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just got my MMU2 MK3 up and going.  

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JuanCholo
(@juancholo)
Honorable Member
Topic starter answered:
Re: just got my MMU2 MK3 up and going.

I've been tweaking mine to see if i can improve the mk3 printer itself which i'm unhappy with.

well took longer to print the new parts then it did to install them. my mmu2 is back up again.

“One does not simply use a picture as signature on Prusa forums”

Posted : 27/11/2018 1:44 pm
JuanCholo
(@juancholo)
Honorable Member
Topic starter answered:
Re: just got my MMU2 MK3 up and going.

trying BVOH for the first time today cross fingers.

“One does not simply use a picture as signature on Prusa forums”

Posted : 11/12/2018 2:19 am
toaf
 toaf
(@toaf)
Noble Member
Re: just got my MMU2 MK3 up and going.

I'm gona try the pva when my next print is done. I have the perfect "guest filament" holders.

I am gonna try full pva no interface yet. me and supports don't get alone well.

I have a Prusa,therefore I research.

Posted : 11/12/2018 3:05 am
JuanCholo
(@juancholo)
Honorable Member
Topic starter answered:
Re: just got my MMU2 MK3 up and going.

so i'm really not impressed with BVOH at all.

my test print completed 100% no problem. but what i was expecting BVOH to be did not come true.

1) it is basically dried Elmers glue in a filament form
2) it barely sticks to itself
3) it contaminates the nozzle and effects the PLA next in line to be extruded, makes the PLA brittle and does not stick well to the layer below.
4) does't exactly dissolve without massive agitation of the material
5) causes layer bonding weakness in the Wipe Tower, possible wipe tower failure on some prints.

i would not trust a BVOH supported part to be as structurally strong using traditional support methods, the output might look nicer for overhangs but it will break easily.

here was a thread on PVA verse BVOH
https://shop.prusa3d.com/forum/others-archive--f51/pva-vs-bvoh-t12561.html

i can see others have the same issues:

"It’s nice to see your succes with BVOH. I have done some really excellent prints using 4 PLA colors but when I use my BVOH the parts come out really brittle and separate really easily. I’m not sure if the BVOH is hanging around in the nozzle or what. I’m not sure what to try. I bought the multimaterial mod mainly for soluble supports but have not had good luck. Would you mind sharing your gcode? Perhaps I could give it a try. I am also using verbatim BVOH I bought, its from amazon though so maybe it’s old or something. Was sealed really well."

“One does not simply use a picture as signature on Prusa forums”

Posted : 11/12/2018 4:50 pm
Flaviu
(@flaviu)
Estimable Member
Re: just got my MMU2 MK3 up and going.


so i'm really not impressed with BVOH at all.

my test print completed 100% no problem. but what i was expecting BVOH to be did not come true.

1) it is basically dried Elmers glue in a filament form
2) it barely sticks to itself
3) it contaminates the nozzle and effects the PLA next in line to be extruded, makes the PLA brittle and does not stick well to the layer below.
4) does't exactly dissolve without massive agitation of the material
5) causes layer bonding weakness in the Wipe Tower, possible wipe tower failure on some prints.

i would not trust a BVOH supported part to be as structurally strong using traditional support methods, the output might look nicer for overhangs but it will break easily.

here was a thread on PVA verse BVOH
https://shop.prusa3d.com/forum/others-archive--f51/pva-vs-bvoh-t12561.html

i can see others have the same issues:

"It’s nice to see your succes with BVOH. I have done some really excellent prints using 4 PLA colors but when I use my BVOH the parts come out really brittle and separate really easily. I’m not sure if the BVOH is hanging around in the nozzle or what. I’m not sure what to try. I bought the multimaterial mod mainly for soluble supports but have not had good luck. Would you mind sharing your gcode? Perhaps I could give it a try. I am also using verbatim BVOH I bought, its from amazon though so maybe it’s old or something. Was sealed really well."

If the print quality of BVOH is getting worse you have to dry it at about 50°C for several hours. And you have to print it on higher temperature. I am printing it at 210 °C and it works great. It sticks better to the bed if you use glue stick.
Of corse you have to print it out of an humidity controlled box. You have to increase the purging on bvoh a lot. If you have problems with dissolving it increase temperature of water. It dissolves A LOT faster than pva.

Posted : 12/12/2018 9:24 am
JuanCholo
(@juancholo)
Honorable Member
Topic starter answered:
Re: just got my MMU2 MK3 up and going.



so i'm really not impressed with BVOH at all.

my test print completed 100% no problem. but what i was expecting BVOH to be did not come true.

