Multiple Issues - Really Need Help

[Ztannem 0]

Hello All, 

 

In need of some serious help. Please let me know if i should split this into multiple threads.

I recently started 3D printing with my Ultimaker 3 Ex and I have ran into quite a few issues with my first few prints. The first issue was when I tried printing with PVA support. The result is on the first few pictures attached. My assumption was a plugged nozzle so I cleaned everything and when on to try a different print. This was the second one attached which I aborted about 10-20% of the way through due to what I am assuming is either underextrusion or some other issue causing the PVA to not attach to itself. Both of these were done with a 0.4AA Nozzle and 0.2 Layer Height.

 

I then decided to attempt the same prints again (Both the first and the second one). But run a test on Nylon support with it, I also wanted to try a quicker print so I went with a 0.8AA Nozzle and 0.4 Layer height. I know these are a lot of changes but I am really trying to learn my way around ideal centerlines through cause and effect.

 

Even though it maintained most of its structural integrity this print had quite a few issue's which I dont fully understand. I attached pictures of this last print. It looks like overextrusion or mistakes, leaving a substantial amount of material around and a less than desirable general quality of print.

 

Im at a loss on what I am doing wrong or what I am missing for all these prints. Any kind of help would be hugely appreciated.

 

Thanks a ton.

 

[gr5 2,167]

You have two completely unrelated issues.  Your PVA is underextruding badly.  Your black plastic (is it pla?  Or Nylon?  It doesn't look like nylon) has some zits.  I don't know if you care about those.  The overhangs on your part aren't so great because the PVA did almost nothing.

 

PVA can absorb water pretty easily.  If humidity is high, sometimes even in just the time it takes to do one print.  Ultimaker PVA takes longer to absorb water than some other brands but leaving it on your printer for a few days is much too long if humidity is higher than 60%.  Basically where 95% of humans live in the summer is too much humidity.

 

If the PVA has absorbed a lot of water it will snap crack pop and sizzle and you might see steam.  The PVA will be snowy white and less transparent.  Basically though if it is only *slightly* to wet it will look fine but won't print as well (similar to what I see in your photo).  I suspect you need to dry it.  I recommend putting it on the heated bed of the printer at 80C (no hotter!) with a towel over it for at least 2 hours to get the outer meter of filament (if you have a small print that only needs a meter or so of pva) and overnight to get most of the reel.

 

Then never leave it on the back of the machine even when printing - I keep it in a 2 gallon ziplock just open enough to let the filament out with a large dessicant pack (20 grams) that changes color when the desiccant needs to be reset (often).

[gr5 2,167]

Oh and the zits are sometimes associated with retraction but mostly with printing too fast.  If you want your parts to look prettier you have to have patience and set *all* the printing speeds to 30mm/sec and if that fixe things speed it up slowly from there.  You can play with the speed while it's printing in the TUNE menu but it's important that all the speeds are the same for the prettiest prints (no speeding up and slowing down as these cause under and over extrusion).

[Ztannem 0]

I will purchase some larger dessicant packs for the PVA and try it again after leaving it in an encolsed bag for a certain period of time. 

 

The black was Nylon. I reduced the speed and upped the temperature and it has resulted in substantially less zits and better print quality, thanks for the advice!.

[gr5 2,167]

Once the pva is "damaged" by water no amount of desiccant will help.  Or at least it would probably take months to get it dry again.  Including resetting the dessicant 5 or 10 times during that time period. Instead you must heat it on the heated bed overnight under a towel at 80C to get it back to "good as new".

 

[gr5 2,167]

5 hours ago, Ztannem said:

I reduced the speed and upped the temperature

Sounds good.  Higher temperatures tends to result in more stringing/leaking but if it worked I'd stick with what worked.