stephenbrooks

Hi, Got it moving again. Loosened the screws on the bearings and it turns out the plate can slide quite a bit back and forth (by a millimetre or so) relative to those screws. So I moved it towards the front of the machine and away from the back: I noticed there's hardly any clearance between the build plate and the back of the machine, so I pulled it forwards as much as possible before re-tightening those 8 screws. Now the build plate can raise and lower just fine. However, I just tried printing again (after re-levelling the plate) and the plate still stops the same ~1.5mm short of the nozzle when it rises! I'm starting to wonder if it's a weird software error that misses steps. [edit] Oops! Wait, this is my fault! I was about to try and hack the .gcode file to force it to move the Z to the correct place (and along the way found this nice manual), when I saw this: So that looks like my ~mm gap. Looking more carefully at the model in Cura, I then saw this: So long story short, my model was at fault. The printer is now printing another model just fine! The fundamental reason for the error was that the software I use to generate the STL files sometimes leaves rogue vertices after cut operations. These are usually joined to zero-area triangles that don't show up in renders unless I specifically plot them: So, Cura was seeing that vertex and thinking it was the base of my model, and trying to plot the rest floating in thin air. Thanks to everyone who helped. I now know how the Z stage works and how to disassemble it, which might come in useful later anyway.

Well, I disassembled it, did my best to clean the Z-nut and bearings. Then tonight I reassembled it but now the plate won't go all the way to the bottom. When it gets about an inch above the lower limit the Z stepper motor makes a loud hum/whirr noise for a few seconds and then the printer says "Error: Z switch broken". It's completely jammed and I can't get it to move. Is there a risk of this from over-tightening the screws? I made sure I did them up tight because I thought that would help. I guess I could unscrew the bearings and maybe the nut again.

I'm guessing the brass one in the middle (screwed in from below) is the z-nut and the sleeves on either sides are the bearings. I unscrewed the right-hand bearing and it snags near the top of the rod if I try and move it up and down (haven't tried the left one yet). Feels like ball bearings jamming up. I see gr5 in one of your linked threads recommending the fix here is to take the faulty bearing(s) off and clean them out? The z-nut screws feel very tight, even though there's perhaps 0.3-0.5mm play in the plate if I push it from below. So I don't think I can tighten those 4 screws from below any more than they are already. [Later...] OK, got the bearing off one of the Z rods (and the rod slid out of the bottom of the machine). I can run it up and down and can feel the bearing snagging periodically. How exactly do I clean it out? (I'm a little afraid to introduce moisture). Alternatively, I guess I could order replacements.

This is getting interesting: I have a grinding noise when I move the plate down (and the Z screw rotates), but not when it goes up. There is some play when I push underneath the plate - of this sort of millimetre level too. The plate moves up a small amount before the Z screw starts to move. Where is the Z nut so I can tighten it? Do I have to remove that back plate again?

I wonder if it's possible to hack the .gcode files to put in some additional Z steps (upwards) at the beginning of the print? At least that way I could still use my printer.

OK, undid the screws. The plate took a bit of prying to get up but underneath there didn't seem to be any problems: The other place I looked is the Z switch recessed down in the bottom. I wondered if some debris had got in there but it doesn't seem like it. Could it even be some weird software problem where it's not remembering the number of Z steps to the top? I doubt it because it happened spontaneously. The only other thing I can think of is that when the plate rises it's fairly quiet but when it lowers there's a bit of crackling noise. I haven't had a *good* look around the Z stepper motor and Z switch since I've not removed the base plate yet.

My Ultimaker 2 had been printing quite happily for a while but today when I tried to print, the bed would stop 1-2mm short of the nozzle, so of course the filament didn't stick. I tried re-levelling the bed and it was time to lubricate the Z-screw (6 months), so I did that and put the bed up and down a few times. However, no matter how many times I re-level the bed, when I go to actually print, it stops 1-2mm short of how high I want the bed to be! The only thing I can think of is there's some debris around the screw, but there's this box with "Ultimaker 2" written on it at the back of the platform that hides part of the screw, maybe something dropped down there? Any ideas would be appreciated.

I found the skirt lines=0 option in Cura just now, re-levelled the build plate to be a bit closer to improve adhesion (hopefully the glassier base means no individual ones popping off) and it's going OK so far I'm printing these "all at once" layer by layer rather than one at a time. I may also try using the glue rather than just cleaning the build plate. Never had to use glue so far, but perhaps with this many small objects, guaranteeing adhesion would be good.

My hot end feels quite secure. I'm trying again, main problems with curling are on the first layer where it's putting down "strings". Some of the stuff sticks to the nozzle and of course when it's on there it's hot so it's sticky and starts sticking to other nearby filament and ends up destroying everything. This time I paused during the first layer when I saw lots of plastic on the nozzle to clean it off. Fingers crossed. I'm doing a challenging print with 60 small components tiled across the whole bed area, printing all at once. I've actually managed this 7 times before with a 48 component tiling that was almost as big. [edit] Actually... The problem is in this first step that seems pointless: I told Cura I didn't want a brim, but it still draws a circle around each component. It's actually laying down these circles that causes the problem! Once the inner parts are filled, they stick better. I'll see if I can get a picture.

