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stephenbrooks

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  1. 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.
  2. 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.
  3. 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.
  4. 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?
  5. 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.
  6. 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.
  7. 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.
  8. 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.
  9. 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.
  10. Interesting you mention the cold pulls going into the very tip. Here's what I got:
  11. 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.
  12. 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.
  13. 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.
  14. 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.
  15. 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.
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