baymaker

Hi, Saw your message, I may be interested, What's your current (and the printer's) location ? Let me know, Thanks, Max.

From what you're telling me, it seems like you had that issue but the opposite way (you had the teflon sitting too low instead of too high). So you may have had issue with the bottom of the teflon heated too much or not having enough pressure applied to it rather than the spring putting too much pressure on it .. I usually don't print at 0,2, but when I did (and the teflon was mounted the right way) I never had issue of infill lines not touching, so I'm not sure what problem you're talking about that is specific to ,2 layers.

Huh, too bad, but I saw on a different thread that some printer came from the factory assembled the wrong way on that part, so depending where yours was assembled, you may have had this issue from the beginning .. If so, it would probably be worth it to replace the teflon coupler, even if not used that much, it had probably been under a lot more stress and pressure that it should have, which may have made it degrade much faster ... I'm still recalibrating everything, but I've had a couple prints coming out pretty great from the printer since modyfing this. Maybe I was having a different issue, but the pictures and problems experienced where very very similar (at least from the pictures I saw).

Ok, I don't want to celebrate too early, but I've been printing for about 2 hour now, and not a single issue, perfect layers, smooth as can be. So, still not fully celebrating as I'll wait for this part to finish printing, but I think it's safe to fill the fridge with champagne just in case !

This thread is pretty old, but I feel like I may not be the only one who had that issue, and didn't find this info clearly explained elsewhere (but only parts of it on different threads). I very strongly believe (still under investigation but the first results are pretty encouraging) that this gap is actually crucial (which is why you should follow the assembly guide when replacing the teflon coupler and first place the teflon ALL THE WAY DOWN into the nut, then screw the nut into the nozzle until you get 1mm spacing between the teflon and the nut). From what I've seen so far, I think that without this gap, the spring is applying a too high pressure on the teflon, making it deteriorate insanely faster, which then will most likely create printing issue, which may lead you to unmount half the printer replace all the components you can and slowly make you loose your sanity. Happy printing !

Feels a bit stupid to rewrite the whole thing, and I haven't tested it yet, but this issue COULD be caused by an improper teflon coupler mounting, putting too much spring pressure on it, creating way premature use in the teflon coupler, generating the issues we've been experiencing ... I'm working on it right now, and will post the results if I get any, in the meantime you can check page 56 of the assembly manual (am I the only one discovering the very existence of that holy grail of a manual only now?!) on the head assembly, don't know how you did it, but I replaced my teflon coupler the other way around (nut screwed into the nozzle first then teflon slide into it .. ). This could be the cause of our problem .... Will update as soon as I've been able to try out my theory !

I THINK I FOUND IT !!!! I just disassembled the head yesterday and replace the teflon coupler that was roughly a month old (yeah, I'd been printing a lot but still), and was a bit surprised to see how used it already looked. With the new one I've been able to print again, and it looks pretty perfect, but I just found out that the assembly manual (actually I first just found out there was an assembly manual for the UM2 available to the public !) that the teflon coupler IS sitting too high into the nut. I believe that the reason for that is that 'for me at least), when you replace your teflon coupler, you may first screw the nut back into the nozzle, then try to put the teflon, and soon enough, nothing works on the printer anymore ... I may be wrong, but I believe this is caused by extremely premature use of the teflon coupler caused by too high a pressure from the spring. When checking the manual, I saw that you're actually supposed to first place the teflon back into the nut (where it should be able to slide in all the way), put that back into the metal plates, and THEN screw it into the nozzle, stopping once you have a gap about 1mm between the teflon and nut ... I just stopped a print I had going on (which was turning out pretty perfect so far otherwise) to dismount the head and do that adjustment. I'll launch a new print right after and let you know how it goes. Maybe this won't make any difference, but that would explain why people with new parts that they just replaced are experiencing issues, and could explain the randomness of who's experiencing the issue (I also saw on another thread that some people had this mounted wrong from the factory, so that could also explain the issue on brand new printers ..) I'll adjust it all and keep you posted on the results. Hopefully that will FINALLY solve it !

