gr5

It should take less than 1/2 second to do the retract. The gcode looks fine to me. There is nothing in the gcode to move the Z up (or bed down) but there shouldn't need to be. Adding a G28 Z might be best as that homes the Z axis which for the UM2 is when the bed is all the way down. Maybe followed by: G28 X Y Which homes the x and y axes. But you shouldn't need to do that. The firmware should do that automatically at the end of the print.

By the way, I know this is the problem because your filament on the left is filling that space inside the metal cylinder you circled. Which you are clearly aware of. The bowden shouldn't let it fold up like that. The pressures are intense (typical 10 to 20 pounds of force on the filament) even in normal printing.

Your bowden needs to go all the way down into the white teflon part. The part below the red circle. The bowden can catch a few places on the way down. Because of this I hate that aluminum cylinder that you circled. I recommend maybe drilling a few holes in it so you can see when the bowden passes through there. Alternatively, because the white collet that holds the bowden in has sharp knives inside, you can look carefully (with reading glasses maybe) and find all the marks on the bowden. Use a sharpie to mark the farthest mark from the end. And when you insert the bowden make sure that mark gets down to the blades in the collet. Or maybe measure the distance from the top of the head to the white teflon part top. Mark the same distance onto the bowden and use that to be sure the bowden is all the way in.

It moves the stepper until it hits the limit switch and if it never hits the switch it assumes it's the switch and not the stepper. It figures the operator is smart enough to notice that nothing moved. Also if you go to ultimaker.com/er05 it specifically mentions that perhaps your steppers are not moving. 90% of the time the failure is caused by debris. It's common for one stepper driver to fail but this is the first time I've heard of all 4 failing. Maybe the printer was printing in a hot (> 25C) room and the drivers burnt out one at a time during a print and no one noticed until after all 4 burnt out. In the Netherlands where these printers were designed and tested, 25C is crazy hot. They think you will die if it gets any hotter than that, lol. They bicycle everywhere in shorts in the winter while it is snowing. In other countries, <25C is time to put on your winter clothes (e.g. a sweater). So these printers don't work great >25C. Some people put the printer on it's side (it will print fine on it's side or even upside down) and then remove the cover and put a fan blowing on the electronics. I've never had to do that.

Note that if your print is very tall, moving up another 30mm might go "outside the bounds" of the printer volume and so it would just ignore that command and display an error message and defeat the whole purpose. But anything at least 30mm short of the full height would be fine. Yes that text at the end was to fix a bug in older um2 firmwares but I think the bug was fixed long ago. Still, probably half the um2 printers out there have older firmware with the bug.

If it happens twice in a row, maybe you should post your gcode for me to look at. Or at least the last 30 lines of gcode. 99% of the time I ask for the cura profile (file, save profile) but this time I think I want to see the actual gcode.

This happens to me also occasionally and it's very annoying. If you just print it again I think it won't happen the second time. It doesn't happen often enough for me to figure out the cause. It doesn't actually extrude during this time as far as I know - it just melts the part. I've been there when it happens and I cut the power and push down the bed but it's often too late. I've been tempted to manually add a Z move upwards at the end of the print job but never done it. Since your part is so small, you could print a few of them in "one at a time" mode and only the last one will get ruined but again, I find this doesn't happen very often.

@Allrounder - his steppers don't move. Ever. The limit switches are fine. Well the simple fix is to get another PCB. It looks like they are pretty expensive (over $300 USD). You can get a chinese version from aliexpress for $90 USD. It might need changes to the firmware. Not sure. The stepper drivers may be different but should work. And you'll probably have to wait a month for shipping. You could probe the pin with a scope that pulses the stepper and verify that the problem is the stepper driver and not the arduino-like chip. But unless you want to do some serious surface mount soldering (needs special equipment) you'll need to replace the whole PCB either way. I don't see any easy solutions.

I just don't understand how all 4 steppers could fail at the same time. Are they all plugged in? Well keep in mind it's never the steppers but the stepper drivers. Also try a factory reset. I don't see how that could be it but what happens is this: each version of firmware stores a few things (like steps/mm for each axis and about 200 other things) in a special part of memory that isn't affected when you load a new firmware. Each newer version of firmware had more data stored in there and the newer versions all know how to read the older data formats but not vice versa. So if you ever install an older version it's good to do a "factory reset" which resets all of those values back to defaults. Unfortunately it then makes you level the bed which won't work for you and may cause you to be in an infinite loop - not sure. I think you can just click through it? Probably not. Still I think it's worth a try: "factory reset".

There is a common problem with this board where the relay K1 fails. It's pretty easy to fix but if K1 fails then the bed and nozzle won't heat up. Are you absolutely sure the bed heats up? Did you feel it with your hand? The next most common failure is stepper driver but never all of the stepper drivers at once. Try to heat the nozzle to 180C and then do the MOVE command to move the feeder motor (some firmware versions won't let you move the filament until it gets above 170C). And again - maybe you have the wrong firmware. Where did you get it? There are many versions of Marlin and different printers have the steppers on different pins. Again, please try tinker Marlin - I linked to it above.

Did you try printing at 25mm/sec? Just a s a test? That's what helps these for me.

Sounds great but I rarely use the .25. It clogs easy. It's tricky. But mostly it prints slow. Real slow. 4X slower than the 0.4. But of course you have to change the slicing settings to get a reasonable speed from the .4 nozzle (wider line width, thicker layers). Your part has no detail (no lettering, no ridges, no small holes, no little bumps, no gridwork) and so I'm not sure why you would want to use a .25. I mean it will probably look a little nicer so there is that.

