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Love at First Print  

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iamloremipsum
(@iamloremipsum)
Eminent Member
Love at First Print

Just received my assembled mk3 on Friday night. I purposefully wanted to see how well the printer worked without making any adjustments whatsoever. I loaded the Prusa Filament, pulled up a model of mine and pressed go. I am floored at the results. (Images should be attatched)

Printed with “optimal settings” (.15 mm)
Print times 24hrs (Print estimate was off by 10hrs!)

Opublikowany : 09/09/2018 11:56 pm
thrawn86
(@thrawn86)
Honorable Member
Re: Love at First Print

thats a heck of a first print.

.15 is technically not ideal on the mk3 due to the resolution of the z axis (use .16 or .12 instead) but not a huge deal.

Opublikowany : 10/09/2018 5:28 am
bobstro
(@bobstro)
Illustrious Member
Re: Love at First Print


thats a heck of a first print.

.15 is technically not ideal on the mk3 due to the resolution of the z axis (use .16 or .12 instead) but not a huge deal.

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

Opublikowany : 10/09/2018 7:15 am
bobstro
(@bobstro)
Illustrious Member
Re: Love at First Print


[...] .15 is technically not ideal on the mk3 due to the resolution of the z axis (use .16 or .12 instead) but not a huge deal.
Any multiple of .0025mm is fine for the Prusa Mk3. More info here.

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

Opublikowany : 10/09/2018 7:16 am
iamloremipsum
(@iamloremipsum)
Eminent Member
Topic starter answered:
Re: Love at First Print

Oh interesting! I will try that. I just used Prusa’s own .15 settings. Thanks!

Opublikowany : 10/09/2018 1:27 pm
Pathogen
(@pathogen)
Estimable Member
Re: Love at First Print

Any multiple of .0025mm is fine for the Prusa Mk3. More info here.

Thanks this should make for a lovely Sunday read!

Opublikowany : 10/09/2018 1:37 pm
RufusClupea
(@rufusclupea)
Reputable Member
Re: Love at First Print



[...] .15 is technically not ideal on the mk3 due to the resolution of the z axis (use .16 or .12 instead) but not a huge deal.
Any multiple of .0025mm is fine for the Prusa Mk3. More info here.

Speaking only from a "3D printing technology-challenged" noob POV, if I hadn't watched a benchy-load of videos on stepper motors on YT, I wouldn't have understood any of that thread. 😕

As it is, I think I may understand the gist...

Practically speaking, I can't imagine (myself) printing anything smaller than what I can realistically print with a .25mm nozzle (0.1mm layer height?) Looks like that .0025mm could be reduced (by 4) to .01mm. Is that even possible with FDM? (Rhetorical question--not expecting/looking for an answer... 😉 )

That's "MISTER Old Fart" to you!

Opublikowany : 10/09/2018 1:48 pm
bobstro
(@bobstro)
Illustrious Member
Re: Love at First Print


[...] Practically speaking, I can't imagine (myself) printing anything smaller than what I can realistically print with a .25mm nozzle (0.1mm layer height?) Looks like that .0025mm could be reduced (by 4) to .01mm. Is that even possible with FDM? (Rhetorical question--not expecting/looking for an answer... 😉 )
The gist is that you'll get better precision using an even multiplier of step motor resolution for your Z-axis, which translates to layer height. Any other value is approximated using microstepping which may not be as precise. I believe some older printers were incapable of microstepping. The "magic values" for layer heights were thus based on a resolution of .04mm, which meant layer heights of 0.04mm, 0.08mm, 0.12mm and so on yielded better consitency. Rounding done by slicers made the problem worse. Much of this arcane lore has been passed around, and there's often a misunderstanding that this applies to the Mk3. The resolution on the Mk3 is 0.0025mm, which means any value of X.XX is just as good as any other. To be precise, and value of 0.XX0, 0.XX25, 0.XX50 and 0.XX75 -- where XX are 1-2 decimal digits -- is a multiple of the Z-axis stepper motor rotation. So for all that, 0.04mm will work but 0.05mm is no worse. 0.16mm will work, but 0.15mm is no worse in terms of motor resolution.

I realize the thread I linked to is a bit wordy, but wanted to provide a bit more than just my word saying so. There are other references which, if I can find them, I'll post here. For now, know that any layer height consisting of up to two digits after the decimal point (0.XX) will work equally well on the Mk3.

And yes, below 0.05mm, things get pretty slow. If you need that resolution, an FDM printer may not be the best answer. I've had no problem printing at 0.04mm -- albeit slowly -- and I've read that 0.025 is theoretically possible. No idea what the practical minimum is on the Mk3 though. I'm already torturing myself with a 0.20mm nozzle and 17 hour test prints.

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

Opublikowany : 10/09/2018 2:46 pm
thrawn86
(@thrawn86)
Honorable Member
Re: Love at First Print



[...] .15 is technically not ideal on the mk3 due to the resolution of the z axis (use .16 or .12 instead) but not a huge deal.
Any multiple of .0025mm is fine for the Prusa Mk3. More info here.

I am neither a mathematician nor an experienced cnc machinist, and sean's rant goes a bit above my head about why prusa's calculator is wrong.

I did find a post from matterhackers suggesting prusa's own calculator is out of date or inaccurate somehow :/ seems like that would have been a much simpler answer.

Opublikowany : 11/09/2018 3:20 am
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