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@timcnc1 - sorry I don't know exactly what it says. "save project" "save project as". Something like that. They may have changed it a year ago and I still probably would have it backwards. Please save the project and post that file here.

This sounds like a Cura question so I moved this topic there. It's probably a problem with your model but to be sure, please post the entire project which will include your model and your profile and settings and so on. In Cura, do "file" "save project as" and then post that resulting file please.

What you didn't do was answer Carla's question which is super important. Watch the autolevel procedure.

The "active leveling" is performed initially on the right core extra slow. Watch it do it - it should go extra slow and touch the glass and then I think maybe it does it a second time possibly? I forget. But almost immediately when it touches the glass it bounces back up. Then it does the same thing on the left core. The right core should stick down 1.5mm farther. +/- 0.7mm. You can look at the log files to see what the difference is. Actually first search for "height difference between nozzles is too large" as that is the message that occurs right when the error happens. Write down the date and time and *then* search for "peak" and "Preliminary" and look to see if even the passing tests *almost* fail. But lets backup here: 1) First make sure it is performing the leveling properly. Often it does not. Often the leveling sensor has issues or there is electrical noise messing it up from some equipment nearby. So watch the first to leveling tests where it does the right and then the left nozzle. It should just touch the glass and jump away from the glass. The two failure modes is it touches the glass and keeps moving down for several more seconds. Much too long. The other failure mode is it never reaches the glass and thinks it did. So let us know if this is your failure mode. 2) Another failure mode is the switch is broken as you mention and it tests the left core twice (or the right core twice). 3) The most common failure is probably that the cores are different heights. You can put the left core down and measure the difference in height between the left and right (when clean). It should be about 1.5mm. Sometimes it isn't. Sometimes a core doesn't slide down properly and settle in and is too high. Some cores are just bad so you could try a different core. Try both AA cores to see if you still get the error. Or try an AA and a BB if you were already doing two AA cores. More info here:

It looks like it is happening only on the bottom layer? Correct? 1) check the glass carefully - feel for holes in the glass. Sometimes when removing a print, the glass spalls and a chunk of glass ends up in the print. These problems may be occuring over those "holes" in the glass. 2) It looks like it's not touching the glass in those spots. It looks like possibly some mild underextrusion or maybe you just need to add some sort of glue. Glue stick works pretty well. Best results are with an extra thin layer - apply glue stick then using a wet tissue spread the glue around evenly (and removing most of it). Or you can mix wood glue with water. Use 10 to 20 parts water for 1 part elmer's (or other brand) wood glue. Mix it well and paint it on the bed with a cheap paint brush. Heat the bed to normal printing temps (60C for PLA) until the glue dries (takes usually about 4 minutes). Or buy Magigoo. (google it)

Instead of cutting speed in half you could raise the temp by 10C. It might make overhangs a bit worse or bridging but it will certainly let you print faster (meaning not have to slow down). Or you could look into purchasing a more powerful feeder possibly. Like a bondtech feeder for example.

Yeah - those are pretty badly underextruded. I mean I've seen much worse but that's about 20% underextruded. You are going to have things like outer walls not connected to the rest of the part. @GregValiant posted a nice picture (many posts back) where he zoomed into another of your photos and showed those gaps using red and yellow lines (he probably used mspaint?). You may need reading glasses to see up close but your top layers are nicely showing underextrusion. If you cut the speed in half and increas the flow to 105% that should fix it. Never go over 110% flow (assuming your extruder is calibrated properly where 100mm of extruding moves the filament 100mm when hot end is removed). If you are at 110% flow you are near the point of complete grinding/failure. 105% is safe enough but indicates something is wrong but at least you can probably get good prints.

The eeprom on the core is supposed to have a string on it: "CC 0.6" as ascii characters. Either the eeprom flipped a bit (space is 32, null is 0, 32 is 2^5 so it's like that single bit is bad) or there was a bad connection when plugging it in. Definitely try unplugging and pushing in the core more firmly a second time. Also it is possible to reprogram the core.

Don't judge over/under extrusion by the bottom layer. The bottom layer is affected much more by leveling. In fact it is desirable to overextrude the bottom layer. So typically the leveling procedure sets z=0 to be *below* the print bed by about 0.1mm. this is on purpose to get the part to stick well (really push/squish that bottom layer into the bed). Make sure you are on the 3rd layer before judging over/underextrusion. I recommend doing a small print - maybe 20mm cube with 100% fill and looking at the gaps between the fill lines starting on the 3rd layer. Then you can play with flow, temperature, speed live while printing from the TUNE menu (your printer appears to have Marlin firmware so you likely have a live TUNE menu where you can adjust some parameters while printing).

