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Heavy VFA on a "no VFA" printer  

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Shushuda
(@shushuda)
Estimable Member
Heavy VFA on a "no VFA" printer

I am fed up with this issue, so I'm writing here. Anything printing at 20-55mm/s is showing excessive heavy VFA, worse than MK3S+. I cannot print at +55mm/s because it then shows a different artefact - uneven walls, orange peel. Every single printer has this orange peel on the walls at +40mm/s speeds. Yet I cannot avoid it by printing slower, because then I get VFA. On a "no VFA motors" printer, advertised in multiple places as such.

At first, as seen in a few posts of mine, I thought it's visible only on silk or under harsh light. I was WRONG. It's visible always. I just didn't print anything at the right angle, apparently. I did a few low poly prints recently and they all show VFA. This is ridiculous and NOT what was advertised.

This is what they advertise:

These are the prints I'm getting:

Postato : 24/09/2023 8:29 pm
Gummibjorn hanno apprezzato
ssill2
(@ssill2)
Noble Member
RE: Heavy VFA on a "no VFA" printer

it might be helpful to share some additional details.

Was this a factory assembled unit?

If not, was it a kit, or an upgrade from MK3S?   I just did two of these on my MK3S printers.

Do you have a test model we can try to print to see if we get the same result?

Postato : 07/10/2023 2:15 pm
Shushuda
(@shushuda)
Estimable Member
Topic starter answered:
RE: Heavy VFA on a "no VFA" printer

Details were shared in another VFA related thread on the forums.

It's a kit.

I've rebuilt it multiple times, swapped the Y belt, Y motor, Y bearings, Y pulley, new PETG parts, then new ASA parts, it's still consistently producing horrible VFA. No difference. Heavier than my MK3S+. Definitely heavier than what they advertise. They say "no VFA" and "eliminate VFA", yet the printer produces heavy VFA and the customer support themselves try to gaslight me saying these printers are actually not "no VFA" and they just say this to differentiate between MK3 and MK4. They literally confirmed in an email that they knowingly use misleading language and photos to market the printer as "no VFA" when it's actually having strong VFA by design.

"Oh, we say that but we actually mean something completely different and these promotional photos were taken in a very specific light, that's why you can barely see any artefacts on them. Why would you think those typical artefacts are gone on our printer when we literally use "no VFA" as a selling point? What gave you this idea?".

Also they constantly twist words, using "anti-VFA" (this phrasing doesn't exist in any marketing) to refer to the motors and using that as a leverage that "we didn't mean zero VFA, we meant a bit less" when the motors are clearly labeled "no VFA" and the marketing says they "eliminate VFA", not reduce. Also, my printer shows more VFA than MK3 so even this is a lie.

I am furious. This should be grounds for a lawsuit, this is false advertising. I want results from the photos Prusa itself shows as an ad for the printer and CS is telling me right in the face that this is not how the printer prints and that my prints are actually how it's supposed to look?! Then why are other people showing me their prints without VFA? What is going on here?

Click to see the whole message:

 

Posted by: @ssill2

it might be helpful to share some additional details.

Was this a factory assembled unit?

If not, was it a kit, or an upgrade from MK3S?   I just did two of these on my MK3S printers.

Do you have a test model we can try to print to see if we get the same result?

 

Postato : 07/10/2023 11:45 pm
Gummibjorn hanno apprezzato
Shushuda
(@shushuda)
Estimable Member
Topic starter answered:
RE: Heavy VFA on a "no VFA" printer

I'm trying to attach the gcode, it seems to be buggy

Postato : 07/10/2023 11:46 pm
ssill2
(@ssill2)
Noble Member
RE: Heavy VFA on a "no VFA" printer

can you zip and attach your .3mf?

Postato : 08/10/2023 1:16 pm
Shushuda
(@shushuda)
Estimable Member
Topic starter answered:
RE: Heavy VFA on a "no VFA" printer

Yes, I can't find the project file for the previous one, but it's the same as this one. The previous file was cut in half to make it print faster for testing, this one is full height. No other differences between the two.

I'm attaching a 3mf and gcode zipped together.

The VFA appear here:

Posted by: @ssill2

can you zip and attach your .3mf?

 

Postato : 08/10/2023 4:34 pm
ssill2
(@ssill2)
Noble Member
RE: Heavy VFA on a "no VFA" printer

cool, I can pull this and try a test print and see what I get

Postato : 09/10/2023 9:29 pm
ssill2
(@ssill2)
Noble Member
RE: Heavy VFA on a "no VFA" printer

ok I just sent it to the printer and printing ins some prusament PLA,  I'll let you know how it turns out

Postato : 09/10/2023 9:45 pm
ssill2
(@ssill2)
Noble Member
RE: Heavy VFA on a "no VFA" printer

I have about 15 minutes left on this print.   So far it looks great to me, but I'll attach pictures once it completes.

