chrisp

Are you using the stock spool holder that mounts on the back of the UM2? You might want to try out another holder that is free of tension/friction. I recently made one, or there are plenty of other designs. My filament was getting caught on the black netting just before feeding into the extruder. https://www.youmagine.com/designs/spool-adapter-multi-step

Nicolinux, Remember I posted here earlier that I had more than one issue causing my under extrusion. The main reason that I believe was the teflon fitting(pics are in an earlier post). It was deformed noticeably where it sits into the milled fitting. I had to use a 3mm drill bit to carefully open up a 2.5mm hole where it was deformed, to a 3mm hole, like it is supposed to be. That was the main cause of my clogs during retractions, which also caused my under extrusion. I started really seeing a difference in my prints once the milled fitting was adjusted along with that. Or maybe I'm just getting lucky again for the next few prints. 5 Hours 8 Hours

Don't look at that pic, it was an idea that failed. It made things worse. Illuminarti, When the milled fitting is turned to add more space between the Teflon fitting and itself, the nozzle moves up while pushing the Teflon fitting up, because it is sitting against the tip of the threads on the nozzle. I should have taken more pics, this just sounds confusing as hell, lol. Basically, the Teflon fitting sits against the threads on the inside of the milled fitting and nozzle.

Braddock, I fixed the Bowden issue by taking off the red clip, then pushing down the gray connector so that it is flush with the black plastic and the Bowden tube slides in and out easily. While holding the gray bushing in place push the Bowden tube all the way down then hold the tube in place while you slightly push the gray bushing up until it gets tight then put your red clip back on. Mines been holding in place for about 15 hours worth of printing without budging. the gray bushing sits a little higher than usual, but it actually works. That's a crazy neat print you got there!

Haha......Nice! Here's the second test. A 5 hour print 80% fill that has failed 5 times. This is a bracket for the X & Y axis and I need 4 total. I even redesigned this object from a failed print. So far so good. On the left side are failed prints with 1/2 of them already in the garbage, but you can see that the failures are all at random times.

Nicolinux, Cool print btw! You can adjust it by using one of the allen wrenches that came with your ultimaker and stick it into one of the milled holes and turn gently. If its stuck or too tight, then don't force it. mine turned really easy. (I forgot to mention that I turned it while in place, in case that wasn't clear) I didn't have to take anything apart. The milled fitting has female threads on the bottom which screw into male threads on the nozzle. There is room to adjust the two because of this. Hope this helps you!

After cooling down from another night of dissappointment, I decided to try something else. I adjusted the milled fitting that the teflon adapter sits into so that there is a 1.5mm space. It was sitting at exactly 1mm for the spacing before the adjustment. I then leveled the buildplate because this adjustment changes the level that the nozzle sits at. I also took out the brim feature for the second try. My print went from this: To this: Perfection once again. I will be testing other colors and different length prints to make sure, because I have seen this before, then everything fails 5-8 prints later.

After carefully opening up the Teflon fitting to be the same size at both ends I put everything back together only to get this failed print! Same issue, nothing has changed. I'm totally lost here and there's absolutely nothing I can adjust to make a difference during the print to correct the under extrusion. And btw, I have another massive clog to deal with!

Ok here we go...... This clog was the worst by far. I started out by trying the change filament option via the controller. Nothing but grinding away the filament is what happened. I tried heating up the hot-end to 250 degrees Celsius and then tried removing the filament via the control panel and with a slight pressure of me pulling the filament with no success. I also tried move material but the filament was already grinded away inside the extruder. So what else is left? Taking apart the hot-end to see what is going on. I usually start by taking out the 4 side fan screws and I tie up the fans and brackets to the axis rod so I get them out of the way and prevent the wire shielding to get heated up by the heating element. Then I made sure to mark with a pen, the distance the Bowden tube is sitting inside the Teflon fitting. You can see the line marked with 3 dots which is not exactly against the Teflon, but close enough for reference. I then loosened all 4 screws out of the aluminum bracket holding the nozzle in place and every other time so far the Bowden tube has come out without a fight. This time was different. I had to heat up the hot-end starting at 190 and gradually moving up to 250 degrees celcius until I could finally loosen the Bowden tube up enough to pull it out. This is how the filament looked once I got it out. Then I cut off the filament so I could get the Teflon fitting to go back on the Bowden tube to make sure it is sitting all the way down. It's perfect no issues here. Next I took the Teflon fitting and observed it very closely only to find that there's a lip inside the end that is seated into the metal hot-end nozzle adapter. I took my digital caliper and measure 3mm in diameter for the opening at the top of the Teflon fitting and 2.5mm for the diameter at the bottom of the Teflon fitting. This I noticed once before but didn't think to measure it, but there is definitely some orange plastic stuck inside where the lip is and extremely hard to remove. I would like to razor knife the lip or drill it very carefully, but I need confirmation before doing so if it's not normal. I then cleaned out the nozzle and saw light through it, which is hard to see in the pic. Everything else looks great and I can't find anything wrong here besides the Teflon fitting.

