 or mk2
and so far it seems to be printing well.

I used the cable tie to set Pinda height, and it seems to be too low, currently my LiveZ is over 1mm... which I don't really like

but it's working, so I am leaving it for the time being.

prints pop off the bed as advertised,

so far I haven't goaded it into power panic or lost step correction, the filament sensor is on, and has not false triggered,

I printed two prusa logo's with the firmware as delivered, the first one seemed to a little bit bonkers just before it finished... but the second one was fine.

then I updated to the latest version, 3.1.1 RC3 b138 and printed another prusa logo and a modified fan shroud, all have come out well.

On the original firmware the printer was quieter on the Z axis. than it is now. this is a minor observation and not entirely surprising since the change log identifies increasing the current to the Z motors.

I have been printing for over an hour at 0.10 layer height, the X, Y and Z are marginally warmer than ambient, the extruder is warmer, but in no way could I call it hot...

the Mk3 printer is definitely quieter than my Mk2
and stringing is much less of an issue than the Mk2 with MMU.

on the first few prints, I would say that there is more dribbling of filament during 9 point levelling than I noticed in the original mk2 before adding the MMU,

I think that my LiveZ is still a touch high, as i mentioned above I was concerned at the amount of live Z correction, so I erred on the safe side. this is not a printer problem, its down to me wanting to go carefully in the beginning...

so all in all I am pleased with my Mk3, so far...

I am using, Chinese filament, and basic Slic3r settings I have lowered the first layer filament temperature to 210c, and the bed to 50c the remaining layers have 205c and 50c respectively. and everything is going well except for two tiny elements which have negligible contact area with the heated bed, which have moved... perhaps I was expecting too much. maybe I should have used a brim, maybe more live Z would have worked, these are all things to tune later... what I am printing is probably a bit ambitious for a first model sliced for an unfamiliar machine. however I am expecting good results... so why do a simple print...

I am definitely not maximising my chances of success, the filament is probably 6months old and has never been kept in a sealed container since the bag was opened...

and yet against all the odds, it's printing well so far...

assuming the print ends well I will pop a picture on here tomorrow.... well later today in reality.

regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK...
Posted : 28/12/2017 3:00 am
ed
 ed
(@ed-3)
Reputable Member
Re: MK2s or MK3 at this point?


.......
and yet against all the odds, it's printing well so far...

assuming the print ends well I will pop a picture on here tomorrow.... well later today in reality.

regards Joan

Thanks Joan... I appreciate you sharing your initial impressions. Now as far as the P.I.N.D.A height, you say you would have set it higher than the thickness of the zip tie? I'm kind of a numbers guy so I struggle with using a zip tie to set height though I realize it's little more than an initial setting.

Posted : 28/12/2017 3:24 am
luke.m9
(@luke-m9)
Eminent Member
Re: MK2s or MK3 at this point?



. ....
So you want to cancel your order because maybe 9 and 10 are spotty? The print quality is nearly there, just needs more tuning. Whole new Einsy board with trinamic drivers will take some tuning to perfect.

Doubt != desire to cancel... Unfortunately, I'm the type of person that questions my actions more than I try to justify them so the doubt will linger until the build is complete.

I'm the exact same way. Of course I want this printer to be amazing, I bought one! I wouldn't have otherwise. It just doesn't help that I'm following the forums where all the people who are having problems come to discuss and so I question it over and over.

Posted : 28/12/2017 3:29 am
JoanTabb
(@joantabb)
Moderator
Re: MK2s or MK3 at this point?

prusa produce thousands of machines per week, and yet we are only seeing a small percentage of that number reporting issues.

I feel the need for a pinda probe ramp spacer so that I can adjust the probe more accurately, probably use 0.2mm steps caused by layer height stratification of the slope... but I expect to need much more pinda height than a cable tie can provide.

Bed calls, hope to play more tomorrow...

will probably use the mk2 to print the ramp, whilst I play more with the Mk3

regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK...
Posted : 28/12/2017 3:37 am
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