Postato : 09/10/2023 10:54 pm
ssill2
(@ssill2)
Noble Member
RE: Heavy VFA on a "no VFA" printer

So I was pretty happy with the result.  I used your settings from the .3mf.  I'm on firmware 5.0.0, prusa slicer 2.6.1.  The filament is viva la bronze prusament PLA.    During the course of my MK3S -> MK4 upgrades on both printers I replaced x and y rods and bearings(since my rods had grooves in them from wear).   I've been pretty happy with the MK4 upgrade thus far.   I'd probably do some tunings to this hide the seams, etc but I think it looks pretty good.   The prints I've done on the MK4 so far have looked great, and any ghosting etc I had on the MK3S(probably due to dry bearings, etc) are gone.   Hope this helps as a data point.

Postato : 09/10/2023 11:47 pm
Shushuda
(@shushuda)
Estimable Member
Topic starter answered:
RE: Heavy VFA on a "no VFA" printer

In the meantime, I've spent way too much time over the weekend on this, powered by sheer anger caused by that CS response.

I kind of fixed it? I mean VFA is still there, so I still consider this false advertising (no VFA and eliminated VFA mean zero VFA period, not "just reduced"). But it's greatly reduced. So CS was simply wrong - there was a clear issue with my printer. Furthermore they should educate themselves on VFA, as it is absolutely possible to reduce it to almost zero - look at Prorifi3D, they make MK3 motors with the sole focus on eliminating VFA.

Plus, you know, the whole marketing thing as I said already. It's bad that the marketing is lying, it's bad that the CS is trying to convince people with clearly faulty printers that their issues are not issues, it's bad all around and I did not expect neither such misleading advertising, but also that support response.

What I did? I had 2 Y motors on hand from a more recent batch, from a different resolved warranty claim. The first motor I had from the kit was super VFA prone - it's the one from those previously posted photos. I've tried one of those newer motors - very similar VFA, hard to tell the difference. I've tried the last one - and this one reduced VFA a fair amount. Next I've shimmed the motor mount to make the motor shaft even with the frame (the thermal pad twists this assembly), this is to make the belt centered on the pulley. And lastly, I've slightly overtightened my Y belt to around 102. To be clear - those belt changes did NOTHING to improve the previous motor's VFA. They did do something only with this one less VFA prone motor.

Just to mention, while I managed to reduce it to a state where I'm happy, I did spend the last few days looking at prices of the Trident LDO kit in various shops... I was very close to selling this printer and moving on. So yeah...

Here's how my print looks like now:

Postato : 09/10/2023 11:47 pm
Gummibjorn e ssill2 hanno apprezzato
Shushuda
(@shushuda)
Estimable Member
Topic starter answered:
RE: Heavy VFA on a "no VFA" printer

Hah, we posted at the same time. Thanks a lot for doing this print and giving me one more proof that my printer was just broken and support didn't want to acknowledge that. I think my current result is pretty close to yours now.

Posted by: @ssill2

So I was pretty happy with the result.  I used your settings from the .3mf.  I'm on firmware 5.0.0, prusa slicer 2.6.1.  The filament is viva la bronze prusament PLA.    During the course of my MK3S -> MK4 upgrades on both printers I replaced x and y rods and bearings(since my rods had grooves in them from wear).   I've been pretty happy with the MK4 upgrade thus far.   I'd probably do some tunings to this hide the seams, etc but I think it looks pretty good.   The prints I've done on the MK4 so far have looked great, and any ghosting etc I had on the MK3S(probably due to dry bearings, etc) are gone.   Hope this helps as a data point.

 

Postato : 09/10/2023 11:49 pm
ssill2
(@ssill2)
Noble Member
RE: Heavy VFA on a "no VFA" printer

yep no worries, I'm happy you got it working.  When I bought my MK3S printers originally I bought them fully assembled so I never went through the full build experience so I was a little afraid to do much tinkering with them.  When the two upgrade kits arrived I realized it was going to be nearly a full build so I strapped in and followed the build steps super carefully.   I'm glad I replaced the x and y rods/bearings since it gave me a better feel for what I'll need to do going forward for maint such as taking the bearings off and greasing them.

I must have lucked out since both my printers passed self-tests with minimal fuss.  I didn't use the phone app to do the belt tensioning, I just used the prusament petg printed tension tool and that worked like a charm.   Definitely caught myself wanting to skip ahead in the instructions but I forced myself to follow to the letter and I think that helped a LOT.

Anyway, great that you got it working your satisfaction.   Happy printing! 🙂   Now if my fully assembled 5 extruder XL would ever get shipped... 🙂

Postato : 09/10/2023 11:55 pm
Shushuda hanno apprezzato
Shushuda
(@shushuda)
Estimable Member
Topic starter answered:
RE: Heavy VFA on a "no VFA" printer

I spoke too soon. The issue is still there, with the new Y motor even worse than before. It just happens at a different angle now so I missed it on my test print.

