Every Other Print Messed Up!

[darioism 0]

Hey all, I just got my Ultimaker 2 and have been playing with some test prints. I'm still a newbie but liking it so far!

It seems though that every other print I do gets screwed up like in the image below. If I abort and immediately queue up another print of the same part, it works fine. Then the next one after that is screwed up! I don't see why. The filament is moving smoothly. Tuning settings are not changed. There is the same delay between any two prints, so I don't think cooling is a factor.

I wanted to print four tires and now have four perfectly good tires and four scraps. Any ideas? Thanks!

[gr5 2,268]

That looks very strange - I've seen hundreds of things go wrong and how they look after but this one doesn't look like any of those. Maybe if you show it after just 1 or two layers - as soon as it looks different. So please post one more picture of the bottom layer - and if that looks fine show the first bad layer.

[darioism 0]

Thanks gr5. Glad to know at least I didn't miss something basic!

Here is a shot of the bottom - best I can with the lighting I have. The print on the bottom is the problematic one. It almost looks like it's a feeder issue. But, the filament is loose and feeding fine on other prints. Maybe software related. I am on the latest firmware.

For the first layer request, I'll try to reproduce the issue and abort at the first sign of trouble the next time I run the printer.

[DidierKlein 729]

What slicer are you using? That pattern doesn't look like something the legacy Cura would do

[gr5 2,268]

Actually I think the lower print looks pretty good.

Didier I think it looks strange because he rotated it so the infill is horizontal but I'm sure it printed at an angle.

The bottom print looks properly extruded or maybe slightly underextruded. The top print looks very strange like all the plastic melted and flowed together. The line widths are much different on the top one. Leveling must have been quite different on the 2 prints maybe?

For example if you level nozzle too low (bed too high) there will be too much filament for the space to put it and if you level so that the nozzle is too high off the bed you will have air gaps like in the lower photo.

What did you set your shell width to? It MUST be a multiple of your nozzle - so usually 0.8mm. If not you get things like the upper photo - but on every layer - not just the bottom layer.

[SandervG 1,521]

Hi Darioism,

Are you printing them together, or just one at the time?

How big are these prints?

The prints look kinda marble-like. Is that intended or is it suppose to be smooth?

Have you tried different reels of filament?

Could you be bothered uploading a picture of your printhead as well?

Sorry for all the questions

Thank you!

[gr5 2,268]

Maybe a 10 second video or so would help.

Usually we see underextrusion due to extruder or Z movement issues and you see lots of stringy stuff. Maybe you removed that? It looks like you made an underextruded print and then melted it afterwards. I've never seen anything like this. Maybe it's just a bad photo?

Is your bed at 60C? It looks like maybe your bed is at 100C.

[gr5 2,268]

Maybe the MOSFET that controls your heated bed gets stuck on and the bed reaches 100C? You could check bed temp with an IR temp sensor. Or just touch it. I can hold my finger on 60C glass for 10 seconds no problem. 100C - only maybe 1 second.

[darioism 0]

Thanks for all the replies! I'll try to answer what I can. And thanks for your patience, as I am a newbie but SO motivated to do great things with this.

DidierKlein - I'm using Cura 15.04.2, which it tells me is the latest. The print was set to "Ulti" quality.

gr5 - Your explanation makes perfect sense, but I didn't change the leveling between those prints. They were sequential - the bed didn't even cool off much. Then the print right after the successful one failed. I'm using the quick print settings in Cura, but when I change to expert the shell width is 0.8. I have an IR thermometer and the bed is 62.3 degrees C while doing a print right now (did not test when the problem happened but I'll keep that in mind).

SandervG - Those prints were not printed together, but they were sequential. The prints are pretty small - only about 15mm across. I'm wondering if this is related. Since I'm still learning, I wanted some small quick prints to use for practice. Maybe the material didn't get a chance to cool enough when the head came back around for another pass, so it doughed up. As far as the marbling, the prints are supposed to be smooth Jeep tires. I have not tried different reels yet, I'm still using the one that came with the printer.

As far as the photo of the bottom, what you're seeing is what I'm seeing. The two prints are lined up the same, so it's not an artifact of the angle or lighting. I made sure to set up a light so I can represent the issue as best as possible. Agreed that the best level of extrusion is probably somewhere in between those two - but neither are too bad. It's the top that went all screwy. I added another photo below with as little angle as I could. (Left is the good one, right is the screwy one.)

Today, everything seems to be working fine. (As always happens after posting a problem to a message board.) But, I'll take video if I can and more photos next time it happens.

So, still not solved but not happening today, and I have a few things I can check next time it happens.

Thanks!!

[skinny-kid 65]

Can I ask what filament you are using? Have you tried printing them both together rather than sequentually?

I ran into a problem with Ultimaker silver filament when I first started 3D printing. If I didin't let the head cool all the way down and tried to run a print before then, the second print would not print correctly since the nozzle had a clog. I would have to atomic pull and make sure all was clean before running again.

If I waited until the head and the bed had cooled, then I didn't have this issue.

It may be what you are dealing with. The problem for me stopped when I switched to Colorfabb and Faberdashery filaments.

[darioism 0]

Thanks for your help everyone. So far the problem has not reoccurred. (My printer was probably watching this thread and felt threatened.)

skinny-kid: I was using the Ultimaker PLA Silver that came with the Ultimaker 2. Yes, it may have been a simple clog. Maybe it cleared on its own. Will try an atomic pull next time. At the moment I've switched out to ABS of another color and it's working fine. (Well, bed adhesion is a problem, but that's another topic altogether!)

I will have to look into those other filaments. (They're all so expensive!) As I understand it, anything other than "Ultimaker" filament will take some tweaking to get right.

Anyway, I guess this topic can be closed for now. Hopefully this thread will give other newbies some direction. Thanks!!

[gr5 2,268]

All PLA print about the same and are equally easy to get working. Learning a new material like nylon, pet, or ABS takes a while - maybe 100 prints - before you are getting perfect prints every time.

I mean you might get something that is okay first try but e.g. with ABS you might have very weak parts with bad layer adhesion that seem fine until you break it and realize how damn weak it is. or it might string like crazy or every 4th print might pop off the bed or you might get nozzle clogs on every other print. PLA is the easiest and once you learn *any* material it is painful to switch.