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PVA for support problems

Posted: Tue Oct 03, 2017 7:49 pm
by Explorer74
I'm trying to use PVA for support on a MakerGear M3 Independent Dual. I have a prime pillar and ooze shield. The problem I'm having is that the PVA is not very strong and part way through the print the prime pillar break off at one of the PVA layers and the extruders start spitting plastic all over the build table. I have tried making the prime pillar bigger and that seems to help a little, meaning it takes longer to break off. Does anyone have ANY ideas on how to fix this problem .. or work around it? I love the partial prints I get with the PVA support and dense support from Simplify3D. Just wish I could get all the way through a print.

Re: PVA for support problems

Posted: Wed Oct 04, 2017 12:27 am
by Spotopolis
Sometimes no matter carefully you have z height and level dialed in, if there is any ooze, little blobs can form on the extruder head and cause it to hit delicate support structures and knock them over or off the bed.

Have you tried adding any "Retraction Vertical Lift" under the extruder/ooze control panel in S3D? 0.20mm is usually enough to solve the issue for me, and I only use it when the supports are thin and spindly since it does add a bit of time to overall print. That said, that small additional time is usually much preferable to having a print going for hours and then failing.

Re: PVA for support problems

Posted: Wed Oct 04, 2017 5:50 pm
by Explorer74
Actually, I have a 1mm retraction verticle lift. Probably too much. I also contacted Simplify3D. They had some good suggestions. First, use PLA for the supports and only use PVA for the dense support just before it contacts the model. Second, don't use a prime pillar. Add a couple more layers to the ooze shield and let it act as the prime. Getting ready to try it now. I'll let everyone know how it works.

Re: PVA for support problems

Posted: Sat Oct 07, 2017 10:06 pm
by Explorer74
Okay, status report :-) I think I finally have this working. I have done away with the prime pillar and using 3 outlines for the ooze shield. That was still giving problems because the PVA was oozing out of extruder what it waited for all the PLA to print. I again contacted Simplify3D and then gave me a simple script to turn off the PVA extruder when it isn't being used. The tool change script now turns the temp down to 165 C when the printer changes to the T0 tool .. and then back up to print temp when it changes to the T1 tool. This takes a little longer, but works quite well. I am including the Tool Change script I am using with my M3ID.

{IF NEWTOOL=0}G1 X250 F18000 ; park T1
{IF NEWTOOL=0}M104 S165 T1; set T1 inactive extruder to 165 C
{IF NEWTOOL=0}G1 X-25 F18000; maker sure t0 is parked

{IF NEWTOOL=1}G1 X-25 F18000; maker sure t0 is parked
{IF NEWTOOL=1}M109 S[extruder1_temperature] T1; Heat T1 to T1 Temperature
{IF NEWTOOL=1}G1 X250 F18000 ; park T1

I may try going a little lower for the T1 setting. Maybe 160 or 150 C. There should be a good balance between time to heat (about 24 seconds now) and oozing. I have noticed the most of the oozing I am getting is while the hot end is either cooling down or coming back up to temp, so I don't expect the bottom temp to have much affect.

Re: PVA for support problems

Posted: Sat Nov 11, 2017 8:27 pm
by mathisyourfriend
My problem has been the PVA breaks off in the T1 hot end after 2-5 hours (3 times so far). I've printed at 215 and 210 C. Is this too high? What else could cause this? I used T1 with PLA and Polysupport with no problem. I also use cleaning filament whenever I change filaments.
ESun PVA btw. I've had good luck with some of their other products