gr5

Boot sequence should look similar to this (I've also attached serial cable to my olimex lime2 and I've captured much of the boot sequence but not the first few lines - this is from someone else): Later on in the boot sequence (maybe already) you can hit enter key or ctrl+c or something like that to get a UBOOT prompt which has lots of commands. Again - google "lime2 uboot commands" or something similar.

Oh and the stepper is probably just fine. They never seem to die. They are much tougher than you might think. They should never need to be replaced.

Yeah that's familiar. I've heard this before. It has to do with the belts and also the pulleys I think. You can replace the belts at some point but I recommend you ignore this for now. Try printing 2 thousand more hours of printing (8 hours per day, 5 days per week, for a year) first.

If it gets the error before the nozzle touches the glass then the sensor is failing. Check the 2 wires inside the print head that go to the sensor board. When you open the front of the print head, the sensor board swings down with it. Check those wires (very gently tug). Also keep radio frequency noise sources at least a meter away from the printer (e.g. cell phones, microwaves, laptops, raspberry pi's, electric motors). Do you have the latest firmware? A year or two ago UM improved the leveling software. There is also a leveling sensor test in the maintenance menu. If it passes, test it a few times. If it fails there then that is good as the problem isn't intermittent and you can experiment. Talk to your reseller - they might know much more than me.

Yeah, that's toast. If the problem were a little farther along - for example if it gave up searching for a boot image after a few tries then I'd say you can probably fix it. But if it stops after DRAM then I think it's toast. You can google "lime2" and "won't boot" and "DRAM" and learn more but I think you need to contact Ultimaker. I don't recommend trying to buy your own lime2 board as the UM board has some customizations (some connectors removed and this is critical for it to fit and I think a different USB connector). So you should contact your UM reseller. Unless you have lots of time and not much money and also happen to have surface mount soldering equipment. In that case, message me. I have some notes somewhere about what parts to remove/change. Actually if you are an SMB soldering expert you could just try changing out the DRAM chip.

So the dots - the impressions in between grinding look perfect. This tells me the feeder is working quite well. The problem is somewhere else. Most likely the core. How many cold pulls did you do to clean the head? I know you said it feeds fine but compared to what? Did you time how long it takes to feed a spot of filament down to the bed? Again - another quick fix is to just slow down the speed on the support. You've brought up travel speed twice now but travel speed has nothing to do with the printing speed of the PVA. You have to select the second extruder. Here are a very limited set of ideas of what the problem might be: 1) water. 80% of PVA issues are because the PVA absorbed moisture from the air. Just putting the filament on the back of the printer for 1 day is enough to greatly degrade the performance. One week at 50% humidity and it's time to dry the filament. When it has a *lot* of water you will notice steam coming out of the nozzle along with pva and you will hear hissing. When pva is dry, the bottom layer is transparent (versus snowy). The first tiny bit of extrusion is always clear because the filament has been drying for 30 seconds inside the nozzle but once you get printing it gets more snowy. the entire bottom layer needs to be 100% clear. 2) Clogging or partial clogging. At normal printing temperatures, PVA caramelizes into brown or black gunk in just a few minutes (like 15 minutes). That is one reason the inactive head must cool down while waiting. This can make the nozzle thinner (say 0.3mm) and when you print a lot in a row without letting the pva escape it will build up pressure until it slips in the feeder. Occasionally it slips enough to grind a bite and complete fail. Partial clogs can also be when a chunk of brown pva farther up in the nozzle ends up in the narrow channel but it sounds like this is not your issue. 3) Feeder - it could possibly be the feeder. I doubt it but the test is very easy - with the filament far above the head use the MOVE feature on the printer to move the pva up and down and then fight it with your hand on the back of the machine. The feeder should be stronger than you. It can push pva with about 10 to 15 pounds (5-10kg) of force. 4) Core - there are many things inside the core that can go wrong. These are rare but it's worth trying a different core sometimes. 5) Bowden tube - after printing a few kilometers (not sure how many spools that is - 10? 30?) the friction in the bowden can be a problem. 3dsolex has extra slippery bowdens although the ones from ultimaker are cheap and work just fine.

