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OlivierV

PVA bubbles

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Hi, I use an UM3, Cura 3.0.3 with default settings.

When I print some PVA I get this:

PVA_bubbles2.JPG.a1f0c56f8d6ad96af8405d31fc3a6b71.JPG

It looks like bubbles in the filament. Before printing the filament is perfect and I store it in a dry storage (plastic box with moisture-absorbing desiccant packs in it).

Sometimes while printing I can hear some pops.

I looked at the other topics about PVA and the response is not clear.

As anyone already solved this issue?

Thank you!

PVA_bubbles2.JPG.a1f0c56f8d6ad96af8405d31fc3a6b71.JPG

Edited by Guest

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Yep

This is moisture. There is only so much you can do.

When you print is the spool covered or fitted to the back?

Basically you know boiling water creates steam, well as we print twice as hot compared to boiling point the transition is very fast. This can lead to the now gas form of the water to get trapped if the amount is very small. When the amount of moisture is above a certain amount the amount of gas expand where it bursts out of the plastic and that’s the pop.

There are printable solutions that encase the PVA whilst printing and contains moisture absorption (latter isn’t printable) I have designed one and is on youmagine and thingiverse. It’s bright orange.

I have designed something better but haven’t tested it yet. But will be available once I have.

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keeping the pva ALWAYS in a closed box with moisture absorbent, also when printing, really helps. I uise a simple cheap box with a printed spool holder;

https://www.youmagine.com/designs/drybox-for-pva-ultimaker3

There are also commercial boxes available but they really don't do more than any plastic container;

 

 

The one you linked to is nice though. I got it just to save time and materials in making the same thing. But, it was the built in thermo-hygrometer that sold me. And, it comes with rechargeable desiccant.

I just started using it with the PrintDry system and it has made a world of difference in how well it prints now with PVA.

This is where I go in depth on both products and my experience so far.

I am currently drying out some PC materials and will continue to dry out others. I just put them into the PrintDry and 'slow cook' them on lower than normal temps.

It can also be mentioned that the PrintDry can be used as a filament spooler, but I want to be able to switch out filamenst for printing without disturbing the drying process.

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Yep

This is moisture. There is only so much you can do.

When you print is the spool covered or fitted to the back?

Basically you know boiling water creates steam, well as we print twice as hot compared to boiling point the transition is very fast. This can lead to the now gas form of the water to get trapped if the amount is very small. When the amount of moisture is above a certain amount the amount of gas expand where it bursts out of the plastic and that’s the pop.

There are printable solutions that encase the PVA whilst printing and contains moisture absorption (latter isn’t printable) I have designed one and is on youmagine and thingiverse. It’s bright orange.

I have designed something better but haven’t tested it yet. But will be available once I have.

Hi rebekah_harper, thank you for your response. When I print my PVA is on the classic spool holder. It is true that between two prints I do not always store it back in my storage box.

Thank you for your clear answer.

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keeping the pva ALWAYS in a closed box with moisture absorbent, also when printing, really helps. I uise a simple cheap box with a printed spool holder;

https://www.youmagine.com/designs/drybox-for-pva-ultimaker3

There are also commercial boxes available but they really don't do more than any plastic container;

Hi Ultiarjan, thank you for this idea.

I will build or buy myself a box like this.

Thanks a lot.

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Yep

This is moisture. There is only so much you can do.

When you print is the spool covered or fitted to the back?

Basically you know boiling water creates steam, well as we print twice as hot compared to boiling point the transition is very fast. This can lead to the now gas form of the water to get trapped if the amount is very small. When the amount of moisture is above a certain amount the amount of gas expand where it bursts out of the plastic and that’s the pop.

There are printable solutions that encase the PVA whilst printing and contains moisture absorption (latter isn’t printable) I have designed one and is on youmagine and thingiverse. It’s bright orange.

I have designed something better but haven’t tested it yet. But will be available once I have.

Hi rebekah_harper, thank you for your response. When I print my PVA is on the classic spool holder. It is true that between two prints I do not always store it back in my storage box.

Thank you for your clear answer.

Glad you found it helpful.

I tend to print a lot with PVA and found that regular cleaning is required. the need to get used to the feel of the pressure when putting PLA through for cleaning is important. once you know how it feels when the nozzles is clean will help you gauge when you can stop cleaning.

I have applied a few measures and found that it only minimises and doesn't solve the entire problem. but I have only had one blockage for the last month and a half.

check out FOOD DEHYDRATOR, a stange but effective idea. it will make drying out your filament easier.

regards

Rebekah Anderson

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Indeed you can get a food dehydrator on amazon or wherever pretty cheap, you may need to adjust the plastic parts to make filament spools fitting.

At a bit higher price there are also units on the market (basically the same machine) specifically for the purpose of drying filament, so a good choice if you have more money than time :)

https://www.makerpoint.nl/nl/printdry-filament-dryer.html

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that dry box looks exacly like a food hydrator lol. not sure what they actually did to get there.

there is also this

PolyBox

a more unique design.

I actually have both of those.

For the Printdry system, it is spaced to hold two or more spools, so, taller 'cabinets' so to speak. There is also a hole in the side you can use to allow it to also be used as a spooling device.

A decent food dehydrator will cost around that price point, depending on the quality you want. Some way lower, some way higher too. But, I am sure it is just modified tech, with most modifications being to the size and design of the trays.

The Polybox is great too. I cannot believe how much better the PVA is printing now. Still a bit of cleanup, but nothing bad. And it prints so solid now....no more webby type of supports.

So, why the two systems> Well, sometimes a filament container can get ripped in shipping (Had it happen recently on two spools of PVA) because, not everybody uses a sealed box. Or, the storage I have used was not sealed as well as I thought. So, Printdry cooks out any moisture without taking up valuable print time by doing so on the printer and the polybox keeps it all dry while printing.

And, maybe I had a bit more money at the moment than I had brains.....Of course, 'anything' more than brains is mostly the case anyway....:p

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that dry box looks exacly like a food hydrator lol. not sure what they actually did to get there.

there is also this

PolyBox

a more unique design.

just to be clear..... the polybox is just a box with desiccant bags, good for prevention, but does not do anything more than any plastic container. It can not be used to actually dry out filament that already absorbed to much moisture.

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just to be clear..... the polybox is just a box with desiccant bags, good for prevention, but does not do anything more than any plastic container. It can not be used to actually dry out filament that already absorbed to much moisture.

It is a little more than just a box. It gots da bowden tubes to guide the filament and the hygrometer is nice to keep an eye out on how moist the environment and the built in rollers to all for easy spooling.

But, you are right, it will not dry out filament that is already soaked.

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