Braddock, I thought I was in the clear after my changes, due to having the same exact problems with under extruding as you, but now they are back! After about 8 good quality prints that I could walk away from, my nightmare is back. We will definitely get to the bottom of this. I started thinking that the STL files I downloaded were bad, so I sat down and starting drawing them from scratch and once I pressed print, they starting failing after the first 20-30 layers. The under extrusion was so bad it was printing in air with nothing coming out. I will be taking apart the entire hot end tonight once again and posting pics and my findings.

AaronAlai I would post it on Youmagine or thingiverse, but I'm not finished with the entire design. I'm making an adjustable wall mount bracket, the sleeves for the bearings, and the knobs. If you would like, I can post it up there for you to download what I have so far. Let me know.

So far, I have been able to print a number of objects 4 times faster than before and they come out with the same quality as before. The same print that took 8 hours now takes me 1.5 hours. What a difference, I will post some pics soon.

Spool Adapter Multi-Step Something I had to print to get away from the tension issues of the stock spool holder. This runs super smooth spinning on 608 bearings and it's fully adjustable to other spool sizes and expandable to multiple spools on one holder. When changing filament it automatically goes right back on the roll the way it came off with no hassles of a bird's nest.

Nice 0235! I had many issues to deal with for the past two weeks so my parts have been coming along extremely slow, but I think i'm almost back on track, so I'll post some pics of my current progress.

illuminarti First let me say, thank you for all of your help and patience with my previous issues/posts. I have been dealing with heavy under extrusion issues. I have been adjusting the speed, temperature, and flow during prints when I start to see under extrusion taking over and always seem to get different results with inconsistencies. I wanted to wait until I had some more time to go over everything before posting back here. There are always entire layers missing in the print which makes it useless because I can just break it apart. I think I finally found the culprits to the majority of my issues. I say culprits because I believe I have had two problems the entire time. The first one is the spool holder that comes with the UM2. I believe the one that comes with the UM2 is a horrible design. I never thought it would actually be the reason for such issues. The second issue is with the netting that goes from the bottom of the extruder, up to the hot end. During prints it tends to move around and I noticed that the filament was rubbing up against the netting causing extra friction, along with the spool holder friction. These two simple issues have been haunting me for the past month. I came to this conclusion after designing a new spool holder and testing it out with 0 tension being pulled by the extruder. The design uses 4 printed parts, some 608 bearings from old roller blades, the plastic sleeves connecting both bearings, some 1/4" all thread rod, and a couple knobs with nuts sealed inside them. This allows the use of 1-3 rolls of filament at one time. It also can be used with different sized spools and it has free motion both ways. Even when changing filament, the filament automatically goes back on the roll instead of sprawling out. (Also made a couple wall mount brackets to slide the feet into) Since the spool was made I tried the same orange filament with multiple prints and it has worked flawlessly! I finally got my first glimpse of how this printer is supposed to work. I still need to do some more testing, but I have noticed a huge difference already.

I've had this UM2 for about a month now and I have spent more time fixing problems than actually printing. When I unboxed it the Y axis rod was completely dislodged from the side panel and bearing. (most likely shipping, it was an easy fix) All of the belt pulleys were loose and the rods were moving in and out of the case holes. (no problem, very easy fix) Both of my side fans were not working from the get go. (one pin in each connector was pulled out of the connector, easy fix) The Bowden tube was moving up and down where it is supposed to be secured into the hot-end. Some prints look fantastic once they start and 5-6 hours in they completely fail or something happens to where I have to abort the print. A couple of times the nozzle spit out pure liquid blobs of plastic all over the print without changing the temperature. I've had multiple clogs in the Teflon fitting and nozzle, which could only be unclogged by taking everything apart. (I have become quite efficient at doing this). My extruder seems to eat up the filament at random times. Another issue is the act of aborting a print! The newest software update 14.1 is totally messed up when aborting. The lights turn off, the screen goes black, the build plate stays put and doesn't move back down, and the hot-end stays put against the buildplate. (I have updated my PC and printer with the latest updates) I haven't been printing with crazy settings. Has anyone else been having these issues? What am I missing?