Interesting you mention the cold pulls going into the very tip. Here's what I got:

Both my printers have this problem now. On the UM2E+ sometimes the filament curls around to the right so much it sticks back to the nozzle, making a loop. Then the plastic stuck to the nozzle can end up dragging other lines around on the first layer. I also see it when pushing the plastic through the heated nozzle by hand during the atomic method: the extruded filament likes to curl in one direction. (This is sometimes associated with worse print quality and a bit of underextrusion) Is this a common thing, and is it related to the PTFE coupler - or the nozzle? I tried the atomic method of cleaning on the UM2E+ and got a black ring around the plastic 12mm from the tip when I cold-pulled it out.

Do you have a preferred brand of PLA? So far Ultimaker's $70 filament works fine. Most of 3D universe's $38 filament is good (in my work UM2E+ printer at least). A colleague bought some $20 filament from who-knows-where and it prints but it's brittle as anything.

Meltiness seems to be material-dependent: 3D universe grey PLA gave better detailing on the top layers. My blue PLA from the same company seems oddly "gummy", I don't know if it's low melting point or some other aspect of the consistency.

OK, I put it back together and it's printing again now. Infill looks good. Top of the print is still a bit "melty". The nozzle of the Olsson block sticks out weirdly but looking at pictures on the web it's supposed to be like that. I also noticed the entrance to my PTFE coupler is slightly lopsided. The filament goes through OK, I think, but on one occasion where I was feeding in filament with a squared-off end, it caught on the side.

Well, tried WD-40 on the stuck temperature sensor, pulled on it some more and the wires ripped out but the outer shell stuck in the brass block. So replacing the temperature sensor it is. I've installed the spare temperature sensor. This went quite well, although re-threading it through the black cable sleeve was kind of painful. Then I continued to install the Olsson block (as my old head had the remains of the old temperature sensor stuck in it). This also went fine until I failed at the last hurdle: the fan shroud wouldn't go back on easily. That picture (NB: in a mirror) shows the temperature sensor and heater cable going into the new Olsson block. The heater cable is turning a horribly tight 90 degree bend and is fraying. This is because it conflicts with the back of the metal fan shroud when I put it back on. I've checked I can't push the heater in any further (when the block is unscrewed) and getting the Olsson block nozzle centered in the shroud hole requires this conflict. Do I just take pliers to the back of the fan shroud metal and bend it out a bit? It doesn't seem to be that important.

Oops! I wondered if that might be the case. Was following this video https://ultimaker.com/en/resources/18016-disassembling-the-hot-end and realised it didn't actually specify which was which. I'd been assuming the order mentioned in the text was the same as the video... My home one was only a plain UM2, but looking at the materials again, yes it does (and I guess this means my work one also came with a spare). Good, this might be simpler than I thought. I'll try the suggestion in the guide of "applying WD40" to get it out, and if that doesn't work I'll try to follow the instructions you linked to for replacing the sensor. I've got some titanium drill bits that go through metal and was wondering the same thing, but I'll try non-destructive methods first. Also if I take the sensor out with the block stuck on it anyway during replacement, it'll be easier to drill out and maybe I could recover a working temperature sensor from it.

Well, the good news is that my UM2 printer came with not only an Olsson block but four different-sized nozzles too (it was from fbrc8). The bad news is that at the step where I'm supposed to take the temperature sensor and heater out of the brass nozzle block, the temperature sensor came out fine but my heater is completely stuck (see photo below). It looks a bit burnt around the edges. I tried quite a bit of pull force and wiggling it around but only succeeded in pulling the insulation up the cable and fraying the metal weave a bit. The only thing I can try is switching the heater itself on, although I can't see that helping much since the heater would presumably expand... Can I buy a replacement heater and cable? Not sure where the other end of the cable is connected so might be difficult to replace.

Yes, it came bundled with my UM2. Haven't installed it yet, though. But since I've disassembled the head once already I might as well try it next time... Right, but hearing that tocking noise is bad, right? It's a symptom of under-extrusion, insufficient temperature or a blocked nozzle? (At least that's what I guessed). I'll upload a photo of it if I take the head apart again. I think mine is solid white, I'll have to check. So there's an improved version? Good to know, I might buy one. Ah! OK, I didn't know you could set all those others to blank or zero. Kind of weird that this is the default "Fast" setting in quickprint in Cura for the UM2, then! :( Unless they expect people to also raise the temperature when they print on "Fast". Like I said, the UM2E+ "Fast" default is more conservative and uses no more than 60mm/s (3.6mm^3/s).