I'm glad you figured it out. That photo is classic - that's exactly what it looks like when the nozzle is a little too high off the bed on the first layer.

In cura enter "speed" in the settings search and click on core 2 tab. What is your support speed? Definitely don't slow down the travel speed. You want the travel speed at least 150mm/sec. Maybe 250mm/sec. Did you check the print head fan? What you describe is common if the print head fan is broken. The middle fan - not the side fan.

The flow sensors are complicated. There are I think 4 different flow sensors for the S5 and none of them are compatible with each other. And you have to tell the firmware which sensor it is. So if you changed out hardware then that could be part of the issue. For now you can of course just turn off the flow sensor so you can at least still print. Can you explain more about what you did? Did you buy your printer from 3dverkstan.se? They are very knowledgable - good people there.

There are no known firmware bugs that would do what you see. But it can't hurt to update the firmware. There are tens of thousands of working UM2 printers and I've never seen this exacty cycling (although most people don't monitor it so carefully I suppose). Hopefully it just needs a little solder.

It's not cura and it's not the gcode file. I searched the whole file and there are no temperature related commands of any sort in there. Just fan speed. You set these on the printer itself. There is no option on the UM2 to cycle the temp. Normally the bed temp doesn't move by more than 1C from goal. So something is very strange here. Maybe a bad power supply. Does the nozzle temp also oscillate? This pattern is strangely repetitve. Is it possible it repeats once per layer? Some versions of the UM2 firmware reduce the power to the printed bed if the nozzle needs much more power than normal. I doubt this is the issue but it is a small possibility. So the nozzle would demand more electricity in the same repetitive pattern. Do you have a volt meter and know how to use it? I'd monitor the voltage and make sure it stays at 24V during these dips in temperature. It seems very unlikely that this would happen as well because the power supply is pretty smart and knows if it is failing and will turn off automatically. Most likely there is a bad wiring connection. Most likely it's where the connector is soldered to the heated bed. That connector can come loose. I'm not sure why it cycles like this but maybe when it heats up the connection expands enough that there is an open circuit and then when it cools down enough it reconnects. Do you have soldering skills? Do you know someone who does? This is a 5 minute soldering job. The bed comes apart quite easily. Keep track of where the springs and washers went. Be gentle with the cabling. Reflow the solder for all 4 connections.

oh good. It was some setting then. Probably one of the ones mentioned above. I'll mark this as solved.

First go into the cura preferences (not project settings). Go to menu item "Preferences" (or Alt+R). Then "configure cura". Make sure "ensure models are kept apart" is unchecked. Pay attention to "Automatically drop models to the build plate". You may want this on or off. Not sure. Alternatively you can click on each part and the move tool and set Z to zero. I haven't done this in years but I just played with cura a bit and I didn't use the "merge" feature. Instead I added both models, right clicked on each one and assigned a different extruder, then I right clicked on each and did "center". That seemed to work well. It looks to me like your "rocket" model should possibly be scaled down. You can click on it and use the scale tool and then recenter if necessary. I don't think there is any need to "merge".

You can do this with machine settings. Create a second machine with the different gcodes. You have to edit either python or more likely json files. There are quite a few people on here who have created their own machine settings. And most printer sellers have created these machine profiles as well. It's really not hard. In addition you can make the mesh for your different beds look different so you have a visual reminder of which bed type you are slicing for. @GregValiant - has done some customization - maybe he can mention where to find your file. What printer are you using?

I was going to say the same thing as greg. After checking that, please post your project file which will include your STL file in it and all your settings. The issue you describe is quite common but can be caused by a bad model or by what Greg points out. Also there is another cura parameter: hole horizontal expansion. Make sure that is zero. Also what CAD software did you use?