Oh. I'm embarrassed. This is not a bug. I should have had @KingOli post the project file here for me to look at before suggesting cura issues. The part that the skirt goes "under" is not touching the build plate. If you want the part to touch the build plate then the 4 portions that are over the skirt need to start at the same height as the rectangular portion that they are attached to. Or as @ahoeben says, you can set Z to a slightly negative value but to do that you have to first go into the cura preferences menu "preferences" "configure cura" select "general" and uncheck "automatically drop models to the build plate".

So there *is* a way to turn this feature off (or raise the temperature where it kicks in). It was discussed here:

You think your hot and cold ends are fine but I doubt it. There are just so many things that can go wrong. Try helping the filament by pushing it with a LOT of force - maybe 2kg of force just before the feeder. See if that closes the gaps. Or try fighting the feeder when you are printing at 10% feedrate. the feeder on a cheap printer should pull at least 5 lbs or 2kg of force. A decent printer can push 10 pounds (5kg) and a bondtech feeder can push with about 20 pounds (about 10kg) of force. Less than 5lbs/2kg is just a crappy printer or maybe something needs fixing on it. Similarly - if your hot end has any teflon in it, the teflon can get old. When it gets old it gets soft and any pressure squeesing it vertically can turn into forces that squeeze the filament tightly. I'm only covering a few issues. There's really something like 30 things that can cause underextrusion. The driver might be current limited - especially if you are in "silent" mode. The driver may be overheating - maybe the room is just too hot. There's still a LOT of other things that can be the issue.

It's hard to measure underextrusion by looking at a wall. 20% underextrusion looks PERFECT on a wall. You have to look at top surfaces. Or beter, do 100% infill so you can examine it on each layer and adjust your temperature and fan as you move. Can you see those gaps in your top surface? There should be no gaps. It should be more like this:

Actually the only thing I can think of is if the part is too big to slice and the parameter you are referring to is adhesion type, or brim or something similar where the size of the brim makes the part too big to slice. Could that be what you are talking about? I think for that maybe I agree that there should be a text message that lists the parameters that affect the size (I think there 3 to 6 parameters that can affect that maybe). Look no one is going to fix this if they can't duplicate an example. If there are multiple examples at least one example will give the developers an idea of other similar examples.

@benjamins94 And my point is that cura *does* tell you the cause of the error. It doesn't do it in words - it does it by colors and patterns. Red is a universal color for errors/problems. And if it doesn't that might be a bug so you need to tell us which error got missed. Again: It tells you by turning the parameter red if it's a parameter. If it's not a parameter it has other ways of telling you but you are convinced it's a parameter so we'll skip that part. Now it might be that it does *not* turn the parameter red and if so I'd like to know about it because maybe there is a bug. That's why we want to know which parameter you changed to get it to slice again.

@maggiolo72 Are you using PLA? Looking at that photo - ignoring that mess - the layer below has severe underextrusion. I'd say around 20% underextrusion. You need to fix that first. You are either printing too cold, too fast, or something is wrong with your printer. It could be the feeder isn't gripping the filament tight enough. It could be there is a constriction in the hot end. I could give you a list of the top 30 things that cause underextrusion on the UM2 printer but I don't think that will help you much. After you get all those gaps filled in on your top layer THEN look into ironing. neotko invented it and he has a business where he prints and sells many dozens of key rings per day. To hotels. Each plastic key thing is flat and has the hotel logo and the room number. So it's just like the print with the writing. He perfected ironing over hundreds of prints. So his posts on the issue are the most informative. I don't use the search on this page here but go to google and add "site:ultimaker.com neotko" followed by ironing or neosanding. But before you try ironing you need to fix your printer. Hint: it's not the belts, lol. It's the hot or cold end. Or your settings (too fast or too cold or both).

Sounds like a bug. It would be good if you guys could post this as an "issue" on github. Unfortunately you need a github account but it's easy and free. Then post the issue here: https://github.com/Ultimaker/Cura/issues Also include the project file (which contains the STL, and all your settings) that reproduces the issue. The developers are very busy and if they can't reproduce your issue the first time they are likely to move onto another issue. To get the project file do "file" "save project file". Also it's best if you verify that the problem is in the latest copy as they might not know if it is something that was fixed in the latest cura.

