IRobertI

She said "core", can only be UM3. Take the core out and check the connections both on the core and inside the head, do they look clean and undamaged? Take a look at the small wires on the back. Tug on them lightly and see that they are attached to the PCB.

What I thought ultiarjan was referring to is that the support (in your first picture) is wrapping around to the backside of the pillar which seems to be more than it should be doing just because of the horizontal expansion. I thought the option to connect support structures to make them stronger was causing it. So I took a model with a similar shape to yours and played around with the horizontal expansion and that second option, but it didn't seem to be making any difference. At least not for that particular model.

I suspected that as well and did some testing on it last night. But it doesn't seem to be the case. Unless I did something wrong while I was messing around with the settings.

It could be "Support horizontal expansion" causing this. By default the value is fairly high (and can help make better prints), try lowering it and see if the extra support goes away.

Careful during the install though. I noticed today that 2.6.1 tries to install in the 2.6 directory by default so I had to add the ".1" manually.

One disadvantage with having flats on the shaft is that it becomes a lot more critical to do it right during assembly. If you tighten the screw and the flat isn't perpendicular to the screw, the shaft can then rotate ever so slightly and all of a sudden the screw isn't gripping at all any more. I'd say the problem has been lessened a lot. In the beginning it was quite common to have shafts that could shift back and forth after shipping (I tested literally hundreds of UM2s a couple years back). These days it doesn't appear to happen as much. Probably a combination of different packaging, better quality control and torque drivers to set the screws properly.

I'm gonna sound like a real ass here but... Why don't you just make one? As an owner of a 3d printer you should learn some basic CAD. It'll open up your world to a lot of possibilities beyond printing trinkets from Thingiverse.

You don't need to change any settings to move the part below the build plate. The setting I'm guessing gr5 is referring to is "Automatically drop models to the build plate" which makes sure that the model gets pushed down to the build plate in case you drag the model upwards. I'm guessing this is an issue with your model rather than cura. But moving it down slightly as suggested will probably take care of it (if it's ok that the model becomes ever so slightly shorter).

Is the fan on the back of the print head running? It should either run as soon as you turn the printer on, or after the nozzle has reached about 40C. What did the atomics look like? Could you see the internal shape of the nozzle, all the way to the tip? After two years, the PTFE is probably toast like others have already said, so I would replace that one regardless. But I would suggest that you buy the TFM and spacer used for the UM2+ instead as these hold up a lot better (or just go for the UM2+ upgrade kit, it's well worth the money IMHO).

What does it look like in xray view? Any red areas there if you spin the model around? Regardless of you seeing any red or not I would run the model through an STL repair service and see if that takes care of the problem.

On large prints your head stays close to the hot bed for a longer time which makes the issue worse, that's why you're seeing it more on large prints. I'm sure it will be solved with a new/fixed fan. Make sure the fan is actually broken and that it's not just a wire that is pushing into the blades (or a stray piece of plastic).

Could be a backlash issue. Check the short belts on the stepper motors. Make sure they're fairly tight. An easy test for this is to print 2-3 concentric rings and see if they are truly round or not. See the image to the left here: http://support.3dverkstan.se/article/23-a-visual-ultimaker-troubleshooting-guide#circles

"Fix horrible" has been renamed. Those fixes are now under "Mesh fixes" which you can add into your collection of settings by going to Settings -> Configure settings visibilty. Scroll down to "Mesh fixes" and tick all the boxes for that heading. Then you can experiment with different combos. Also try running it through a stl repair service like: https://service.netfabb.com/login.php Or similar services (Microsoft's 3D Builder app has such a feature as well. A surprisingly good app btw).

Also check that it isn't something really silly like a piece of plastic somewhere that is rubbing up against something. If you turn off the printer and move the bed up and down manually by grabbing the bed towards the back and pulling it up and pushing it back down, does it move smoothly? If you can't get the bed moving from the bottom you might need to use your fingers to twist the z-screw to get it up a couple of cm, after that you can usually pull it up manually.

Have you tried starting it up without any of the possibly damaged cores installed? If it starts up without cores installed you've found your problem. Check the board inside the head, does it look damaged? If you manage to get it started without the cores, do a firmware update. An update that was just pushed out deals with a few bugs that have to do with communication issues. If none of that helps, get in contact with your reseller. They'll have routines in place to deal with a flooded head. You might need to replace the entire head.

HT is what I used to get my results. You need heat, slow speed, thin layers and preferably a bigger nozzle (0.8 nozzles just came out for the UM3 so that's sorted). One issue with the thin layers and high temp is that you get buildup of material on the nozzle. It then burns and starts flaking off into the print leaving brown marks all over. I was using an UM2+ at the time and designed a little arm that holds a wire brush. I then created a plugin that makes the head move over to the brush and clean it off every few layers. And then after all that you need to polish the crap out of the print. Wet sandpaper followed by a polishing wheel with polishing paste is what I used. I posted one of my prints at the link below. I made a few more prints after that where I improved the result slightly but I never bothered taking any pics of that. https://ultimaker.com/en/community/prints/508-ht-clear-experiment I also gave nGen a try but didn't have much luck with it. It got cloudy quite quickly as soon as the print got up to a height where the heat from the bed wasn't contributing as much.

The only clog I've cleaned on an UM3 was a fair bit smaller than that (cleaned a few massive clogs on UM2s though), but what I used then was a heat gun. The type you use to strip paint, but on the lowest setting, obviously. It's quite tricky on the UM3 since it's a lot harder to take parts away from the head and it's mostly plastic. If you want to give it a go, try heating the core(s) normally first and see if you are able to free them that way, doubtful. If not, use a heat gun (or a powerful hairdryer like gr5 said, if it's something like PLA that goes soft easily) and _carefully_ heat just the core and the blob of plastic around it. I would probably use some tinfoil to shield the plastic parts and fans of the head as it's quite easy to overheat them. Try concentrating on getting the plastic between the black part of the core and the core soft first and see if you are able to release the core. If not, try heating more of the surrounding plastic to get it to let go of the head. Don't pull too hard on the plastic blob once it gets soft, it's VERY easy to pull the wires out of the core and then you loose the ability to heat it easily in place. Or, what I would recommend more in this particular case, get in contact with the place you bought it from. They'll be able to help you out with this.

We don't have an official-official number on it, but 0.3-0.5nm will work well. Do _not_ go over 1nm with the Ruby as that may damage it.

And you're sure they're not already in the pulleys?

If your workplace had competent IT people they would know that 4 positives on Virustotal doesn't really mean anything.

Uploaded a zip with step-files. Hope it helps. https://www.youmagine.com/designs/alternative-um2-feeder-version-two

Yes, he does get a notification It's OK with me. I really should put the steps up on the site. I'll see if I can remember to do that tomorrow.

I've printed with it together with PVA and it worked fine. However, the shape I was supporting was quite basic, a dome shape, so YMMV. I'm sure it will be added eventually but the nature of the UM3 "eco system" means a ton of testing goes into a material before it gets officially added.

Load the model you want to print Load another model which you will use to define where you want extra support. Position the second model (you may have to disable "Keep objects apart" in Cura's options). Select the second model and then click on the "Per object settings" button on the left. Add in the Support Mesh option and any other options you want to modify. Hopefully that makes sense.

Yeah I noticed that as well. I looked at the resulting gcode in Repetier Host as well to rule out any bugs in the layer view of cura (spiralize is/was notorious for not showing up correctly) but it's missing there as well. So yeah, something is borked there.