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?? Are you saying cura 15.04.5 doesn't run on windows? I've used it for years on windows but it might not work on windows 10 I suppose. It's from 2015. (the 15.04 in the version is the year and month it was released). I'm pretty sure cura 15.X runs on windows 7 - I'm 90% sure I had windows 7 on my computer that died last year and 90% sure I ran cura 15.X on it.

What you see in the above picture is (mostly) desirable. If it's overextruding then you have excellent "squish" into the print bed and your part will stick better. It may look "ugly" now but soon the next layer up will cover that up. However you can still make it look better if you really want. Are you printing on blue tape? Are you washing the blue tape with alcohol (blue tape has a waxy surface that parts don't stick to well but 5 seconds with isopropyl alcohol fixes that)? The Ultimaker printers don't need blue tape - you can print directly on the glass.

Yes! This. When exporting to STL it's tempting to do high resolution (more detail, more triangles) but this can cause problems for Marlin which doesn't have much memory and can only plan 16 moves ahead. Also Cura will throw away some points/gcodes if you have too many - this is adjustable in cura. See these 3 settings in cura and read their descriptions: Maximum Resolution Maximum Travel Resolution Maximum Deviation

If you email ultimaker they will send you the UM3 marlin source code. I tried it. They sent it to me. I can send to you if you want. I forget where I put it but I'm sure I labelled it and placed it carefully such that I could find it again. I just found it. It's from 2017 but I'm 98% sure they didn't touch the path planner. They have never touched the path planner so it's the same as regular Marlin from many years before 2017. The sort of things they change are gcodes and features like reading sensors and stuff like that. Not the path planner. Send me your email in a DM and I'll email you the code. Anyway I've been over the source code of Marlin's path planner like 10 times and know it (knew it) pretty well. Are you familiar with it? If not I'll tell you a few details: Ultimaker Marlin looks 16 moves ahead. The path planner doesn't know what's in the 17th move and it may need to come to a complete stop so it never reaches a speed such that the 16th move can't come to a complete stop. In other words at any given moment there are typically 16 moves in the queue that have been planned and if you look at them they tend to be a general deceleration to a stop on the 16th move (if they are all short moves). If there is a "long" move (over 16mm long) then you can go max speed up to that move which alone will be able to come to a stop if necessary. These 16 moves in the queue keep getting updated when move is completed and a new move is ready to be added (each gcode is one move). They are updated to higher print speeds. So here is one cause of slowing/stuttering/erratic moves: If you have say 50 moves very close together like on a corner with way too many triangles, then the printer has to come to almost a complete stop and prints that corner very slowly. If you are printing artwork such as "yoda" and there are lots of movements in different directions on an irregular bumpy surface and there are too many triangles you also get stuttering, erratic printing. Usually this can be fixed with triangle decimation which reduces the triangles in an STL without changing the part's overall shape much at all.

@CarloK - thanks for this info! This is valuable for me to know to be able to help people and this is the first I heard of it. In the future I can tell them to update their firmware.

You could install an old version of Cura such as version 15.04.5: https://github.com/Ultimaker/Cura/tags?after=lulzbot-17.11 That version should use much less memory and was a very solid version with I think zero bugs. It has fewer features but it creates excellent prints.

It slices just fine for me also. So your model is fine. I would try rebooting the computer where it wasn't slicing. If that doesn't work I'd try TOTAL remove of Cura which is not easy to do. You have to remove all "user" files. Which is different for different operating systems.

Oh! yes. Go to the normal download page for cura: https://ultimaker.com/software/ultimaker-cura Then just below the huge download button click on the "previous" versions link. There's only one version with "alpha" in the title.

pva/pla work pretty well together. PVA just isn't as easy to print as most materials but it does the job.

@dirrunner please post your project file: go to menu "file" "save...". The resulting file contains not only your STL but the scaling, positioning. Also it has your machine (printer) settings, your material settings, your profile used, and settings that you overrode. Please post that here.

Y=-20 means 20mm left of center of your printer. however... For some reason, Cura thinks you have a delta printer. But I'm sure you don't. Go to left side of screen in PREPARE mode. Click on your printer, then do "manage printers" then "machine settings", Uncheck "origin at center". That will fix it so it prints in the center of your printer instead of the front left corner.

