Trouble printing with soluble supports (PVA or Verbatim BVOH)
Hi All!
I received my 2-tool XL a couple weeks ago and have been pleased with it overall. However, I am still struggling to get the settings right when printing with soluble supports. I must add that I have a couple MK3S+'s with MMU's on them and have been successful printing with PVA for well over a year now. My main problem seems to be with the wipe tower and a lack of adhesion when using PVA. The lack of adhesion on the wipe tower causes filament to ball up on the nozzle and then drag over the part. I have had no issues when doing multi-PLA prints, I only have issues when attempting PLA-PVA prints. Here are some examples of my wipe towers:
Here is what I have tried so far:
1. Temperature changes - I noticed that the default profile with a 0.6mm nozzle for PVA has a printing temperature of 210 C, which is significantly higher than what I generally use on my MK3's (195 C). At this temperature, I was struggling to adhere to the PLA on my test print. I increased the temperature in increments of 5 degrees until I achieved somewhat better adhesion, which was around 220 C. However, at this high of a temperature, the PVA oozes a lot and makes the wipe towers much worse.
2. Wipe tower location - I've found that placing the wipe tower between the printed part and tool storage location can help in increasing the quality of the prints as most of the material that does not adhere to the wipe tower just falls on the build plate.
3. Wipe tower width - The default wipe tower width is 60mm which did not seem like enough length for the BVOH to adhere. I've doubled it to 120mm and that does seem to help.
I feel like if we had the ability to change the speed at which the wipe tower is printed, this problem would not exist. I am very confident that if we could slow the printing speed for the wipe tower, the adhesion for the PVA with increase. Has anyone else run into this problem? If so, what settings did you use?
Thanks!
RE: Trouble printing with soluble supports (PVA or Verbatim BVOH)
I never use PVA. Way too much trouble. Instead I always use PLA for supports and print in PETG with supports set to soluble and to only print supports from the bed only and not on the printed part.
Also, I never use the prime tower. I set my temps correctly I.e., not near as hot as Prusa did in their presets. This cuts way back on drool. I also set the “Retraction when tool disabled” to 11mm to retract out of the melt zone when the tool is parked. Works like a charm thanks to the integrated thermal tube design on the new nozzles. I’m getting great results.
use PLA for supports
Not an option for print-in-place seperators (OK, it might work for trinkets) and reducing temperatures makes weak parts.
@rassiasn: Make certain to set your Wipe tower extruder to one of your non-solube filaments, do not leave it at 0.
Cheerio,
RE: Trouble printing with soluble supports (PVA or Verbatim BVOH)
Unfortunately, I cannot simply print in PETG and use PLA for supports. Some of the models I have to make require soluble filament of some kind. I have several other MK3's with MMU's and print with PLA/PVA and PETG/PVA all the time with great success. So, I kinda know what I should expect from PVA.
I have had mixed results when it comes to disabling the wipe tower, but I agree with you that the wipe tower seems less essential when printing with PLA/PLA. When it comes to PVA, it seems that the nozzle really does need to be primed before moving to the actual print. I had been struggling with oozing tool loading/unloading and during printing. Since my original post, I had messed with the setting you mentioned, Retraction when tool disabled, and that really helped. I have very minimal oozing now.
I do think that lowering the temperatures isn't the way to go as you'll probably lose part strength. Again, for my printing application, that's pretty necessary. I'm still using the 0.6mm nozzles and I'm pretty sure the larger temperature is due to the larger nozzle.
RE: Trouble printing with soluble supports (PVA or Verbatim BVOH)
The issue that I'm still struggling with is reliable PVA adhesion to PLA. I expected to struggle with PLA adhering to PVA but it seems to be the other way around. My most reliable adhesion occurred at 230C. At that temperature, the PVA cracks and pops like crazy! I know that PVA can do that when exposed to moisture, so I keep all of my filament in a dry box, during and after printing. Maybe it's a print speed issue?
RE: Trouble printing with soluble supports (PVA or Verbatim BVOH)
Did you change brands of PVA or PLA since you had tried on your MMU? For me, I've found that some brands of PVA and PLA don't stick to one another no matter what I try. Sometimes changing brands of one or the other filament resolves it.
The cracking and popping sounds like your filament has absorbed too much water. Putting it in a dry box won't dry it out unfortunately. You'll need to put it in something that'll heat (like the oven on low temp) it to dry it and then in the future keep it in the dry box. I use a food dehydrator that I can set the temperature on.
