PVA use

[rbeddoe 0]

How has PVA been working for UM users? We have Ultimaker PVA and it's been good when users handle it properly. We've found the key is to keep it dry and to warm it up just before using it. Otherwise, it's extremely brittle and will wreak havoc with the bowden drive.

 

More interested in hearing how others have dissolved this material. We've used room-temperature water as well as warm water. Not too warm as to warp PLA parts, however. Still seems to take at least a day to fully dissolve from most parts.

[gr5 2,269]

I don't find it to be brittle.  Maybe you dried it a little too much.  Also I don't have to warm it up before use.

 

But I keep it in a 2 gallon zip lock with a LOT of dessicant.  And I recharge the dessicant about once per month.  Maybe 1/2 cup of dessicant.

 

I usually get impatient and keep poking at the part - I put it under water in warm water and try to pull some of the PVA off right away then I walk away and come back several times removing more and more PVA.  When the final layer is pretty thin - just a few mm thick I usually leave it overnight.  I've never had to wait 24 hours but 4 hours is definitely not enough either.

 

I change the water a few times in the first hour.  The water tends to be room temp for most of the time.  It's only warmer than that when I first fill the bucket and each time I think of it, I change out the water.

[Carbon 29]

PVA.......well.....

 

Cut a long story short, we've stopped using it. We now use "breakaway" with AA0.4.

 

Story:

The last straw was when the PVA broken and got stuck in the feed channels underneath the machine (just after the material bay loading points). The amount of times the material has broken and jammed inside the bowden tubes is unreal, as it feeds you can hear the cracking sounds of the material breaking.

 

Storage has always been within a sealed bag along with a bag of "Silica Gel", prior to using, we warm the material inside the machine, by laying it onto the print bed for about 1 hour @ 60°C.. 

 

It just given us a lot of problems and wastes a lot of time, for very little benefit.

 

What we have noticed using "breakaway" is that the parts are a little more accurate......

 

 

Edited March 31, 2021 by Carbon

[gr5 2,269]

Breakaway is fantastic.

 

You can also use PLA as breakaway if you are printing nGen.  This is my favorite combination.  It works so incredibly well and the quality of the result is fantastic.

 

I haven't had any trouble with PVA being brittle.  I was told it can get brittle if it's too dry.  I can bend PVA quite a bit and it won't break.  

 

I have a few spools and one is from when Ultimaker first sold their first UM3 (3 years ago?  4?) and it's still not brittle so I don't think it's "age" that causes this.  Maybe different formulations.

[Jman15x 4]

I only use PVA when the support in needed for an internal component or when printing with Nylon. Mine always cracks when being fed through the Bowden tubes, I will have to try heating it up first. Thanks for the idea! As for removal I find its easiest to remove 99% of it with pliers before it even goes into the water. Usually once you get it started the rest just peels away. 

[gr5 2,269]

This is news to me - cracking PVA.  Is this Ultimaker brand?  I wonder if they changed their formulation?  Or if it's just too dry?  Maybe instead of heating you should leave it out in humid air for an hour?

[meskan 0]

On 3/30/2021 at 4:17 PM, rbeddoe said:

How has PVA been working for UM users? We have Ultimaker PVA and it's been good when users handle it properly. We've found the key is to keep it dry and to warm it up just before using it. Otherwise, it's extremely brittle and will wreak havoc with the bowden drive.

 

More interested in hearing how others have dissolved this material. We've used room-temperature water as well as warm water. Not too warm as to warp PLA parts, however. Still seems to take at least a day to fully dissolve from most parts.

PVA is brittle for sure and overnight usually dissolves all of it or running water over it speeds it up

[meskan 0]

On 3/31/2021 at 3:22 PM, gr5 said:

This is news to me - cracking PVA.  Is this Ultimaker brand?  I wonder if they changed their formulation?  Or if it's just too dry?  Maybe instead of heating you should leave it out in humid air for an hour?

I just open a new pkg (Ultimaker) that i just received and to straighten it enough to feed into the feeder is a test of patience to not break it.  PLA, bends easily.

[gr5 2,269]

Wow.  This is again, news to me.  Ultimaker PVA has always been more brittle than PLA but not so bad that it would break while loading or break in the bowden.  I've never treated it gently.  Again, I'm told that this can happen if it gets too dry but I use a LOT of dessicant and regularly recharge the dessicant.  Around 1 Cup or 1/4 liter of dessicant per spool.