1) it is basically dried Elmers glue in a filament form
2) it barely sticks to itself
3) it contaminates the nozzle and effects the PLA next in line to be extruded, makes the PLA brittle and does not stick well to the layer below.
4) does't exactly dissolve without massive agitation of the material
5) causes layer bonding weakness in the Wipe Tower, possible wipe tower failure on some prints.

i would not trust a BVOH supported part to be as structurally strong using traditional support methods, the output might look nicer for overhangs but it will break easily.

here was a thread on PVA verse BVOH
https://shop.prusa3d.com/forum/others-archive--f51/pva-vs-bvoh-t12561.html

i can see others have the same issues:

"It’s nice to see your succes with BVOH. I have done some really excellent prints using 4 PLA colors but when I use my BVOH the parts come out really brittle and separate really easily. I’m not sure if the BVOH is hanging around in the nozzle or what. I’m not sure what to try. I bought the multimaterial mod mainly for soluble supports but have not had good luck. Would you mind sharing your gcode? Perhaps I could give it a try. I am also using verbatim BVOH I bought, its from amazon though so maybe it’s old or something. Was sealed really well."

If the print quality of BVOH is getting worse you have to dry it at about 50°C for several hours. And you have to print it on higher temperature. I am printing it at 210 °C and it works great. It sticks better to the bed if you use glue stick.
Of corse you have to print it out of an humidity controlled box. You have to increase the purging on bvoh a lot. If you have problems with dissolving it increase temperature of water. It dissolves A LOT faster than pva.

what are your speed settings?

i dried my filament for 12 hours and on the first test with more Purge i found the BOVH was not sticking and then causing spaghetti.
i then noticed the Prusa BVOH settings have the infill set to 50mm/s where the website for Verb says to run at 30mm/s
so i lowered the Support speeds down by 10 and increased the temps from 195 to 205 it was a little better but i'm wondering what your settings are.

“One does not simply use a picture as signature on Prusa forums”

Posted : 14/12/2018 5:59 pm
Flaviu
(@flaviu)
Estimable Member
Re: just got my MMU2 MK3 up and going.

Settings for Verbatim BVOH. When using full soluble support I need glue stick on the PEI bed.

Posted : 14/12/2018 6:31 pm
Flaviu
(@flaviu)
Estimable Member
Re: just got my MMU2 MK3 up and going.

And ramming ...

Posted : 14/12/2018 6:31 pm
JuanCholo
(@juancholo)
Honorable Member
Topic starter answered:
Re: just got my MMU2 MK3 up and going.

ok so your support speeds are about half where i am now, so i will cut back and try again.

“One does not simply use a picture as signature on Prusa forums”

Posted : 14/12/2018 9:19 pm
AbeFM
(@abefm)
Member
Re: just got my MMU2 MK3 up and going.


so i'm really not impressed with BVOH at all.

my test print completed 100% no problem. but what i was expecting BVOH to be did not come true.

1) it is basically dried Elmers glue in a filament form
2) it barely sticks to itself
3) it contaminates the nozzle and effects the PLA next in line to be extruded, makes the PLA brittle and does not stick well to the layer below.
4) does't exactly dissolve without massive agitation of the material
5) causes layer bonding weakness in the Wipe Tower, possible wipe tower failure on some prints.

i would not trust a BVOH supported part to be as structurally strong using traditional support methods, the output might look nicer for overhangs but it will break easily.

here was a thread on PVA verse BVOH
https://shop.prusa3d.com/forum/others-archive--f51/pva-vs-bvoh-t12561.html

i can see others have the same issues:

"It’s nice to see your succes with BVOH. I have done some really excellent prints using 4 PLA colors but when I use my BVOH the parts come out really brittle and separate really easily. I’m not sure if the BVOH is hanging around in the nozzle or what. I’m not sure what to try. I bought the multimaterial mod mainly for soluble supports but have not had good luck. Would you mind sharing your gcode? Perhaps I could give it a try. I am also using verbatim BVOH I bought, its from amazon though so maybe it’s old or something. Was sealed really well."

I haven't tried PVA in my Prusa yet, though I've used up several spools on a dual nozzle system.

What I *HAVE* found on the Prusa was when printing in multi material (TPU/PLA or TPU/PETg) is that more purge helps layer bonding significantly. After one perfect squeegee I turned down purge volumes to where it looked fine, but my TPU blade kept splitting. Turning up the purge fixed this.

And yeah, the more you dry the PVA the better. I keep it under desiccant, I think it helps, but baking it before use is almost always noticeable, and I will bake it if it's been sitting for a few weeks, even properly stored. Using eSun.