Tldr, this went back to CS, but as a motor issue and to a different person. The VFA changing strength and placement with a Y motor change makes me think two things:

1. If changing the Y motor is the only thing that affected VFA - it is the source of the issue. I will pursue this.

2. All my Y motors are having more resistance when spinning the shaft manually with the motor unplugged than the X motors. They are also vibrating more. The original one was worse in this regard than both of my X motors and produced VFA. The newer Y motors are the worst, they feel like an entirely different motor. They're also identical to each other, which means it's kind of unlikely to be a single dud. They will verify this and I might send the motors back for inspection. Depends on their decision.

The fight continues.

Postato : 11/10/2023 6:15 am
ssill2
(@ssill2)
Noble Member
RE: Heavy VFA on a "no VFA" printer

Fingers crossed you get it sorted out!

Posted by: @shushuda

I spoke too soon. The issue is still there, with the new Y motor even worse than before. It just happens at a different angle now so I missed it on my test print.

Tldr, this went back to CS, but as a motor issue and to a different person. The VFA changing strength and placement with a Y motor change makes me think two things:

1. If changing the Y motor is the only thing that affected VFA - it is the source of the issue. I will pursue this.

2. All my Y motors are having more resistance when spinning the shaft manually with the motor unplugged than the X motors. They are also vibrating more. The original one was worse in this regard than both of my X motors and produced VFA. The newer Y motors are the worst, they feel like an entirely different motor. They're also identical to each other, which means it's kind of unlikely to be a single dud. They will verify this and I might send the motors back for inspection. Depends on their decision.

The fight continues.

 

Postato : 11/10/2023 11:40 am
Shushuda hanno apprezzato
Justin
(@justin-3)
Trusted Member
RE:

Not hijacking this thread for myself but I don’t think you’re alone. I have over 21 days of print time on my MK4 and while I tried to initially ignore the artifacts, I no longer can. I have spent hours troubleshooting with printing slower, faster, hotter, cooler, etc., have tightened and loosened belts, shimmed the motor to fix the tilt caused by the thermal pad, even tried replacing the pulley with a spare from a previous Voron build. Nothing helped and I finally reached out to support. They were stumped and had to take the discussion offline to involve other people. The photo below shows the issue that is only present on the Y axis. Waiting to hear back from support but don’t know where else to turn out what else to try.

Postato : 11/10/2023 12:00 pm
Shushuda hanno apprezzato
ssill2
(@ssill2)
Noble Member
RE: Heavy VFA on a "no VFA" printer

Given all the supply problems they've had, it wouldn't be out of the realm of possibility they got some bad motors.   I'm curious if they can narrow it down to a particular batch.   My two MK3s -> MK4 upgrades have been working flawlessly so maybe I got lucky and the motors that were included were not from the same batch.  I hope they get you guys sorted out.

Postato : 11/10/2023 12:05 pm
Shushuda
(@shushuda)
Estimable Member
Topic starter answered:
RE: Heavy VFA on a "no VFA" printer

I've put one of my X motors in place of Y (so now the printer has two X motors) and routed the cable weirdly just to reach the plug. Both of my X motors are pretty smooth, way better than any of the Y motors.

This is one of my test prints, printed with the first Y motor (the one from the kit), the print changes speed each 1cm to show how it affects VFA:

And this is the print I did today with two X motors. Results speak for themselves:

Postato : 11/10/2023 12:13 pm
ssill2
(@ssill2)
Noble Member
RE: Heavy VFA on a "no VFA" printer

I sure hope prusa makes this right for you guys.  I'd be very disappointed if they didn't.  And if this is larger problem with a big batch of motors I hope they'd come clean and just let folks know.

Postato : 11/10/2023 12:23 pm
Gummibjorn e Shushuda hanno apprezzato
mmaj
 mmaj
(@mmaj)
Active Member
RE: Heavy VFA on a "no VFA" printer
Posted by: @justin-3

Not hijacking this thread for myself but I don’t think you’re alone. I have over 21 days of print time on my MK4 and while I tried to initially ignore the artifacts, I no longer can. I have spent hours troubleshooting with printing slower, faster, hotter, cooler, etc., have tightened and loosened belts, shimmed the motor to fix the tilt caused by the thermal pad, even tried replacing the pulley with a spare from a previous Voron build. Nothing helped and I finally reached out to support. They were stumped and had to take the discussion offline to involve other people. The photo below shows the issue that is only present on the Y axis. Waiting to hear back from support but don’t know where else to turn out what else to try.

[..]

I am having the same issues, X and Y axis - belt tension is ok.

What did Prusa support tell you? Were you able to solve it?

Postato : 26/10/2023 1:30 pm
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