Printing with PVA

[tyler_farrell29 0]

Last week i decided to order some 3mm PVA (polyvinyl alcohol) filament to use in my ultimaker for a research project im working on. I bought the spool from UltiMachine, although i belive that it is originally intended for a MakerBot printer, but since its 3mm i figured it should work fine. Since there is not alot known about this material i figured id share my experience with it, with you. The benefit of this material is that it is water soluble so it perfect for mold making, and other things of the sort. The material is advertised to have an extrusion temperature of 160-175 degress celcius. While it will extrude at this temperature ultimaker has a built in extrusion failsafe that prevents it from extruding under 180 celcius so that it wont damage the machine, so nothing will print. After a bit of research i found that if you add a "M302" command line in the start .gcode will override this (be careful and dont forget that you added this so you dont damage your machine). Even after this though it still wouldnt work!!! i messed around for 3 days trying to find the correct procedure and settings to get it to work and this is what i found. Note: although the setup is somewhat irrational i prefer to keep things like this so i know for sure that it works, rather than try and compensate for it within the initial setup. You actually have to print it at 206 degrees celcius! The material is actually supposed to burn at this temperature so either something is wrong with my printer, the batch of PVA i got, or this is just how it works... maybe 160 celcius works for 1.75mm filament but it doesnt for 3mm. The material solidifies before it even has a chance to adhere to anything. MAKE SURE THE FAN IS OFF! The material is very delicate and will be blown off course by the fan, and again will harden before it can adhere to anything. PRINT VERY SLOW!!! i have it set to print at 10mm/s and even then i only run it between 30-50% on the printer. So be prepared for these prints to take a long time! And always print with a raft... And now here comes the fun stuff, the actual procedure which will drive you crazy!!! heat the printer to 206, and the flow to 120%, and manually turn the extruder by hand to flow a bit out, start the print and make sure you keep the excess flow off to the side. As the print begins make sure you, by hand, or by tweezers/tool, follow the extruder head and push the material into the bed to make it adhere... trust me... carefully watch the printer and make sure everything goes smoothly. it will probably mess up the first 5-100 times but dont get discouraged, youll figure it out. once the print is at about 1-2mm height you then need to increase the flow rate to 200%! this is because for some reason after 2mm it will put holes in your print due to lack of material, but trying to do the whole print at 200% will turn the base into a ball of GOO! After this just be sure to watch it carefully, and trust me when i say dont try to rush it... its going to take a while, so sit back, relax, cue up a show to watch or make some food, youre in for a ride! The part in the picture took an hour and a half to make. With PLA it took 15 minutes. Ive included addtional screen shots of the initial settings to so that you can replicate them. Note: im using cura 13.04 but only because its the only version capable of making the part i wanted, new cura doesnt like to make cylinders with the wall thickness extruder to the extruder nozzle size. Anyway i hope you enjoyed reading this and that this helps you. I know it wouldve helped me!

 

[illuminarti 18]

Thanks for sharing your experiences here! I haven't tried PVA yet, but it's on my list :-)

 

[nick-foley 5]

Wow, disappointing to hear that PVA is such a nightmare to print with. I've been having fantasies of setting up a nice dual extrusion head with PVA support that I could dissolve away and make my life easier... but now I'm second guessing that dream.

A lot of what you describe sound like underextrusion problems... And they remind me of problems we encountered when using the ultra-miserable Ultimaker Black PLA. Have you tried upping Cura's default pre-extrusion so you don't have to do any hand cranking of the extruder? When we set that to pre-extrude 15mm, we got much more consistent starting results. Also, having it print a huge number of skirts/brim (10-20) would also prime the extruder pretty well. Another thing that would help with the first layer was doing micro-adjustments to the bed screws during the first layer of printing, essentially raising the bed up into the nozzle until the layers were forced to stick.

I'd love to get a small amount of PVA to test out. Is there anywhere that you can purchase less than a full roll?

 

[philipyeah 0]

Hello, this thread is though old enough, I need the advice indeed, for I am trying to print something with PVA but with great problems.

1. it seems that PVA is difficult to stick on the glass plate, even if with glue (my printer is ultimaker 2). I set the temperature from 60 to 90 degree celcius, but none of them could let PVA stick on the plate. The print temperature was set as the suggested, at 206 degree celcius, and other settings were also followed by tyler_farrell29. Is there something wrong that can explain why my PVA not sticking on the plate?

2. the second issue was that the nozzle stop extruding PVA after printing for a while, this really confused me, has anyone an idea about that?

Thank you guys in advance!

Ye

[SandervG 1,518]

 

@foehnsturm, do you have some tips for @Philipyeah?

[foehnsturm 969]

Servus @philipyeah,

You might want to have a look at this topic https://ultimaker.com/en/community/20293-any-experiences-with-dual-extrusion-and-pva

In short, PVA is somehow a pain to print with. New variants that recently emerged like Scaffold are easier to handle (but still demanding).  If I run into printbed adhesion issues adding a thin coat of the well-known wood glue water mix usually helps.

And yes, I'm witnessing extrusion inconsistencies every now and then as well (now idea why). However not a complete stop. I assume, the speed being too high, therefore too much back pressure and the feeder grinding the (quite soft) PVA filament.

Edited June 3, 2016 by Guest