I would avoid using this printer for more than a 1 hour print until you resolder the sensor wires to the bed. Yes it's good to dry out PVA. It's fine when right out of the package. It can absorb water in just a day or two and be "bad". The symptom is you can hear it popping and sizzling and see steam coming out as you print the PVA. PVA is just harder to print. I don't think it works at all with ABS by the way. https://support.ultimaker.com/hc/en-us/articles/360011461000-Ultimaker-3-Material-compatibility Yeah in the link above ABS doesn't work great with PVA. To print ABS well you need the bed at 110C. But that's probably so hot that the PVA will melt on the bed. Breakaway works great with ABS. I recommend never using ABS anyway. Ever. It's nasty stuff and any properties you may need you should be able to find elsewhere. It's difficult to print and smells nasty. Back to PVA. Put 10cm of PVA filament on the heat bed and a towel over that and heat to various temperatures. I forget now but I think PVA gets quite soft around 70C or 80C (like clay). After sitting at temp for 15 seconds, pull out the pva and bend it and if it goes back to the old shape then that temp is fine but if it moves to the new shape then that's probably too hot for drying PVA. So I forget the ideal temp but assume it's 70C - put the whole spool on the bed with a towel over everything and a few blankets on that - leave it overnight to let all the water escape. If you are doing a quick print and only need a meter then just unspool a meter and put it on the bed under the rest of the spool. Again, cover with towel and let it dry for 30-60 minutes. Never leave pva on the back of the printer overnight unless it is being used for a print. When not in use store in zip lock bag with LARGE pack(s) of dessicant. Recharge dessicant every few months.

Realize that when you next upgrade Cura you will have to edit that file again.

I watched the video. It looks like it leveled everywhere. I see some areas that have purple glue stick. I'm wondering if maybe the bad leveling happened on either side of a glue stick blob? If the nozzle hits something (some leftover brim or something) and then the part is right next to that bump the leveling might print too high in the area of the bump. I would take the glass out. Clean it very well with soap and warm water. Then do a final cleaning with glass cleaner. Then in stall glass back into printer. Then put on some of that purple glue stick. Then wet a tissue and spread the purple glue stick all over and thin it out (and in the process remove most of it). You want the glue so thin you almost can't see it. Then heat the bed to 60C until all the water dries and you are left with an almost invisible layer of glue (AND NO HAND PRINTS). Then try printing again. That's all I got but I think somehow active leveling failed you.

Could it be related to some clips or things on your print bed? There's a ".def.json" file that describes your printer somewhere. The nicer json files have more information in them including intricate details or your print bed. The file should be in a folder called "definitions". somewhere. Files look something like "anycubic_i3_mega.def.json" (example that will be in that folder).

So look at all the "horizontal expansion" parameters (search for them in the settings search box). If you have any kind of support turned on then that could be the problem. Do you have support enabled? Your part doesn't seem to need it so turn it off. There is "initial horizontal expansion" and regular "horizontal expansion".

set "travel avoid distance" to zero. disable brim and skirt both! details here: https://support.ultimaker.com/hc/en-us/articles/360013799339-How-to-print-the-maximum-build-volume-in-Ultimaker-Cura

I think the problem has more to do with the rear area of your print bed. The glass is tempered which results in a glass that is not perfectly flat. You get a very wide piece of glass (at least a meter) where the center is thicker and the edges are thinner. I think Ultimaker probably gets the center cuts only. But even so the glass is not equally thick everywhere and tends to be higher in the very center (like a mountain) and lower all around the 4 sides. BUT WAIT - you have an S5? It looks like an S5 which does active leveling. I think I know what the problem is! Active leveling only probes in the area where the print is plus around the print a bit. I suspect there is a bug with "one at a time" where it only probes in the general area of where the first print is. Do this: Do your "one at a time" print and watch the printer do active leveling. Make take a video. My guess is it will only probe a few points (say 16 or so) around where the FIRST print is to appear and won't bother leveling the rest of the bed. You might be able to fix things by doing a manual level and doing a really good job of it. Maybe. But the glass might not be flat enough. If I'm right and this is a new bug I want to let the firmware people know.

@CarloK - this is fascinating - are you sure "line error" can ever possibly refer to active leveling? I've seen other people get this error for example if they pull out the usb flash drive during printing and thought it only ever implied a corrupt gcode file (somehow). But if this error can occur during leveling that would be useful for me to keep in mind!

I think something is wrong with your printer that you have to print so slow (well 30mm/sec is not so bad - that's typical of my printing speeds but I've also printed at 70mm/sec and faster). I mean you can just keep printing like this but I think your feeder might be relatively weak (compared to most Ender 3 printers). Maybe there is something on the feeder to tighten? Or some other issue. EDIT - I forgot this wasn't PLA. I print a lot of PETG but not enough to feel confident what speeds are normal. It may be you need to print a little hotter (which makes the filament less viscous). 30mm/sec might be the best you can do for PETG - I really don't know.

And send me a direct message - it took me 3 days to notice you replied (sorry!).

That 3mf file is corrupt. Cura wouldn't open it. I renamed it to test.zip and unzip said it was corrupt (3mf files are actually zip files). Could you try again? In cura get the problem to happen then do "file" "save..." and post that file.

Yes! The fan as robinmdh said. If the front fan (not the side to fans - the fan in the print head) stops spinning then that's the problem. You can manually heat one or both cores and as it passes around 40C or so the fan should start up. The newer cores might be faulty. I kind of doubt it but it should be a strong possibility. Try an old core if possible. I didn't ask the first time but - how did you get the filament out if you couldn't get the filament out?

Let us know what happens!

Let us know what you learn!