gr5

I don't think dis assembly is the issue as one can use qtips, tweezers, popsicle sticks - things like that. The issue is finding a glue that works well on the inside material of the UM2 sides. I don't know what glues work.

don't hit it with a hammer! You will probably damage the stepper. There is a "set screw" or "grub screw" or whatever you want to call it in the pulley. Try shining a bright light in there. It should be the same hex size (or torx) as all the other screws all over the UM2 (except the fan screws). It will take a huge force to loosen that tiny screw. Tighten with similar torque.

Try clicking in the top right corner where it says "aviphysics" then look through those options for a validation option. It should send an email to the email you registered (edited for privacy): **homa*@tha***ec*.com If you can't figure it out, I can email you I suppose and try to do it from my end - not sure how though.

Your forum account? This "aviphysics" account?

I always select "ask me before upgrade" in the settings so I don't know if I messed up this time or if my setting got overridden or what. I have 6 computers actively used in the house, typically every day. Of course this error only occurred on the one closest to the UM but what about java update? What about firefox update? Some other update? photoshop? I like power saver but I don't want it enabled during a print so I have to remember to turn it off and on all the time. Most software updates won't reboot my computer but I'm not 100% sure which ones might and might not. Besides I had other USB issues, sometimes it would stop for no apparent reason. So I don't use USB anymore. UM even officially said it's not supported on the UM2 even though it's mostly the same software and hardware.

To me the problem could still be many things grouped into 3 categories, problems with extruder, problems with nozzle, other friction (bowden tube, kinking, spool). I'm leaning towards problems with nozzle (such as burnt, black PLA coating the inside), but I haven't ruled out the extruder yet. You could do a definitive test to rule out the extruder. Put a short length of PLA in the extruder and with the servo powered up pull on the PLA until the servo slips or the PLA slips. Pull by using weights. When done measure the weights. If you do this test I will duplicate it on my machine. You could even repeat the test with the filament 90% through the bowden if you want to see if that makes any difference (I doubt it).

The above image is from your video near the end. The red arrow points to the gap between the pulley and the motor. That is huge on your machine compared to mine. That gap should be as small as possible without touching the motor. It's about 1/2 mm on mine. I suggest you remove the left back metal cover (just one screw to remove that screws directly into a threaded nut like piece welded to the cover), remove the motor, loosen the pulley on the motor and slide it closer to the motor without touching it, tighten it back up (very very tight) and then put it all back together.

The photo of the scissor lift is interesting. Note though that if you rotate 1mm worth of movement on the screw horizontally, the vertical movement is only equal to 1mm when things are at 45 degree angles. The formula is something like: (Z position)^2 = (arm radius)^2 - (servo position)^2 So Marlin might need this formula included in a few places. Or you could fudge it with a cura plug in that changes all the Z heights.

The belts all go around pulleys. The pulleys each have a set screw to hold them firmly to the rod they are on. You can loosen a pulley and then slide it to the correct position. I'm not quite sure what you mean but the short belt from the stepper motor to the pulley above - that black belt should not touch anything on the way. If it does you will get problems. Also be aware that if the long belts are too tight you can get too much friction on a given axis. Inside the side blocks are belt tighteners. I've never opened mine though. I have no idea what they look like.

I recommend getting ulticontrollers for both of you. I found USB printing to be too unreliable. I know it costs another $200 or so but it's worth it. It is soooo worth it. Then your PC can crash, cura can crash, whatever. It won't matter if you are printing from the SD card on the ulticontroller. I did a print once and one hour into it it died because windows wants to do a stupid (I hate you microsoft) windows update including reboot with no warning when I started the print. I assume there was a popup message saying something like "rebooting in 20 minutes, press Yes to reboot now, No to reboot later".

I have a notebook I keep under the bed with notes on every print and I also save all the gcode files in a particular location so I can look at the settings I used for a print months or years later. It has been very helpful many times for things I thought I would never forget... but did.

I've never used those "quickprint" settings. Ever.

The head has amplifiers for the thermocouples. Measure the voltage at the top of the head. The voltage should be equal to the temp such that 5V = 500C 0V=0C 0.200V = 20C (room temp) If the voltages are around 200mv at the top of the print head then it's likely the wiring from there - usually the wiring right there above the print head as it gets the most stress when the head moves around.

You're going to love the new heated bed if UM ever comes out with it for the UM Original!

I don't know if the glass will work any better. Better to print in a warmer room. Or to make a heated chamber - printing in a 50F basement is part of the problem. Put a light bulb under the bed, enclose 3 sides in saran wrap. Put a box over the top. Let it heat up to 80F before you start printing.

Another possibility: your floor is thinner than your layer height.

So who needs a floor? Gosh you guys want everything Just kidding. It's most likely the model. Cura doesn't like internal edges. One thing you can try is when in cura instead of looking at layer view, try xray view. Anything red is a "problem". Your model should be "manifold" (I think that is the right word). It should have no holes and no internal walls. It should be obvious what is inside and what is outside. So for example did you put a bottom on your floor if you look at it in sketchup from below? Anyway if you don't want to fix it in sketchup you can try the various "fix horrible" settings. Usually 1 or 2 of the first 3 checkboxes fixes it. Never check both A and B. This means there are 11 different combinations. I know it's a lot to check so probably easier to fix the model in sketchup. If after reading this and looking at it in xray view and checking the bottom you are still stumped, post the sketchup file somewhere and I'll look at it.

I have the exact same 4 questions and would especially like to see a photo of the extruder system.

Yes this is normal. I've never ground filament on my UM2. It slips back. The stepper loses steps. If you increase the current too high then the extruder grinds the filament which trust me is much worse!

Yes, clearly your black/green are backwards. Here is the photo from the official assembly instructions. Also don't forget to swap the endstops back how they were meant to be:

You can loosen the end caps while you print if you want. That's the easiest of all the things to try. That and a drop of oil on each of the 6 rods. Also can be done while printing.

http://umforum.ultimaker.com/index.php?/topic/4118-blocked-nozzle/?p=33691

PLA melts around 170C. Teflon around 250C. Get the temp in between and the PLA will melt and you can wipe it away with paper towel. Even boiling water is plenty hot enough to remove the PLA.

Do not let acetone anywhere near your lenses. That's all I have to say.

Mostly about printing on hot glass - but stuff about printing on cold glass also: http://umforum.ultimaker.com/index.php?/topic/3404-printing-on-glass/