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Is this as good as it gets?  

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Patrick McNamara
(@patrick-mcnamara)
Estimable Member
RE: Is this as good as it gets?

 

Posted by: @benjiale

I'm not sure if I was clear enough about this and I can't seem to edit this now - but I feel like I expressed I saw this only once. I saw this several times - usually once every 1-3 layers in different spots. 

Seeing the problem?

So - I've been taking time to play with slicers (against my better judgment, I paid $59 for the upgrade to S3D v5 because I feel like I've tried everything else) and, I don't think I've eliminated it, but I have seen it, or what I think is it. I turned on the 'print perimeter lines first' setting in PS, and turned off Arcahane perimeter generator (just thought maybe I was getting thicker lines from that generator?). While the print quality hasn't improved from my initial review - I watched the first 15 minutes of the print very carefully and I think I have observed extrusion irregularities with my eyes... when I observed the printer printing the perimeter first, I would clearly see an intermittent thick filament extrusion followed by a very thin extrusion - very thin - almost like stringing... this would then resume regular extrusion about .05-2mm later. 

This certainly would point more towards the extruder and/or filament path.  You mentioned that you are using the filament holder that comes with the printer.  When using the filament holder, the tension will build on the filament until it causes the filament roll to move on the holder, then it will go slack and repeat.  It will be kind of hard to watch too things at once, but does the the thin extrusion line up with just before the filament spool moves?

I haven't used the spool holder in ages as I have my printer in an enclosure and have a set of spool holders on top with bearings.

I wouldn't expect the spool holder to be enough to make that kind of difference, but if the filament path is a bit tight elsewhere, like the PTFE tube is a little tight, then maybe its enough to cause some issues at certain points?  The extruder stepper is pretty strong, in my experience.  My printer has printed through some mildly tangled filament that I would have expected to cause problems.

If there is an extrusion problem, perhaps changing the test print might show it differently.  A print of a 75-100mm square, one layer (0.2mm) thick, might show things differently.  This is similar to first layer calibration prints, but in this case we aren't looking at the bed adhesion and squish of the first layer, but how how uniform the extrusions are.

Napsal : 30/12/2022 7:59 pm
RandyM9
(@randym9)
Honorable Member
RE: Is this as good as it gets?

Would the spool holder perhaps introduce friction which might cause this? I put it smack-dab in the middle of the printer. 

Doubtful. I don’t use the Prusa supplied spool holder because I didn’t like the way the spools rocked back and forth and sort of ‘thunked’ over when unwinding. It’s possible that if this is happening in your setup that filament tension could be changing if the spool is rocking back and forth a lot. 

I know it’s a pain but you could test this by manually manipulating the spool to prevent any uneven tension while printing. However, I think this is an unlikely cause.

Napsal : 30/12/2022 8:06 pm
BenjiAle
(@benjiale)
Active Member
Topic starter answered:
RE:

 

Posted by: @patrick-mcnamara

If there is an extrusion problem, perhaps changing the test print might show it differently.  A print of a 75-100mm square, one layer (0.2mm) thick, might show things differently.  This is similar to first layer calibration prints, but in this case we aren't looking at the bed adhesion and squish of the first layer, but how how uniform the extrusions are.

I printed the entire bed - first I cleaned it with dawn, then a wipe with 99% IPA. I printed at default speeds for the first few minutes, inching slowly up until I hit 80 mm/s. Here's various shots (one backlit) - while I'd say the default first layer speed was BETTER it was not without its faults - which increased in size and quantity as I hit 50 mm/s

 

Thoughts? I mean these look like what my surfaces look like - roughly. 

Napsal : 30/12/2022 9:51 pm
BenjiAle
(@benjiale)
Active Member
Topic starter answered:
RE: Is this as good as it gets?

With the hotend at room temperature, if you grab the nozzle, can you move it left, right, forward, back, or any other way? Do you notice any movement of the hotend while printing?

 

It's a good thought for sure - I have checked this with Prusa support, something they suggested. The heat block is solid, and there isn't any play I can feel / discover. I have not kept a close eye on the heat block or the hot end while it's printing to see if it's moving. 

Napsal : 30/12/2022 10:28 pm
RandyM9
(@randym9)
Honorable Member
RE: Is this as good as it gets?

Based on your single layer print, it doesn’t appear the hotend is wandering, at least to my eyes. The layer lines look pretty straight. Not what I would expect if there was something loose.

It looks more like the extrusions aren’t uniform, just as you’re seeing in the layer lines of walls in your other prints. This seems like it could be either an obstruction in the filament path or a stepper motor issue. 

Interested to hear what support has to say. I’ll think on this some and let you know if I come up with anything useful to try.

Cheers

Napsal : 30/12/2022 10:52 pm
BenjiAle
(@benjiale)
Active Member
Topic starter answered:
RE: Is this as good as it gets?

Hi there,

I thought I'd offer an update. I have worked with support 11 days, and there have been no improvements - actually, a degradation in performance and quality after doing what support intermittently tells me to do. I've been now working with tier two support, and they haven't been returning my e-mails - my last e-mail to them said - hey - what you guys told me to do either introduced new problems or made this one worse. They responded four days later, asking if the issue was resolved.

Honestly, after hearing so much about how amazing Prusa are, and how amazing their support team is... I'm at such a loss. I don't know if the team will be able to help, and bouncing ideas off of the chat support has been discouraged. I think that this is as good as it gets.... at least for me and this machine. 

Napsal : 10/01/2023 12:50 am
RandyM9
(@randym9)
Honorable Member
RE: Is this as good as it gets?

That is disappointing all around.

I would push support to send you a complete new hotend. It sounds like you’ve done about all you can and at some point Prusa should make it right under warranty.

I realize even this may not be an ideal solution as you still have to invest the time you to install it, but short of this, I’m not sure what more you can try. 

Thats just my opinion, I could be wrong.

Here’s hoping you get this sorted.

Cheers

Napsal : 10/01/2023 4:36 am
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