Would there be a way to "group" all the topics related to this issue ? I've found 3 "active" ones so far, and we pretty much all have the same issues, with the same fix suggested. I'm thinking it would probably be more efficient if everyone focused on a single topic page, that way we could probably avoid repeating some information, and group all the information in one place, and who knows, maybe the 39th page will be the one where we finally come up with a solution ! I found this post : https://ultimaker.com/en/community/view/9513-underextrusion-need-help-with-this-one?page=2 , and Illuminarti's answer got me thinking that maybe my print head assembly is wrong, with the nut being screwed too far into the nozzle (all the way down, without forcing, but without leaving a full turn unscrewed as shown in the picture either). Because of this, the teflon is not sitting as far down, and maybe this creates some gap somewhere, that could slowly get filled by melted plastic, which would probably affect the flow in a pretty "random" way, that could generate the fluctuations we see in the infill ? I just took apart and reassembled my print head yesterday, so I'd like some confirmation or advice before getting back to disassembling it again, but I'm thinking that maybe this could be what's causing our issue (which would be awesome !) If nobody knows about this I'll give it a shot this afternoon and post my results.

While I was crying watching my printer staying idle, I stumbled upon this post : https://ultimaker.com/en/community/view/9513-underextrusion-need-help-with-this-one?page=2 The answer Illuminarti provides shows an assembly of the printhead/nozzle different than what I have going on now. I just dismounted everything yesterday and cleaned it out and reassembled it, so I'd like some confirmation before going ahead, but could that gap between the nozzle/nut make a difference ? And generate the kind of issues we've been having (like putting a gap "somewhere" inside that assembly, in which the melted plastic would go, slowing down the flow from time to time, randomly, explaining what's our problem ?) When I first changed my Teflon coupler about a month ago it seemed to make sense to me to re-assemble the nut screwing it all the way down (without forcing) into the nozzle, but I could very much be wrong, I was thinking more in an "Ikea assembly" kind of logic, and maybe that's not a good fit in 3D printing Anyone has some info on this ? On new/untouched printer, how far into the nut does the teflon coupler sits ? I think my old one used to sit a bit further into the nut, so maybe that's the issue, but because I just dismounted the whole head yesterday, I'd like some confirmation before getting into this again.

I'm not sure now that I've been reading some many issue/fix posts, but I was wondering what firmware was everyone experiencing this running. I know that I would probably never have done the update if I haven't changed the electronic board, so I was wondering if maybe that could be linked to this ? I'm going to take the head apart this afternoon, not sure what I'll be looking for but it can't hurt to give it a look, especially since the printer is not working in the meantime ..

Man, I was so full of hope when I saw this post going on for 38 pages, thinking that finally someone else was having the same issues as I did, and hoping that I'll find a fix in there, but unfortunately, I just got to the end, and no luck so far ... . I'm really struggling to find what could be going on wrong and explaining these issues .... As most who have this problem, I've already tried replacing ptfe coupler (like 1 month ago maybe), check the bowden tube, opened the feeder to clean it all up, but so far, nothing has made any kind of improvements ... What I don't really understand is that this issue just "appeared" out of nowhere, that some models would print perfectly fine 2 days ago, and now I can't get a single layer for a "large" flat object to print decently ...

Also, a couple of other "maybe linked" issues I've had so far : - Playing with the feeder tension. Took me a while, but I think I finally have the right level of tightness (and as soon as I'm printing reliably again I'm printing Robert's feeder and throwing this insanely designed one away ! ) - My belts seem to be tight, however I 've noticed an increasing amount of "black dust" beneath some of them. At first I thought that it was because I increased the traveling to 250, but it seems to be still going on. I can't see any obvious "use" on my belts, the teeth are still here and pretty sharp, but I'm not sure how bad they can get before becoming an issue. - Every now and then, I get a clog right at the beginning of a print. After investigation and an significant amount of filament wasted, I found out that the "tip" of my filament would make a "blob", which seems to force its way through the bowden tube when being retracted and still a bit hot, but that won't slide through when being pushed back and cold. What could this be coming from ? I'm worried that the answer is going to be "Teflon coupler", that I replaced way less than a month ago... Could that explain some of the under-extrusion with this blob slowing down the extrusion after retraction ? I can post a picture of the way the filament tip looks when this happens. I can post pictures of my failed print, but the issues are very very similar to the ones already posted here. A bit more less regular, more random I'd say, but the very same looking failed lines, and the same frustration in the end ... Edit; just tried a new print, and lucky me, I get this issue from the very first layer now, before any retraction, so I'm guessing my blob issue is not related ... Any suggestions ? The blob I mentioned (I usually only have the upper part, the lower one staying inside the nozzle ..) First layer, and the issue is already there ... "yeeah" .. And keeps going on, after 5 bottom layer, a couple of infill ones, and 7 or 8 of top infill

