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Bossler

PLA & PVA... Print-Questions...

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So I'd printed a "Sylveon" (found on thingiverse) just for curiosity.

This thing needs a lot of support, so I used the delivered PLA & PVA.

IMG_4234.thumb.JPG.f12903560b21478351cfa63961ed4966.JPG

Well, the print did not end up all bad, even if there are some little defects.

 

What really does bother me with this print:

- the wipe tower got kicked off 1 1/2 hrs. before it finished

- the wipe wall does look really sh..

- and therefore quite some little defects are in the print

IMG_4225.thumb.JPG.0df4593865e9ea82fb7d81657c1130f1.JPG

Any suggestions regarding print settings for such an object?

Major problem was the wipe wall not really "sticking" - higher temp?

Layer height was 0.1mm, PLA-temp at 200°C, PVA temp at 220°C.

Edited by Bossler

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Over time, I got used to printing without a priming tower. It killed a lot of time and filament and it did get knocked over. Now, I rarely use an ooze shield. One of the setting you may want to check out is under support. Unhide the support settings that are not visible by default by clicking the little arrow on the side. In those settings you can find support horizontal expansion. It defaults to 3mm. That is why your figure got wrapped like a spider yummy.

 

The UM PVA material is unique in that it makes that silvery, crystalline looking construct. It has always made little squirrel nest parts no matter what I have tried. It also dissolves different from other brands in that it turns into alien snot. The other PVA I use just makes the water milky and dissolves much quicker. But, quicker dissolve means easier to suck the humidity out of the air.

 

I would also suggest playing with temps a bit. Maybe lower them just a bit.

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I put a new print on pause to take a few pics. I am having to reprint a model that you can see the aborted print behind it. The print was going quite well. So, why aborted? Well, da clumsy noob stuck his slow, old hands in the buildplate while it was printing to grab something and the printhead slammed into it. That knocked the x-y offset and, well, hasta lumbago to that print. But, you can see what I did. I also did not use a raft to stick it down. I used PVA slurry that I recycle from the prints to brush down. And, I used a PVA brim.

 

This is a close up of the new print. You can see that the supports are tight on the model by way of a 0.2 horizontal expansion on the supports. In the next pics you can see why it looks so far out from the tank because there are pokey outey things along the sides it is building support for. But the sides are clean and there are the squirrel's nest droppings.

CleanSides.thumb.jpg.4edee989ee44e3ab77d30f79590784b8.jpg

 

This pic you can see the almost completed tank that I messed up. This has only had the alien snot dissolved off, no post processing on the sides or anything. You can also see how much stuff there is poking out of the sides for the support to grow up to.

AbortedandNewPrint.thumb.jpg.538f8c302713dc576db916846fa848ff.jpg

 

Here you can see inside the new print and how the supports are starting on the inside for internal structures that poke out inside the vessel.

PVABuildingUpForInternalSupport.thumb.jpg.1bb9db4ff2a52e49f551d39c920ac83b.jpg

 

This model was/is being printed for my brother. He is a mechanical engineer and designs these type of pressure vessels for all over the world, but mostly the US. These are his files from Inventor I am printing from. That is why, instead of a solid model, it has internal structure with the pipe leads being printed in as if it was a real mini-version of the actual vessel he designed. A solid model would have been much quicker. But it is amazingly strong, clean and shows the workings inside and out should he want a cutaway print.

I printed the material at default temps for the PVA. The PLA was printed at 195°C. No speed changes. These are on the new printer and it is my big shakedown print to see how it does. The materials are the PVA and PLA that comes with the printer.

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Well, the wipe tower is one thing.

What really worries me is that the wipe wall was so bad.

This picture shows the lower area of the print:

BadWipeWall.thumb.jpg.44dbfcc398e829f35d2a4776af3137f7.jpg

 

When you look at it in detail you recognize that the layers did not stick well to each other from time to time.

The PVA was new & fresh from the sealed bag. No signs of humidity, no strange sounds from the filament.

I do not think this is related to the horizontal expansion of the support?

 

By the way, interesting print you did!

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What type of support pattern and how dense? Maybe slow down the speed too. But, the support horizontal expansion could really be brought in on such a model. Try about 0.2 on that.

 

Thanks for the compliment, but it is my brothers doing. I am just the output monkey  ;p

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Support was concentric 3d with dense support layer on top and bottom.

 

But again - the support worked fine so far.


What I worry about is why the ooze shield did not print well.

Looking at the marked areas, you can see that layers of the ooze shield did not follow the round outline but went straight instead.

Interestingly this recovered then on higher layers.

The printhead did actually follow the outline but the layer did not stick to the previous layer.

I'd like to understand why-

Z-Heigt should have been perfect and as the first layers did stick well, I do think that's not the issue.

I can only imagine a temporary drift of the temperature (likely a drop in temp if any)?

But that is hard to control/find out - if not any hidden logs might be available?

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I did a few tests with the ooze shield and decided to stick with a prime tower when really needed. Each test with an ooze shield ended up with a misprint. And having both prime tower and ooze shield seems a bit overkill for me anyway.

 

As a rule for the prime tower, I personally always move it towards the center right of the bed, and I give it a thickness of 3mm. Center left or center right will often be more flat that the corners, ensuring better adhesion, and 3mm thickness is enough to give it a good stability and ensure it won't be knocked over and ruin your print.

 

As was said above, PVA should be printed in thick layers, although in my experience it has shown an amazing ability to recover and do it's job even when the first layers had some problems. I had printed stuff that was quite tall, and the first 15-20 layers of PVA wouldn't stick in some parts, leaving some holes in them and such, then the layers would start sticking together again as the printer started to create the roof for support of parts sticking out, and it actually worked.

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Have you tried printing with all default settings? In the office here, I never see anyone using an ooze shield. I guess because it's not optimal. 

The default profiles work very good for Ultimaker hardware and materials, for most models at least. 

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On 27-1-2018 at 1:44 AM, kmanstudios said:

 

AbortedandNewPrint.thumb.jpg.538f8c302713dc576db916846fa848ff.jpg

 

This model was/is being printed for my brother. He is a mechanical engineer and designs these type of pressure vessels for all over the world, but mostly the US. These are his files from Inventor I am printing from. That is why, instead of a solid model, it has internal structure with the pipe leads being printed in as if it was a real mini-version of the actual vessel he designed. A solid model would have been much quicker. But it is amazingly strong, clean and shows the workings inside and out should he want a cutaway print.

I printed the material at default temps for the PVA. The PLA was printed at 195°C. No speed changes. These are on the new printer and it is my big shakedown print to see how it does. The materials are the PVA and PLA that comes with the printer.

 

Nice print @kmanstudios! Beautiful.

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