Nozzle Strikes on Dual Head prints

[Bvwaa 0]

Hello all, I'm 2 weeks into owning the Ultimaker 3. I've owned a 3D printer before, when it was much harder to get decent results. This thing is a dream... however, prints I attempt with dual extrusion fail miserably almost 100% of the time. If I print the same object with a single head it almost never fails. In most cases it's clear that the nozzle struck the part and pulled it free from the bed, then spaghetti. I've calibrated the Z axis 1000 times. I'm digging deeper into the many settings I feel may relate to the issue, in the mean time, thanks for your help in advance. I'm using PLA and printing these larger/longer prints on Ultra Fine

[Bvwaa 0]

Aight, so I've done my first round of trouble shooting and found a pretty awesome problem guide here, found the link searching these forums.

My very tall single print failed today about half way through. I heard the nozzle striking the support structures and then finally it struck the print and knocked it out of whack. My dual head theory... POOF. It's not pillowing, at least in the classic sense of bulbous knobby fills... I was looking at the print as it was knocking the support structure and any rise in the surface was imperceptible, or so it seemed.

I'm using all of the default settings at the moment, per template i.e. fast vs ultra fine.

My current areas of investigation based on the googles are retraction, combing, and maybe slowing lowering the temp along with the related feed/flow settings.

I've printed some really tall builds with little to no support and no problems so I feel like mayhaps I am F'ing myself by allowing ridiculous support structures to exist.

Another issue that I keep running into when running dual heads is that each head can have it's own settings... so I have on several occasions with PVA printed the support with FAST settings while the main model was on Ultrafine. I can see why that might mess things up.

[kmanstudios 1,120]

I have no solution, but I have printed the full vertical volume before on my UM3E and did not have that happen. All leveling and such is good? Do you have any pics you could show? At what height did it fail? Proper brimming or adhesion on the base of your plate? Heated bed? I know you said you were using the base pre-sets, but just trying to be thorough.

Was there any curling or other things like a blob or something to catch on the nozzle?

I will be doing a full vertical print with supports in about a week. I have a few things to catch up on regarding backlogged prints (I need another two - three printers to keep up with my design process). I will keep an eye out if anything goes awry though.

I used to have a lot of spaghetti strings all over the place when I was using the prime tower. It was prone to falling, but not the models themselves unless something curled up on an edge or got a blobby buildup. It would whack it hard enough to bounce the plate too. But I had my model really stuck down.

[Bvwaa 0]

Here are some photos.

This print was with PVA support, right at the end there was, I imagine, a nozzle strike that was pretty deep and wound up wobbling the print until the base was actually bent and it toppled. Default Ultra Fine settings with 50% fill. No idea why this failed. The base looked solid, adhesion was good.

This print was another shot at it on Normal Settings, 20% fill, PVA support. It's hard to see but the little tiny area surrounded by PVA is where the nozzle struck and the print came loose from the bed and spaghet' was made. The base looked solid and nothing looked off.

This one was another piece of the above print. I know why this one failed. Some of the brim began to peel up but I thought it was close enough to the edge not to affect it. Nope. The print moved a bit, and then some more and then spaghetti. The XY looks off but it was whole print moving. I check the XY cal before most prints.

No nozzle strike here but have a hairy print. I'm taking a sculpting class and I bought some anatomical models to print for reference. Didn't realize there was an actual skeleton in there... pretty cool looking overall but completely unintentional. This one I changed the retraction settings unknowingly while poking around trying to solve the above.

I've printed a lot of awesome stuff too. Getting ready to start some really big 5 day prints and want to make sure I know what I am doing.

Edited August 11, 2017 by Guest
Spacing and an additional blurb about successful prints!

[DF-Werkzeugservice 9]

Have you tried to print with an other profile (fast, e.g.)?

I'm only printing ABS, which of course tends to warp way more than PLA. But there I've made the experience that the warping is way worse on 0.06 layer height than at 0.2.