I maintain an informal list of San Diego, CA 3D printing enthusiasts. PM me for details. If you include a contact email and I can add you to the informal mailing list.

Posted : 17/12/2018 7:07 pm
JuanCholo
(@juancholo)
Honorable Member
Topic starter answered:
Re: just got my MMU2 MK3 up and going.

after using the BVOH for a bit now i'm not really impressed with it.

my filament must be pretty dry since baking it for 18 hours had no measurable improvement. It did make it stringyer , either that or as i get to the center of the spool the material has changed in composition.

no mater the temperature range from 190 to 220 the material will barely bond with itself, now this could be more the slic3r then the material. but...

besides that it takes forever to dissolve, you need a lot of manual clean up to get the stuff out of the nooks and crannies. a lot of it does not dissolve and you get this thick snot that you have to sit there and manually remove. you are better off trying to design away from overhangs and not using a material like this.

no matter the purge there is still a weakness introduced into the model when using BVOH. i increased my purge to 200 there was still some cross contamination visible.

the stuff is very much like elmers glue that has been dried and turned into filament i expected something more like a starch that would complete dissolve in warm water.

i've had it jam a few times because it has been pretty stringy no matter my settings. you factor in the cost for the stuff and it is even more worthless.

some of my BVOH tests
ball in a cage

pallete gear test

“One does not simply use a picture as signature on Prusa forums”

Posted : 17/12/2018 8:01 pm
JuanCholo
(@juancholo)
Honorable Member
Topic starter answered:
Re: just got my MMU2 MK3 up and going.

after a few more prints using soluble filament i can confirm i HATE the stuff.
after lots of testing all i found was it still caused cross contamination and weak spots in prints where it was used. no matter how large i set the purge there would still be some bleed of the soluble into the PLA i was using.

for example a few weeks after printing that yellow gear pallet test i accidentally dropped it on the floor and it shattered right on the 2 main soluble plains that the print used to support the gears during a one piece print.

I setup a 90 degree overhang test between soluble and standard supports and hands down the standard supports produced a stronger part while the soluble version fractured right right where the soluble material would contaminate the PLA.

in short, the use of soluble produces a pretty print with a easier clean up however it is mechanically flawed and will not stand up to the same loads as a version were traditional supports are used with harder clean up.

i would only use soluble in a mechanical sense when creating a pretty part that would then be Mold and cast from a resin, which defeats the point of 3d printing the part in the first place.

it really is amazing how a very small amount of contamination from the soluble into the pla can dramatically weaken the structure.

factor in the cost of BOVH and it makes you want to stay away from it further.

at any rate the promise of PVA or BOVH for me is a no go and it was one reason i wanted the MMU as i was taking extra time to design special break away supports in creating mechanical parts and i though a soluble solution would speed things up.

“One does not simply use a picture as signature on Prusa forums”

Posted : 03/01/2019 4:37 pm
Flaviu
(@flaviu)
Estimable Member
Re: just got my MMU2 MK3 up and going.



however it is mechanically flawed and will not stand up to the same loads as a version were traditional supports are used with harder clean up.

Your purge volumes are not big enough so you mixed BVOH into your PLA.

Posted : 03/01/2019 7:56 pm
JuanCholo
(@juancholo)
Honorable Member
Topic starter answered:
Re: just got my MMU2 MK3 up and going.




however it is mechanically flawed and will not stand up to the same loads as a version were traditional supports are used with harder clean up.

Your purge volumes are not big enough so you mixed BVOH into your PLA.

sure lets waste 1/4 roll of PLA getting all the BVOH squirted out for a print with 400 tool changes. no thanks.

“One does not simply use a picture as signature on Prusa forums”

Posted : 03/01/2019 11:39 pm
JuanCholo
(@juancholo)
Honorable Member
Topic starter answered:
Re: just got my MMU2 MK3 up and going.

it should be noted i do not fault the MMU for issues with soluble material.

the failure is in the material itself not the machine.

“One does not simply use a picture as signature on Prusa forums”

Posted : 04/01/2019 5:28 pm
Scott
(@scott-9)
Member
Re: just got my MMU2 MK3 up and going.

Just a general question. What size is the steel ball?

Posted : 06/01/2019 6:37 pm
JuanCholo
(@juancholo)
Honorable Member
Topic starter answered:
Re: just got my MMU2 MK3 up and going.

i've been very sick and have not touched my mmu2 in about a month. the last thing i did was upgrade to the latest firmware and never even had a chance to test it.

“One does not simply use a picture as signature on Prusa forums”

Posted : 25/01/2019 9:18 pm
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