gr5

It takes at least 4mm for the pressure to be removed on the UM1. With only 4mm of retraction the filament is still pushing up on the top of the bowden at the top of the arc. More likely you are printing too hot - the cooler you print, the less stringing but retraction is important also: http://umforum.ultimaker.com/index.php?/topic/1872-some-calibration-photographs/

You aren't following your own topic. That's why. On top right corner of this page, look for "tonycstech". Click that and click "my settings" then "notification options" tab on left side, then check the first 8 checkboxes - most importantly the second one.

You don't have to clean out the stringy leftovers - just feed the filament back in and push them into the melt chamber.

Yes but then you wouldn't be able to print in that spot so you couldn't print full size prints unless they didn't reach that spot of the build plate. You would probably also have to cut a slot in the Z stage so that when the stage is all the way up it doesn't hit the wiper.

It's hard to tell that visually because the plastic squirts out the side - I think you would have to cut the part open to be sure. Before I posted, II looked at a few layers in your picture that stuck out and they appeared to stick out in 3 directions - towards the camera, to the left, and to the right. I couldn't check the back side (or even the sides) very well without having the object in my hand or seeing pictures from all sides. You should pick a layer visually and if it sticks out on all 4 directions then it's probably not your theory of "misaligned in XY direction". I mean your theory is pretty good - I've heard it before. But from the picture I'm not so sure I agree. Also this particular problem has come up before and a few people (not all of them) have been able to fix it by simply cleaning the z screw and z rods. Also you didn't mention what your layer thickness is.

This is a common problem and it is caused by Z innacuracies. So for example if you are doing 100 micron layers it might only move 70microns and get stuck. Then the extruder extrudes enough PLA for 100 microns in to a gap only 70 microns high and you get a bit squeezing out the side (over extrusion). Then on the next layer you might get 130 microns (meaning it caught back up - it moved the full amount finally) and on this layer you get underextrusion because it is extruding enough plastic for 100 microns but there is room for 130 microns worth. If your Z screw is dirty, clean it and regrease it with the green grease. Or just add a drop of green grease (a drop about 5mm across). Also put a few drops of thin petroleum oil on each of the 2 vertical rods. Do not grease the rods and do not oil the screw. Try to keep oil and grease away from the outside of the Z nut also - you don't want any lubrication between the nut and the wood (at least I don't think you do). What layer height are you doing? If you double the layer height you might get better results. Some people have also improved this exact thing by adding a 1kg weight to the bed (under the plastic bed). If you do that you will have to re-level of course.

When you reversed the 2 axes you got a mirror image because the problem is a combination of 2 issues - not one. Both of your axes have play. But only one tiny area of this part/gcode shows a "nasty displacement" because of the slicing and the order of how it approaches one small area of the part.

oops - I had it backwards. I did 0.8mm walls - you did 1.2mm walls. But that is one of the main differences that affected this print. This is fixed now in above post.

There are 2 issues: 1) You have some play (and so do I - in the long belts on my UM1). 2) The outer surface of the rectangle on the right is always drawn starting at the left corner in this picture and proceeds to the right. But sometimes the edge before is an inner skin on the same rectangle and sometimes it is the yellow square to the left that is drawn just before the outer edge of the right rectangle. When you sliced you did skin 1.2 and it somewhat randomly ended up with this horizontal "groove". When I sliced it I did 0.8 so there were 2 skin passes (instead of 3) and this changed the order of these 2 yellow rectangles so that for my print they were always perfect. So one fix (for this part only) is to do walls/skin 0.8mm thick. A better fix is to tighten your belts. You have to tighten both short and long belts. You said your belts were extremely tight but did you mean short or long? edit: fixed who did 1.2mm and who did 0.8mm.

Some people have reported that the PLA doesn't stick very well to ground glass because there are tiny air pockets that the PLA doesn't get into. This defeats the van der waals force apparently.

The gcode for the orange print I did with picture above is here: https://dl.dropboxusercontent.com/u/15273556/ultimaker/gcode/VersatzTest1a_0103_13.gcode

They completely updated the instructions with almost all new photos and made it a lot better this past year (2013) but of course it can always use an improvement. I think if it was updated with tricks used by people who actually assemble many machines then that would help.

Wow! I used your gcode exactly and... I got the same problem as you! My previous test was on the UM2 but I'm thinking it might be a slicing issue. I added arrows. The blue arrow shows the path before the displacement and the green arrow shows it after. I really don't think this is a temperature issue because it's shrinking on the short length, not the long. I think it's play/blackslash due to change in approach side of the wall. I'm wondering if my slicing settings swapped directions here - potentially because I had 1 more or fewer shell layers it may have reversed direction? That doesn't make sense. Or 20% versus 24% fill may have ended up at a different spot. Anyway I never delete anything so I can try: 1) Use my settings and slice up your stl (I don't have your short stl though - please post somewhere) 2) Look at the gcode for the print I printed (using repetier host - wonderful visual viewer for gcode) on the UM2 that came out fine I might not have time to do any of this until tonight.

I hate that this thread has been taken over. But anyway: @braddock - I think you need to tighten your extruder just a tiny bit. Rotate the screw head until the white part moves down and then back off a tiny bit. I think yours is so loose that sometimes it slips which grinds slightly and if you have too much retraction it gets worse until it takes a bite out of the filament. [illuminarti says: The conversation was subsequently moved into its own thread.]

I had to add shims as you can see in my photos. This way I made all the screws tight but it fight centered nicely on the Z nut. My Z nut is pretty tight. The design I believe is supposed to allow some play on the left side but that seemed unnecessary and I just adjusted the shims so everything was perfect and lined up and tightened up my Z stage very tight.