Oh and a small part of what I discuss here talks about connecting a serial cable to your printer. Again, it works for UM3 and S5 but I'm not 100% sure you can do it on the S3: gr5.org/unbricking/

You could switch it to manual level I suppose. I believe the S3 is the only printer where you can't ssh into it (I could be wrong - if you switch it into developer mode can you then ssh into the ip address of the printer?). But you can probably connect a serial cable directly into the linux board on the machine. You can certainly do that on the S5 and UM3 but the S3 has a different board. But that board probably has 3 pins for connecting Rx, Tx, Gnd. Just like the UM3 and S5. Then you can log into linux and change things. Smithy posted (somewhere on this forum) how to switch to manual bed leveling. You change one word in one file. This seems like a significant amount of work (and you will have to redo it every time you upgrade firmware) but compared to the pain that people are describing it should be easy.

I don't think this is the right project file? I opened it and it slices fine but there are no blue lines (travel moves) where you had those stringing-like lines. Evidently I need the exact project file that went with that exact photo where it had the problem. Maybe. Because that project file you sent just doesn't seem to match up with that part as far as I can tell. Maybe try printing it again but halt the print as soon as you see it doing what it did before?

I'm guessing your normals are backwards for the walls of that hole. The "normal" is what tells cura which side of triangles in the model are inside and which are outside. Did you create this model? If so you can fix this in cad. If not there are free programs to fix the normals. If this model is from blender google about the "remesh modifier". And also about "normals" in blender. More here: https://www.sculpteo.com/en/tutorial/prepare-your-model-3d-printing-blender/ If this model is from sketchup read this: https://i.materialise.com/blog/3d-printing-with-sketchup/ drag and drop mesh repair service: https://3d-print.jomatik.de/en/index.php cura mesh tools In the upper right corner of Cura click "marketplace" and make sure you are on the "plugins" tab and install "Mesh Tools". Then restart Cura. Now right click on your model, choose "mesh tools" and first choose "check mesh", then if that passes choose "fix model normals"

From the link that Schiavini posted - there are a few quick ways to get to detailed descriptions of all the APIs.

That sounds like a bit more work with uSD cards and tricky software to get the ISO onto the uSD but not too bad. I hope someone from firmware team can explain a better way. Maybe @CarloK knows someone.

Okay - I agree that it's most likely the model. I think it is probably the model normals. Here are some suggestions for 2 different CAD systems: repairing models If this model is from blender google about the "remesh modifier". And also about "normals" in blender. More here: https://www.sculpteo.com/en/tutorial/prepare-your-model-3d-printing-blender/ If this model is from sketchup read this: https://i.materialise.com/blog/3d-printing-with-sketchup/ There are also lots of repair services including a plugin for cura. But fixing normals is usually very very easy. Particularly in sketchup. Most CAD don't create bad normals. Normals tell Cura which side of every triangle in the model is "inside" and "outside".

I can think of about 8 reasons this might be happening. I don't want to explain all 8. Please post your project file (in cura do "file" "save project") and post that file here for us to look at. It could be the model. It could be your settings.

If you read above, there are some bad sliding blocks with this problem and it has been fixed. Talk to your reseller. Most likely they will send you free blocks and belts. Replacements. I got the replacements for my UM3 and it made a huge difference. No more problems and I've printed more since I got the replacements than before.

I hope you read my other two posts above. I reread your first post. That "curl" is indeed a little concerning. I have a hypodermic needle which is great - very sharp cylinder cut at a steep angle. Much better than a normal non-hollow needle which doesn't have sharp edges. Anyway I have a 0.35mm hypodermic needle and I use that sometimes to scrape the inside of the nozzle. Followed by a cold pull. I do the scraping as it's in the cool down stage for the cold pull and try to push those scrapings up into the nozzle for removal by cold pull. This can help restore a nozzle with a layer of toasted/black filament baked onto the inner surfaces.