[meskan 0]

3 hours ago, gr5 said:

Wow.  This is again, news to me.  Ultimaker PVA has always been more brittle than PLA but not so bad that it would break while loading or break in the bowden.  I've never treated it gently.  Again, I'm told that this can happen if it gets too dry but I use a LOT of dessicant and regularly recharge the dessicant.  Around 1 Cup or 1/4 liter of dessicant per spool.

[meskan 0]

why ??

[gr5 2,269]

That's not a brittle issue.  when it's brittle it breaks in the bowden tube.

 

So PVA is very different from PLA.  It's harder to print.  It doesn't stick to itself so amazingly well like PLA.  So that could be normal in your photo but I think that is probably PVA that absorbed too much water.  LIke i said above, I keep it with 1/4 liter (one cup) of dessicant at all times.  I NEVER leave it overnight on the printer, etc.

 

One sign the PVA is too wet is it snaps and pops and hisses and you can actually often see steam coming out at the nozzle tip while it prints.  The PVA ens up being snowy instead of clear (like this photo) because it has tiny steam bubbles embedded (hence the snowy look).   If it's only a "little" wet you won't notice the noise or steam but it will still be showier than usual.

 

When PVA is wet like this it expands too much and so it overextrudes.  Enough to get lots of stringing and other issues.

 

It's easy to fix with heat.  In cura look up how many meters of PVA are needed for your print.  Unspool that much, place on the heated bed, put the spool on top (no need to cut the PVA).  Put a towel over all that and another blanket on top of that and heat at 70C for 4 hours.  That should be enough to get you going on your print.  To dry the whole spool, dry it for 24-48 hours (not necessarily all at once).

 

Going forwards keep it in a 2 gallon zip lock with LOTS of dessicant.  And recharge the dessicant every month.  I buy it in liter jugs and store it in a container with a lid that stops the dessicant from coming out but allows air exchange.  I use color changing dessicant that can be reheated (dried) in the microwave.

 

[Kbeer87 0]

On 3/31/2021 at 11:59 AM, Carbon said:

PVA.......well.....

 

Cut a long story short, we've stopped using it. We now use "breakaway" with AA0.4.

 

Story:

The last straw was when the PVA broken and got stuck in the feed channels underneath the machine (just after the material bay loading points). The amount of times the material has broken and jammed inside the bowden tubes is unreal, as it feeds you can hear the cracking sounds of the material breaking.

 

Storage has always been within a sealed bag along with a bag of "Silica Gel", prior to using, we warm the material inside the machine, by laying it onto the print bed for about 1 hour @ 60°C.. 

 

It just given us a lot of problems and wastes a lot of time, for very little benefit.

 

What we have noticed using "breakaway" is that the parts are a little more accurate......

 

 

 

I had the same on our S5 Pro. We have switched to using BVOH for dissolvable support material, since then no issues

[gr5 2,269]

Sometimes the support material is in a cavity such that breakaway won't work but such that water can get in there.

 

But I have to admit I don't use support very often.  I try to design everything such that no support is needed.

[kmanstudios 1,120]

At the risk of sounding heretical, I do not use UM PVA much due to the cost. I use the Matterhackers MH build PVA. Dissolves much, much quicker, is not brittle at all and prints well. It does have all the other drawbacks of regular PVA though. Moisture issues, storage, etc. A spool of UM PVA is about $80 US and a 1 Kg spool of MH build PVA is about the same cost.

 

I have found that the Breakaway material can work in some surprisingly delicate sculpts, but it really grabs onto the printing material it is supporting. It also works rather well to print the Breakaway at the main interface points and the (say...) PLA or TPLA in the middle parts of the support. (that is why you have so many extruder choices in the support tab).

[geert_2 558]

On 3/31/2021 at 3:37 PM, gr5 said:

...

You can also use PLA as breakaway if you are printing nGen.  This is my favorite combination.  It works so incredibly well and the quality of the result is fantastic.

...

 

This method is new to me, but it could obviously have great potential.

 

How well does NGEN bond to the PLA, and how well is it removable? And the other way round, PLA to NGEN?

 

Does this also work for PET, CPE, etc.?

 

[gr5 2,269]

I don't know about other materials.  I'd guess it works fine for PET/PETG/CPE as I think those are almost the same thing as nGen but I don't know. 

 

It sticks nicely but after printing you pull with a bit of force and it pops right off.  I've only ever printed PLA support "touching buildplate" so I don't know how well it works on top of nGen.  I use off-white nGen and black or red PLA and there is often no color mixing at all.  But also often you can see the tiniest bits of color here and there (doesn't matter for me as these complex surfaces are deep within the part where a customer can't see).

 

And as you already know - the quality of PLA as support is 100X better than the quality of PVA as support.  Nice, smooth finish (obviously - it's PLA so it's great).