Hi everyone. I'm in the same situation as Esteban, getting pretty frustrated after trying to fix every single issue I could think of. I changed my ptfe coupler a couple weeks ago, along with a new electronic board, so I updated to the latest firmware included in the last Cura's release (the most unstable one I've seen in a long time, but that's not the issue now), and from then, nothing ever worked properly again. I'm getting the same kind of random underextruded lines on top infill, no matter the amount of layers. I tried different temp, different speed, double checked the filament diameter, tried different feeder pressure level, re-leveled the bed something like a thousand times, oiled every possible moving part, and ... nothing ! Well it prints, but with these random issues showing up here and there. I'm using toybuilders white pla, which I've used for several month now, never had an issue like this (does get brittle around the end of the roll but no enough to be a real issue), and no matter which roll I try the issue is the same, over and over again .. Couple of questions : - could it be something linked to the latest firmware ? Should I do a factory reset ? I was told when I received the board to update it as it was still a pretty old one on there, if I do a factory reset it will come back to this version right ? - how are there so many people having this same issue (apparently about at the same time), with both completely new and "used to work" printers, without any solution appearing ? - What could explain that the first layers/small parts print fine, but then suddenly it starts having issues during the infill ? Anyone able to provide any help would be much appreciated ! Thanks, Max.

FINAL EDIT : This problem actually solved itself, as I ended up finding out that withthe new board I got, the electronics are wires in a different way that makes the rear fan only turn on when the nozzle if hotter than 40° ! (This is an awesome feature ! ). Thanks to anyone who took a look anyway, I'm letting this here in case someone had the same kind of issues, but if the moderators want to remove it, go ahead too EDIT : The firmware is now updated (through the 15.02 version, couldn't manage to do it with the 16 one ..), but I still can't get the main fan back on. Anyone has some insight on which wire to check ? Any connection that could be faulty somewhere else ? Also, is it safe to print like this, or am I going to run into overheating problems real fast ? I don't want to risk damaging any other parts of the printer, but I'd like to have it up and printing again as soon as I can ... EDIT 2 : I've checked the connectors from the fan that are inside the black mesh. Even when playing a bit with them, I can't get the fan to turn back on ... So I'm guessing the issue is somewhere on the PB or its connection (which would make sense as I didn't had that issue before ..) Anyone knows which connector I should be looking for ? EDIT 3: I tried switching the wires from the sides fans to the rear one. The side won't turn on, so I'm guessing no power coming from the rear fan connection ... Could this be something on the PB ? (which is pretty mulch brad new :/) Or just a cable to replace (can I cut it/pull the coating or do I need a new one ? ) Also, how safe is it for the components to run the printer without the rear fan on ? Otherwise can I run it with a side fan disabled by switching the wires ? No risk of damaging the fans with the voltage or something (I have few to no knowledge in electronics) Thanks for any help you can get me ! Max. Hi everyone, After some issues with a faulty power cord that ended up damaging the Arduino board connection on my UM2, I've tried replacing it this morning. A bit tricky to move all the wires from a board to the other, but I got there. Everything is plugged in correctly, but not everything is working properly ... I have two main issues at the moment : -I've been told by the support that I should update the firmware of the board before running a new print. The printer connects to windows (I get the "new device" sound when I plug it in/out), but I can't get the printer to connect with Cura to install the new firmware. I tried with Cura 15.02 and the newest 16.01 (which looks awesome, even more frustrating not to be able to try it out !), and so far haven't been able to have Cura recognize the printer. I tried with auto port or selecting the one it connects to (COM10), activating/deactivating the port, rebooting the computer, and tried every baudrate combination available...Nothing worked so far. It either stays idle, waiting of the printer (when it's set on "auto"), or tells me that the printer wasn't found (when a specific port is selected) .... -The "main" fan (he one behind the nozzle) won't turn on anymore ... It normally starts running as soon as the printer is on and keeps spinning as long as the printer is on, but so far it either won't turn on, or will turn on and shut off randomly ... I double checked the wires connections on the board and couldn't see anything wrong (I may be missing something though .. Not sure which connector controls this fan). From what I understood this fan is kind of a big deal as it prevents the head and electronics from overheating when printing, so for now I'm stuck with a "brand new" printer that I can't use ... I'm unsure how "safe" it would be to use the printer as it is now (old firmware+cooling fan not running), and would definitely rather wait for everything to be back and running before trying a new print, but if anyone has some insight on how safe this is or not, let me know Thanks in advance for any help you can get me, this community has already been really helpful to me in the past, hopefully it'll save me again this time Max.

Swap_at_Z IS the solution !! Slice your model a first time, with bottom infill enabled. Save that gcode, uncheck the "bottom infill", load the plugin, set its start and end value to keep only the infilled bottom, and BOOM, problem solved !