My observations after about a week with the MK3  

Re: My observations after about a week with the MK3

Some of these are known issues.

See here: https://shop.prusa3d.com/forum/original-prusa-i3-mk3-f30/mk3-power-supply-clicking-t12374.html . The official word is that this is a cosmetic issue.

Someone made a nice fix for this: https://www.thingiverse.com/thing:2740715 .

There was a batch of bad rods that went out. If you can hear the bearings grinding on the rods I would be concerned that you got one of the bad ones. Maybe contact support to see if they'll send a replacement. See here: https://shop.prusa3d.com/forum/original-prusa-i3-mk3-f30/scratched-rods-from-linear-bearings-t12826.html .

Good idea, but would it tell us anything more than the self-test?

This is something reasonable people can disagree about. IMHO it's probably better to err on the side of making it harder for novice users to break stuff.

Isn't this intentional, because the dimensions of the printer can shift slightly as they warm up?

Without knowing the reasons for the decision, it's hard for me to second-guess the design choice. Maybe at the time Prusa felt the Aero wasn't proven, or the parts were in short supply, or who knows?

There is a large pile of foulups, particularly in the printed parts. It's just sloppy work. I think things will get worse over the long term due to a combination of switching to PETG and just plain mistakes.

The basics are here and if someone put some solid, honest engineering work into fixing this stuff, this will turn out to be a really good printer.

But right now it's got some fairly serious teething issues.

My attitude is that if you buy a kit printer, you're going to get a kit printer with all that implies. This is true even if you buy your kit assembled. The upside is that you get access to advanced features at a very attractive price. But when you live on the bleeding edge you're sometimes going to get cut.

There have definitely been some teething pains, but Prusa has been fairly good about addressing problems as they arise.

Re: My observations after about a week with the MK3

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[*]Choice of entire extruder questionable; should have jumped straight to the Aero
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I think the Aero is not a dual-gear extruder so it may perform worse than the MK3 one. One of the interesting aspects of all the Prusa designs is that it represents the best you can do with FDM parts and people can always try to make it better and share back to the community. If you prefer the Aero it should be possible to make a mount to retrofit it.

Would you consider trying to prioritize the items on your list? I'd put the belt rubbing of the X axis fairly high. I am working on some new parts to try addressing this.

Re: My observations after about a week with the MK3

Amen to Y axis ringing, I also have slight X axis ringing as well. See pages 17-20 of the "Poor Print Quality" thread for details, we think it's firmware/stepper related.

It sucks. Deadset wish I hadn't bought the mk3.

Re: My observations after about a week with the MK3

So that the PSU skews the frame is a fact. I had always slightly skewd xy afzer calibration. I built an enclosure and moved the PSU outside of the enclosure did a calibration amd it says everything is perpendicular ...

Re: My observations after about a week with the MK3

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It sucks. Deadset wish I hadn't bought the mk3.

Really, out of curiosity, what do you believe would be a better choice? Feel free to PM if you don't want to publicly post. I'm genuinely wondering what better choices there are.

Re: My observations after about a week with the MK3

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It sucks. Deadset wish I hadn't bought the mk3.

Really, out of curiosity, what do you believe would be a better choice? Feel free to PM if you don't want to publicly post. I'm genuinely wondering what better choices there are.

Honestly I don't know, but a friend of mine has a $150 Monoprice Mini Delta and is stomping my mk3 print quality in regards to the ringing issue.

Re: My observations after about a week with the MK3

Some of these are known issues.

This is something reasonable people can disagree about. IMHO it's probably better to err on the side of making it harder for novice users to break stuff.

How would you cold pull if it won't let you unload at 170c or slightly lower? that's the point of a cold pull, and it's recommended when switching filaments and filament types.

Re: My observations after about a week with the MK3

The Bad:

Before I begin: I bought my printer pre-assembled. Don't bother trying to blame any of this on "my building" of the printer. Totally worth the money just to head you guys off at the pass.

My MK2s PS clicks too, you can't hear it because the printer is loud. other printer PSU's are usually a 300w+ variant with a fan, they mask their clicking too. it's harmless, i have a few fully CE certified things around that make hums, clicks or high pitch 20hkhz eeeeeeee sounds (like wireless charging stuff usually...)

Since the printer is silent you'll hear more things, i've run TMC2100's on other printers for a while and you'll hear things you didn't think were there before.

That being said, i have Misumi bearings and rods and they're the loudest part of the printer usually, same old sound.... Igus or V-wheels is the quietest solution and would easily bump up the cost of the machine since they're not cheap. if you're rolling hard steel balls over steel rods, they will make noise regardless, especially when everything else is quiet. plus the frame resonates a lot making it louder than X. i found the prusa bearings to have excellent tolerance actually.... just not quality rods.

PETG is questionable but probably to reduce warping, i don't see an issue if there is QC on it. ABS usually has a nicer surface finish due to it's viscosity... less ringing or vibration artifacts are transferred to the print with ABS (depending on temps tho). so you get pretty consistent layer lines and a more matte look too which further hides any imperfections. But it does have a higher failure potential so i don't see why not PETG if it's dialed in properly.