RE: Trouble printing with soluble supports (PVA or Verbatim BVOH)
I've been using the Verbatim BVOH sold though the Prusa website. I've tried other brands in the past and have had the best success with the Verbatim BVOH. I haven't switched brands recently, but maybe I'll look around and see what else I can find.
I totally agree that the popping sounds is usually moisture, but I don't think that's the case here. I should have clarified that my dry box is actually a filament dehydrator in which I can set a temperature and duration. I left a reel of PVA in it overnight, where it maintained 10% humidity, and had another attempt at printing this morning. Just to make sure it wasn't a moisture issue, I manually altered the temperature during the first layer from my current testing value of 235C to 215C, and all of the popping went away. It resembled parts printed on my MK3's. However, at that temperature, I still struggle with PVA to PLA adhesion. My current test print is still going with the PVA being printed at 235C, which is definitely on the higher side, but seems to work okay. Maybe this is just want printing PVA with this printer is like?
One thing that I've thought about is switching my second tool to a 0.4mm nozzle to replicate my MK3's. I was looking at the slicer settings and it definitely seems possible, you just lose access to the wipe tower. Unfortunately, I don't have any extra XL nozzles at the moment, so I'll have to wait to get some in the mail before continuing my testing.
At the end of the day, this is all just support material, so I'm not sure how much I should actually care. Only more printing will tell for sure.
It's a while since I used it but I remember PLA to PVA adhesion required a temperature boost. PVA is so hygroscopic that it must be dried for at least 12 hours and used from a dry box then for any but tiny jobs you must protect it between the dry box and the printer - ptfe tubing or similar.
Cheerio,
RE: Trouble printing with soluble supports (PVA or Verbatim BVOH)
on the MMU I had pretty good success with bvoh, less so with PVA. What I've tried on the XL so far is Aquasys 120, and that kind of worked ok with SainsmartTPU. It got my hopes up in fact lol. the Aquasys never ever worked on the MMU due to loading/ramming/jamming issues. But I just tried prusament PETG with Verbatim BVOH and it was no good at all. I was careful to watch it since it I had no idea what I was in for. Good thing too, it basically was going to create a blob of death with the PETG. I don't have any more time to mess with it today, but I created a test object and .3mf that I'm going to try to do some refinement of. I've got the bvoh in the printdry to be sure it's not just a moisture thing. I may try again tomorrow after drying both.
RE: Trouble printing with soluble supports (PVA or Verbatim BVOH)
I'm quite surprised that PVA or BVOH isn't an option in the filament load menu, and thus you get a filament mismatch warning.
RE: Trouble printing with soluble supports (PVA or Verbatim BVOH)
so after drying both the prusament petg and the verbatim bvoh over night, still not good results. Printing at 218C the bvoh goes down fairly well with raft and interface layers. But when the prusament starts to print it never sticks and immediately starts to blob on the nozzle. it's printing at 240C. I might do this test using the aquasys 120 as a comparison.
RE: Trouble printing with soluble supports (PVA or Verbatim BVOH)
I don't want to jinx it but I'm having promising results with Aquasys 120 and petg...
RE:
I'm doing a 1h 22m print with the aquasys 120 and prusament petg.
This is the best looking I've seen so far! I'll post a picture when it's done
RE: Trouble printing with soluble supports (PVA or Verbatim BVOH)
so far so good. Print almost done
RE: Trouble printing with soluble supports (PVA or Verbatim BVOH)
Ok, I can work with this. I just made that model in blender so that line there could be a flaw in the stl. This is pretty promising. I'm doing a PLA next. Then I'm going to be adventurous and do one with tpu.
RE: Trouble printing with soluble supports (PVA or Verbatim BVOH)
PLA is good too. Next up tpu with aquasys 120 interfaces and pla supports.
RE: Trouble printing with soluble supports (PVA or Verbatim BVOH)
and tpu. Needs needs another degree or two less for stringing but the aquasys 120 worked great.
RE: Trouble printing with soluble supports (PVA or Verbatim BVOH)
Great work!
PLA is good too. Next up tpu with aquasys 120 interfaces and pla supports.
RE: Trouble printing with soluble supports (PVA or Verbatim BVOH)
I may try to use up the bvoh I have and use the aquasys as my goto since I can use it at the same bed temp as each of those materials. I'm pretty jazzed about the tpu especially since this opens up a ton more printing options with tpu that I had not considered before. Using PLA is the support and the soluble as the interface provides a much more sturdy support than using tpu for the supports.
RE: Trouble printing with soluble supports (PVA or Verbatim BVOH)
In case anyone wants to see the .3mf files for the above prints, I have attached them.
This is done with 2.7.0 final prusa slicer and latest 5.1.0 final firmware.