It appears your CAD model has lots of inidividual, short planes on that outer wall. So the outer wall is curved? I'd try reducing the number of triangles output to STL in your CAD software. Also there is some kind of resolution setting in Cura (I forget what it is called exactly) that might help if you increase the resolution but it might print worse because it will have more gcodes and many printers have problems if there are too many movements per mm (they stutter as the cpu can't keep up with the computations).

No. 98% sure you can't. It's about how the slicer works, slicing the triangles in the 3d model into lines and then linking the lines up into loops. That's just one of the basic steps. Without the loops, the slicer wouldn't know what's "inside" the model and what's "outside". You'd have to change the cad also to create non-manifold STL files where the models joined together. So you'd have to change both CAD software and also Cura.

I suspect something is broken. It's not your fault. You can't break it so easily. However I have many times recovered an arduino based printer that wasn't working very well. But I was doing it through USB. You used that programmer thing which I would imagine is more reliable. Where did you get that firmware? I'm thinking that's the wrong firmware. It's kind of your only hope. I'd try the tinkermarlin firmware since it is better anyway (has many features) and I know it works fine. Make sure to get the UM2+ (not extended) version (second to last hex file): https://github.com/TinkerGnome/Ultimaker2Marlin/releases/tag/V17.10.1

I love big reels. Many vendors sell 5kg spools. There is no reason to use Ultimaker filament on an Ultimaker printer. Go for it. I put the spools on the floor and put the printer towards the rear of a table. I've built spool holders but now I usually just put them on the floor such that as the filament is unspooled, they roll towards the wall. I also have a UM2go on a shelf with a spool holder on the shelf below. That works well also.

So I guess one workaround is to run cura 4.X, save a gcode file to a particular folder, exit, then launch latest cura and now you have a permanent default folder.

For me it's stuck on a particular folder that I was writing gcode files to a year ago.

I'm pretty sure not. You could play around with "combing" which controls retractions in situations similar to this and see the result in PREVIEW mode. Raft is rarely used in Cura. It's an old feature from before people found better tricks to avoid parts warping off the print surface. Raft is more a last ditch effort. There are better ways to get your part to stick to the bed depending on your bed? For example if you don't have a heated bed and are using blue tape - you might not realize that you have to remove the wax from the tape using isopropyl alcohol. Or if you have a heated glass bed you might need magigoo. Or you might not be squishing your bottom layer enough. Anyway, the point is, Cura developers probably haven't paid much attention to raft because probably none of them have ever needed it.

On Ubuntu Cura used to default to the most recent folder saved to. I think 5.0 or 5.2 was the last version that did that. I have the same problem now on Cura 5.3 and 5.4. The "last saved" folder doesn't update and has been fixed to the same folder for about a year. Quite annoying.

I get holes and bumps but barely notice them as I don't care about them. I'm not sure if I get barely any or lots as I really don't pay much attention. But when I *did* pay attention, like 5 years ago, I seem to remember that if I printed slower they went away. Very slow, like 25mm/sec and also I think possibly thick like 0.2mm layers.

If you want the top most surfaces (the top most and the flat surface inside the round hole) to be extra smooth then you can try out a feature called "ironing" and with a 0.4mm nozzle. Ironing needs some experimenting. For example the guy who invented it (neotko on this forum) likes to do about a 10% flow rate during the ironing phase. He is a world expert on ironing because he prints and sells hundreds of hotel-room-key-tag things with the hotel and room number on them. And they need to be very flat. So if you decide to use this feature, try it on a small 1cm cube and try different settings.

I'm definitely leaning to theory 2. You did finally post the project file by the way - that was VERY educational. I am looking at your prints with all new ideas now. What I thought was overextrusion was just typical 0.25mm nozzle being so small I couldn't see the lines in the top surface. Which is what people like about that nozzle of course. If it's theory 2 then try simply doing thicker layer height. Maybe 0.1 or even 0.15 which matches the resolution of the 0.25 nozzle more closely - although that's kind of irrelevant. I'm thinking that it is extruding so slowly that the feeder is barely moving and so it comes out it bits and spurts. Sort of. This is a bad explanation of a complicated process where the filament sometimes sticks to the part and sometimes pulls out too much out of the nozzle and you get that fuzzy surface. Why are you doing 0.25mm nozzle? Any reason? Can you go to 0.4? 0.25 nozzle is quite tricky. I've got some pretty amazing prints out of it but... it's not trivial. I had to play with so many things.

So I am split between 2 theories: 1) Extruder is doing wrong steps/mm and is off by 2X. This is quite believable since 2X changes in steps are a thing that has happened before but I'm thinking this is unlikely because if you are still on UM2 (non plus) firmware then I would expect the feeder to rotate backwards but maybe you just need the "reset to factory defaults" because sometimes it takes "old" parameters from previous versions of software (like steps/mm) and "reset to factory defaults" tells it not to do that and just set things up fresh. 2) 0.06 layer height and 0.25 nozzle is just too insane. I'm thinking you just can't get good results with those crazy values. And on top of that, your part has no fine features. So using a 0.8mm nozzle and 0.3 layer height will give you pretty gootd precision (but it might not look as nice?) and will print much faster. Right now your print is 20 hours which is... A LONG TIME! With a 0.6 nozzle, only 20% infill, and 0.2 layer height (I'd probably even go for 0.8 nozzle) it will print in 3.5 hours. However you might not like how the quality is of the surface. Still it will be better than what you have now.

Oh. After it does the firmware update, try "reset to factory defaults". This will reset the steps/mm for the extruder to the proper value. It will also (unfortunately) make you level the bed again.