Re: My observations after about a week with the MK3

Someone made a nice fix for this: https://www.thingiverse.com/thing:2740715 .

Interesting. Actually, that just gave me a different idea. Need to look at it when I get home...

There was a batch of bad rods that went out. If you can hear the bearings grinding on the rods I would be concerned that you got one of the bad ones. Maybe contact support to see if they'll send a replacement. See here: https://shop.prusa3d.com/forum/original-prusa-i3-mk3-f30/scratched-rods-from-linear-bearings-t12826.html .

I already gave a longer opinion on the bearings elsewhere (multiple elsewheres), but it's still a design issue. Don't get me wrong -- switching to the extrusions got them a lot lot lot lot lot closer to the end goal. They just need to finish the job.

Good idea, but would it tell us anything more than the self-test?

Yes. I may make a longer post regarding this (I kind of already have, but it's way back there and a little esoteric), but what matters is the end result, not the proxy. The auto-cal is a proxy. So just lay down a big square edge so the guy assembling the printer can immediately throw a square against it and measure it, and then the customer can do the same thing when he gets it. I don't think it's an unreasonable ask; they're already laying down the test print, so just make sure it's useful.

This is something reasonable people can disagree about. IMHO it's probably better to err on the side of making it harder for novice users to break stuff.

I've been unloading at 170C for like 4-5 years without issue. When I unload at 170C, I manually set that hotend temp. I.e. you have to specifically ask for it. Most newbies will go straight for the "preheat" selections instead. I'm pretty sure I'm not the only one who unloads at 170, so the option should be available somewhere even if you have to bury it to protect the newbs. I'm not asking for 25C, or 100C or 160C. But 170C should be allowable somehow.

Isn't this intentional, because the dimensions of the printer can shift slightly as they warm up?

Sorry, I should have been more specific. I still let the heated bed go to full temp, but I have seen no good reason to probe at full temp. 170C is still good enough to soften every filament that I've used. Probe at 170C, return to home +Z15, go to full temp, -Z15, start the rest of the process. Been doing this for 2 years with my Mk2.

Without knowing the reasons for the decision, it's hard for me to second-guess the design choice. Maybe at the time Prusa felt the Aero wasn't proven, or the parts were in short supply, or who knows?

Then don't second guess it.

My attitude is that if you buy a kit printer, you're going to get a kit printer with all that implies. This is true even if you buy your kit assembled. The upside is that you get access to advanced features at a very attractive price. But when you live on the bleeding edge you're sometimes going to get cut.

You can't have it both ways. You have made multiple arguments about making this printer safe for noobs, implying this is a noob printer.

But when the chips are down, you pull a 180 and start calling this some sort of advanced bleeding edge thing.

So which is it? If it's a noob printer, then it shouldn't cut me.

If it's an advanced printer, then let me have my advanced options.

Or the third option is: this whole attitude is irrelevant. (This is the one I would go with.) These are all technical problems, and they all have technical solutions other than essentially "caveat emptor lol".

I think the Aero is not a dual-gear extruder so it may perform worse than the MK3 one. One of the interesting aspects of all the Prusa designs is that it represents the best you can do with FDM parts and people can always try to make it better and share back to the community. If you prefer the Aero it should be possible to make a mount to retrofit it.

I'm not convinced the dual-drive is really necessary, especially for the stock hotend.

On the other hand, I am convinced that all the damn extruder parts need to actually line up correctly and hit some pretty tight tolerances.

Would you consider trying to prioritize the items on your list? I'd put the belt rubbing of the X axis fairly high. I am working on some new parts to try addressing this.

I'll try, but I'm not sure we're allowed to edit posts after a certain amount of time...

My MK2s PS clicks too, you can't hear it because the printer is loud. other printer PSU's are usually a 300w+ variant with a fan, they mask their clicking too. it's harmless, i have a few fully CE certified things around that make hums, clicks or high pitch 20hkhz eeeeeeee sounds (like wireless charging stuff usually...)

Since the printer is silent you'll hear more things, i've run TMC2100's on other printers for a while and you'll hear things you didn't think were there before.

With no motors running and no ambient noise, my Mk2 does not click while warming up the print bed.

With no motors running and no ambient noise, my Mk3 clicks when warming up the print bed.

It's not appropriate. Again, this is only a week for me, but we'll see how the stats play out over the long term and many more other participants in the PSU game. It's only hindsight if you didn't see it coming.

PETG is questionable but probably to reduce warping, i don't see an issue if there is QC on it. ABS usually has a nicer surface finish due to it's viscosity... less ringing or vibration artifacts are transferred to the print with ABS (depending on temps tho). so you get pretty consistent layer lines and a more matte look too which further hides any imperfections. But it does have a higher failure potential so i don't see why not PETG if it's dialed in properly.

PETG under heat and stress seems to fare worse than ABS.

I have a bad feeling about throwing this printer into an enclosure where I typically let the temp get up to 40C+ ambient.

I do not believe PR has actually tested this condition.