I had all of those problems: 1) My end caps are loose. In fact I took one off and the shaft came out about 3mm and just hangs there. I was going to do a better solution but it seems to be fine. 2) I added shims on both sides of the platform so that it was centered better on the Z screw. I will post pictures. I think yours might be slightly worse than mine even then.

Overhangs are tough to get "perfect". This is actually pretty good for this kind of an overhang. I would print slow, cool and thin layers and with as much fan as possible. Going below .1mm tends to make it worse but I would try it. Thin layers helps because that way more filament is touching the layer below and less filament is hanging over thin air. So set your flow back to 100%. Try 0.1mm layers, 20mm/sec, 190C. Now overhangs also have a problem where the plastic shrinks and lifts and then the print head hits the part you are printing - did you notice that at all? If you have that issue then keep things warm: 70C heated bed. Keep things warm by lowering fans possibly to 50% and maybe cover the front of the printer to keep the air warm that is close to the frog belly. If this isn't a problem then better to keep the fans at 100%. After you do that, try .05mm layers or .03mm layers to see if quality is better or worse. The limiting factor here is the Z drive. If you ask for .05mm layer but get .07mm on the movement of the bed, then you will be underextruding by a lot (and overextruding on the next layer where it corrects itself). So the lines can get *more* prominent when the layers are too thin. But the UM2 is pretty amazing so you might have no trouble going down to .03mm.

Can you send me your gcode file? I want to just print it exactly as it is - the gcode file. Make sure this isn't some slicing issue. I might have used a different version of Cura or a different setting. Maybe post the file somewhere and then post the link or I can email you directly if you want and you can reply with the file. I'll print it on my UM Original.

Yes. This is strange as hell. It sounds like play/backlash where the head keeps going. But it is happening on both axes. Could the nozzle just be loose? You tested that already, right? Or did you only check the entire head?

@braddock - I had the same thought as illuminarti - make sure this rear fan comes on the instant you power on the UM2 (even before the lights). It should always be on. If not you can get upper head clogs. My extruder won't grind the filament no matter what I do. This is because the amount of current sent to the extruder stepper is low enough so that it just doesn't have the power. I think your tension is either too high or too low. My tension is set so that the white square on the extruder is near the top - basically at the top. This is how it arrived and I haven't messed with it. Or maybe your knurled bolt on the extruder is a bit clogged up with material at this point? If you do an experiment, and heat up the head to 210, and then go into advanced and extrude filament "manually" (meaning using the "move filament" menu option). If you crank it out fast, does the extruder stepper move forward slowly and then skip/click/jump back suddenly quite a bit? It should slip back a lot - something like 1/3 turn. It should never let the filament slip - instead the whole motor should slip backwards suddenly.

I just made the same measurements but mine is put together so it is harder to measure perfectly. I measured and remeasured each measurement 6 times. I think my accuracy is around +/- .3mm. Maybe .2mm. I also have an assymettry similar to yours but the tabs fit pretty tight into the slots so I didn't file away more than maybe .25mm at the most. I didn't touch the tabs - only the slots. So top to bottom left side - same measurements as in your photo: 134 131.5 50.2 top to bottom right side: 134 132 50 I checked and rechecked. The slot and tab on the left panel seem about .5mm higher - the second tab/slot from the bottom - left panel. Possibly my left and front panels were out in the same directions as yours but slightly less maybe and I managed to force it together and the front and left panels came to a compromise half way between? I also noticed that particular slot is wider than most as though I filed the heck out of it but didn't know which of the 4 sides of the slot to file and filed the wrong edge (the edge towards the center of the left panel). There is a .5mm gap. If it were me I would just file off the 1mm in the slot or whatever it takes to get it to fit. I know the feet may then be not level so that might later be another adjustment. Actually it sounds like maybe your front panel is the part that is off at this point so maybe you should file off the tab in case you eventually get a new front panel.

Sander I think he is saying that he is keeping the t-slot screws loose for now -- you mentioned that tightening other t-slot screws could warp slightly and he is saying this shouldn't be a problem because they are all loose.

I just measured the rods on the UM Original and UM 2. They are all the same. 6mm rods got through the head. 8mm rods - four of them - go in the top 4 corners of the machine and are connected together by the long belts. The two vertical bars are 12mm. The z screw is much smaller on the UM2. edit: Here's the thing - I measured them all and verified they were the same and memorized the sizes but then my dog distracted me and we went outside in the deep snow which he loves to death. So I may have memorized one of the above measurements wrong. I'll double check later today. But the point is that the UM1 and UM2 rods are the same.

I measured the front bearing hole location (the one near switch #4) for both left and right panels and the blue dimension is 5mm, red distance is 8mm (+/- 0.5mm). So 5mm from the top, 8mm from the slot in the front of the machine. Incidentally I don't think i had to do tons of filing because of the paint. That paint was so thin I don't think I added more than 10 microns.

I can't answer that. Maybe they will. In the meantime all your photos and videos don't really show the problem - I know that when you put the left panel on top of the right the bearing hole looked way off. So maybe it was the right panel that was off all this time? You can wait and hope that they send you a complete new kit, but if it were me I would check the parts against the drawings and show EXACTLY what the problem is. What if they send you a complete new kit and it still doesn't fit? Whereas if you can say "on this panel, this hole was 10mm from the edge and needs to be 15mm" then the person shipping it to you can measure it and if it's wrong they won't ship it and they will try to find one the *does* fit properly. I mean if one panel is bad, maybe all the remaining kits are all bad? Maybe if they shipped you 10 kits they would all have the same problem. That's why it seems to me it's best to simplify the problem down to as simple a measurement as possible (with photo I suppose). I can tell you the distance from the bearing holes to my edges if that helps -- if you don't want to open up the pdf files with the laser cut drawings.