After more testing I found another issue that wasn't apparent before. I printed all of these gears pretty much perfectly and left the machine running overnight to finish the final gear on the front right side of pic. I wasn't quite sure what had happened, so I tried the change material option to remove the filament to see if it might be another clog. Before doing so, I noticed that the filament was ground down against the gear like the two times before. This made me aware that the extruder would not be able to retract the material properly so I gave it a slight pull to get the gears engaged on the cleaner filament. The material successfully retracted and here is what I noticed. The nubby shard was the culprit, keeping the filament from entering the bowden tube any further, causing the extruder to grind down the rest below that. Something didn't add up because I didn't find a clog and I didn't understand why the extruder gear ground up the filament. Illuminarti mentioned this issue. That's when I checked the bowden tube again (at both ends), and found that it was slightly loose where it sits into the teflon fitting in the hot-end. I can move it up and down about 1-2mm. The red clip is in properly and the gray coupling is probably messed up, even though I never removed it. Can I get these parts?

As far as I can tell, nothing is moving and I am extremely careful to put everything back the way it was. I usually take pictures before and after to make sure. Thank you for these settings, I will try them. I call it hitting home when we talk in terms of piping or fittings going all the way in to where they are supposed to sit. In every case that I took apart the hot-end, the teflon insulator has hit home, with the 1mm gap visible. This is something I made sure to do everytime.

I cleaned out the nozzle, yet again, and tightened the tension on the extruder bolt. Here is how my print came out: 100% infill and very little cleanup with very accurate gear teeth.

That's unfortunate! I take the glass off after every print and run cold water over the entire piece, then I simply tap the object with a tool that has an insulated handle (Example: Kleins) with the glass laying flat on the counter. The object usually pops right off with very little force.

I have another post under Clogged UM2 (http://umforum.ultimaker.com/index.php?/topic/3749-clogged-um2/&do=findComment&comment=31094) on how to clean the nozzle. I have done it 3 times in the past two weeks. I also had this problem with under extrusion and I think it might have been due to the feeding mechanism/extruder. I did adjust the extruder to have more tension because it seemed to eat up my plastic too easily. It's hard to see it in this pic, but I had under extrusion when printing this extruder every 20-30 layers: This print took 23 hours with 100% infill (3 parts) Once I had adjusted the extruder, I printed this motor gear which was almost perfect: This print took 6.5 hours with 100% infill

1. All fans are working. 2. What is a better setting for retraction other than the factory default settings? 3. Extruder is set to its default position all the way up. I'll try adjusting it. 4. I also have another PLA I'll try. Thanks for the info!

Maybe someone can help me understand why I am having these clogging issues. I'm using a UM2 with PLA only. In two weeks I have had to take the hot-end completely apart 3 times and the extruder I had to take apart twice out of those three times. The clogging is getting so bad that when I go to change the material, the extruder grinds away most of the matrerial so that it cannot be moved anymore. This is because the clog happens inside the nylon fitting that is attached to the nozzle. When this happens, I have to cut the PLA, remove the bowden tube from the extruder, then heat up the hot-end to 255C in order to remove the PLA by pulling it out with my bare hands. Anything less than that temperature will not suffice. I'm starting to get worried I might damage other parts if I have to keep using this method. I'm currently using the orange PLA from the Ultimaker store at these settings: Layers 0.08 Shell 0.8 Bottom/Top Thickness 0.8 Fill Density 100% (I'm making solid parts for my new printer) Speed 50 mm/s Support Brim Buildplate 55C Nozzle Temp 220C-221C Everything else is default Is it possible this temperature is too hot for too long so the heat is able to creep up to the PLA in the nylon? Is there a recommended nozzle temperature when doing 10+ hour prints? Also, I was wondering if anyone has come up with a chart for Layer quality and which speeds and temperatures are good to stick with at those different layer settings? If there is such a way to figure out these numbers? Something like this: Layer Height: .02=20-30 mm/s + temps? Layer Height: .04=30-40 mm/s + temps? Layer Height: .06=50-60 mm/s + temps? etc.........

Thanks for the heads-up gr5! I pulled back the mesh/netting and nothing appeared to be wrong, then I disconnected the white connectors and found that at least one pin was pulled out just enough to severe the connection to the fans. I did need a tool(needle-nose pliers to pull pins back), but it was still simple. I should have noticed the connectors located in the mesh without being told. Both fans are working as they should now!

I appreciate the info.