Since I've got a U2E+ at work as well as the U2 original at home, I can now eliminate a few possibilities: The white PLA printed just fine on the U2E+, on the same model, temperature and even the same speed settings, since I copied those more conservative settings (in the post above) to the U2 at home. My caliper arrived and the "2.85mm" filament measured as something like 2.85x2.86mm, or ridiculously close to what it should be. ...so I don't think it's the material. I might also try the original grey PLA at home to confirm. That means there's something wrong with my home (U2) printer. I'm interested by your comment that acetone will only remove ABS and not PLA from the nozzle. Certainly, my brief attempt at ABS gave me a lot of grief with burnt particles of that clogging up the nozzle. So perhaps I'll try disassembling the print head again and following the (slightly scary) instructions that say to reheat the head, while keeping it from burning adjacent wires, and then clean out with a Q-tip or similar. My home printer is showing a bunch of symptoms right now that might all boil down to an underextrusion problem: incomplete infill, too "melty" appearance at the standard 210C temperature. If I reduce to 200C, the detail improves but the feeder motor "tocking" comes back and the first layer no longer sticks to the build plate reliably any more, despite it being level and clean (maybe not enough material to stick).

Brief question about print speed: the Cura software has two tabs of print speed settings on "full settings" mode: [u2E+ settings shown here] ...but changing the overall print speed in the "Basic" tab does not seem to do anything. I only got changes by changing the individual numbers in the "Advanced" tab, which are different, such as reducing the infill speed.

Thanks for your reply. I've taken a break from it but will continue to fiddle around later and will post here when I do. The feeder motor stopped clicking so much after I cleaned the nozzle, so perhaps I made some progress there. I had to look up what a "knurled sleeve" is It's the thing rotates, grips and pushes the filament right? I'll look when I go home. How would I know if it was loose? Layer height of 0.15mm and nozzle 0.4mm I seem to remember (the default for "Fast" in Cura for Ultimaker 2). I wonder if this a material-specific problem: basically it doesn't print at the fast speeds (100mm/s for infill on "Fast" on Ultimaker 2). I should try changing back to my silver PLA and see if that works. It's supposed to be 2.85mm, but this was "cheap" PLA filament from 3D universe and not the Ultimaker's own brand, so maybe I don't trust it. I've ordered a micrometer to accurately measure the diameter (didn't have one but I wanted one anyway). The other thing I notice is that "Fast" in Cura on the Ultimaker 2+ is not as fast (60mm/s for fill) as on the Ultimaker 2, plus they increased the fill factor from 10% to 18%. Not sure if using the 2+ settings on the 2 would improve matters, I did something similar already and it did improve the quality. Finally I've been getting some "melting" on fine details with this white filament. I'd guess that means I'm printing too *hot* (currently at the default 210C) although this was on very small layers so perhaps I should increase the layer cooldown time.

Well, setting the extrusion flow factor to 125% made the print look "healthier" with less gap behind the wall layers. I'm now wondering if my filament (White PLA from 3D universe shop) is a smaller diameter than stated but I don't have a micrometer/caliper to check. The "tocking" from the motor has now stopped after my various cleaning operations and the filament comes out of the nozzle a bit more at the start of the print (still not as easily as other materials though). I tried changing the print settings from 10% fill (a rather large internal grid) and 50mm/s maximum speed to 18% fill (the Ultimaker 2+ setting) and 25mm/s maximum speed since my print is small anyway. This made *almost* solid internal grid walls, albeit a bit thin looking. I saw on the web once a table of ideal print settings for different filament colours and suppliers but can't seem to find it. At the moment hoping a combination of further reduced max print speed and increased flow (or correcting the filament diameter) will get a passable print.

For educational purposes, I took the nozzle apart. Doesn't appear to be anything wrong with the PTFE coupler - a bit blackened but the shape is fine. With the coupler out I poured some acetone through the nozzle in case there was residual plastic there. Put it all back together... exactly the same! Under-extrusion particularly on high speed moves like making the internal grid in prints. I noticed there is a tuning setting for print speed. I thought printing slower might help, but it seems too little material comes out even when it's going slower. If it's not the nozzle I figure it must be the feeder motor, unless my filament is bad for some reason.

My total printing time is 161h57m. Although some of that was when I experimented with ABS (didn't print much with it though as ultimately fairly unsuccessful), it was mostly PLA. The end on the nozzle is perfect. The one in the extruder is less perfect but I checked pushing a filament through and there is no excessive resistance from the tube. No this is a new spool! It actually got a bit worse when I changed to white PLA from grey PLA (although it was also under-extruding with the grey). I tried upping the temperature but that didn't help the extrusion at all and it extruded fine manually. Somehow the feeder motor is not pushing enough? Should I change the tension setting on the motor? If so, in what direction? When I re-loaded the material just now, as soon as the filament started to extrude from the nozzle, the feeder motor kept skipping back (about once per second making a "tock" noise). I just tried a print and although the initial extrusion looked hopeful, it under-extruded during printing (with the same settings that have been fine before), with the internal structure grid not forming solidly.

Hi, My Ultimaker 2 (original) at home has started making a clicking sound from the filament feeder motor quite a lot. Recently I found that I was getting severe underextrusion, even though if I push the PLA manually into the nozzle (at the default print temperature of 210C), it goes through fine with a bit of pressure. When the printer tries to do the same using its motor e.g. at the beginning of a print, it is unable to push any through now. (NB: I've done the atomic method through about 5 cycles to clean the nozzle). I've not changed the feeder motor tensioner at all since I bought this, but which way should I change it? Less or more tension? Currently the filament that's been through the motor has a regular pattern of tiny holes down one side, but otherwise is not distorted or ground up.