Look at the ironing feature in Cura. It was made for this. Also search for posts made by "neotko" (who invented this) along with the words "neosanding" or "ironing".

Yikes. Did you update the line width in all those profiles? If you update cura I think you will lose all that work. Unfortunately. Wait - I don't think there is such a thing as a CC 0.4 core.

I think Cura usually colors the parameter red (if it's a parameter). Otherwise usually the model is outside the print area and has zebra stripes to indicate that the model is the problem somehow.

It could be humidity, yes. When you first feed it through the nozzle (you can do this in MOVE command on the display under the "..." for the matial type) do you see any steam coming out of the nozzle? If so then it is too wet. If you hear sizzling, popping, really any sound at all other than the feeder, then it's even worse than simply too wet. You can dry PVA. Look in cura at how many meters you need. Unspool that amount onto the print bed and place the spool on top (no need to cut the filament). Then heat to 70C, cover with a few towels, a pillow, sheets, paper towels. Something. Some kind of insulation. Even some cardboard. Leave it like that for 2 to 5 hours and it should print fine. To dry the whoie spool it needs something like a few days as it takes a very long time (days) to get the humidity out if it is deep in the spool. Easier to just dry what you need. Going forward you want at least 1/4 cup of color-changing-dessicant in a ziplock bag with your spools of PVA or Nylon. You can buy it by the liter/quart. When the color changes you have to heat it back up on a heated bed or in the microwave (in a non metalic, non meltable container such as a glass bowl).

Yes. Make two models that don't intersect with each other. You may have to raise the Z value of the text so it sits at the right height. I just did this for a print 2 days ago. You can do this even if your printer only has one extruder - in fact that is the default where the same extruder gets assigned to all models. In my example I had 2 extruders with 2 different color filaments. I didn't use the ironing feature but it would have been easy to do so.

By default I believe the feeder won't rotate at any given moment if the temperature dips below 170C. This line of code in Configuration.h: #define EXTRUDE_MINTEMP 170 So one option is to change that line of code and rebuild Marlin but this is not trivial and would take an experienced programmer maybe 2 to 5 hours the first time (just a few minutes the second time). I did post how to do this: https://community.ultimaker.com/topic/16856-how-to-build-marlin-the-way-tinkerghome-and-ultimaker-do-it-if-you-have-windows/ HOWEVER there is another option. You can enable cold extrudes with the gcode M302 (allow cold extrudes): M302 S0 So you could add that gcode early on in the program - I guess just before you first move the extruder I'm not sure what you mean by "um 2 have limit". Are you talking about the TUNE menu? Or Cura? If the Material settings on the printer itself have a lower limit as well then you can go back to cura and go into "machine settings" (tricky to find) and change the options on your gcode flavor to Marlin instead of "ultigcode". This will let you set the nozzle temp in Cura (or you can do it by hand editing the gcode. Normally, for UM2 printers, the temp is controlled by the filament type on the printer itself but most printers (including every other Ultimaker printer type) don't do this and you control the temperature in Cura.

Ideally the profiles should have been algorithmic. Where there is code that adjust parameters based on the user's needs. For example if the 0.1 layer height profile uses a print speed of 70 and the 0.2 layer height profile uses a print speed of 60 then the 0.15 layer height profile should automatically choose 65 using the simple rule of linearity (which is really easy to do in code). That way people can do 0.17 layer height and everything just adjusts. Fortunately, in reality, changing from 0.4 to 0.6 nozzle just means changing line width to 0.6 and you don't need to change anything else (no need to change fan speed or temperature or the other 500 parameters). I do recommend changing wall width to a multiple of .6 such as 1.2, 1.8, 2.4 etc. Which could also be done algorithmically. Also in reality, all the 30 or so nylon materials can all be print with the same profile regardless if it's CF filled, GF filled, plain, colored, etc. yes there are slight variations in temperature but that's not always necessary to adjust and still get a really good print. This is true for most materials. Even PLA and PLA Tough can be printed with the same profile (although UM did really tune the tough one so I'd use that for best results).

Just use the AA 0.4 profile and change line width to 0.6mm (all the line widths - there's a few of them - just put "line width" in the search box). done. Also when you go to print it will complain that the cores don't match. Just hit the ignore button. One reason those options go away is because they would have to create them all. That's about 6 new profiles just for the S5. And another 6 for the S3 and so on. Another reason is that the CC 0.6 was meant for abrasive materials so they concentrated on those profiles first.