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G0 and G1 are identical commands and tell the printer to "go" or "go to" some location. You can specify all 4 axes or just one axes or anything in between. So G0 X50 Y50 Z15 Moves to that location with the nozzle 15mm above the bed. I don't know how wide your bed is and I don't know where 0,0 is for you. On UM printers 0,0 is front left and they are a little over 215mm wide so: G0 X200 Y0 Z15 is safe for a UM printer. To extrude it's the part where it does this: G92 E0 ;zero the extruded length G1 F200 E3 ;extrude 3mm of feed stock G92 E0 ;zero the extruded length again The G92's are important - that sets current position for an axis (in this case E axis to position zero). Without that you don't know where the E axis will move to - it depends where the E axis left off which might be at the 10 meter point from a previous print. The G1 F200 E3 moves 3mm of filament. The F200 is the feedrate which stays in effect for all subsequent G0 or G1 comnmands until F is mentioned again. It's in mm/minute so divide by 60 to get mm/sec. Or take your mm/sec value you want and multiply by 60. Does that answer all your questions?

ooh - tinkergnome just posted this in another thread - how to print below 180C... I never tried this myself.

Well first of all go as low as you can go in temp. Unfortunately that's basically 180C (if temp goes below 170C the firmware will stop the extruder). You might be able to do 175 C. 170C would be better but you would have to modify the firmware. So try 180C for now. In cura 2.* it's called "line width". not nozzle width. Make sure *all* line widths are set to 0.15. Changing just one of them is not enough. The worst thing that is likely to go wrong is that you clog it. Nothing serious. Ignore that bit about retraction distance and speed. That's set on the UM2 itself. 1mm is for non-bowden printers. Um2 needs retraction distance of about 4.5. Don't mess with that. Note that 3dsolex sells these I believe in packs of 4 because they can clog easily. But I've done a few prints an no clogs yet (only a few hours of printing though). Play with layer height and print speeds. Probably a layer height of 0.1 to 0.15 is best but I could be wrong. You want lots of fan. LOTS OF FAN. You might even want to lower bed temp to 60C. Or cooler. Maybe print on blue tape instead of glass and turn the bed off all the way. Maybe. If your object is too small the layer won't be able to cool because it's always basically in contact with the head at some portion. So print several objects at the same time so that while it's printing one object, the other has time to cool. I recommend at least 4 objects if they are smaller in cross section than your smallest finger. Put the objects you care least about at the left and right ends and the other objects in the middle. The objects on either end tend to do 2 layers in a row. Line the objects in a line left to right and close together so the fans blow on one while printing the next one over.

I'm a 3dsolex reseller. "race" means there is two paths for the filament to flow through before it exits the nozzle. This heats the filament more thoroughly and makes a big difference especially on the 0.8mm nozzle. You can print either faster or with lower temperature. There is no steel race nozzle. Steel is difficult to cut. "race" is difficult to cut. Put the two technologies together and it just doesn't work well apparently. You can get race ruby (aka everlast) but not race steel. "Matchless" usually means chrome plated but the ice nozzles aren't chrome plated. So it doesn't mean anything other than "nozzles made using a better machine such that they are produced to much higher tolerances and much better quality". For example the nozzle size (e.g. "0.4") is more likely to be milled versus laser etched on the side of the nozzle. Steel does not conduct heat as well so you have to print a bit hotter with steel nozzles. ICE coating is effectively teflon (I'm not sure exactly what it is but I think it's in the teflon family). It's extremely slippery and pla rarely sticks to it. It really does make a difference. The biggest noticable difference would be that you don't get black spots in your white prints where the filament burned a bit and later fell into the print. The ICE coating does not continue inside the nozzle. ICE nozzles should not be allowed to exceed 280C as that make the coating useless (no longer slippery). Yes you can print at least 10C cooler with "race" (not matchless) nozzles. In fact you might have to if you want the same quality as a non-race (you might get stringing if you don't do this).

Well you have a UM3 so the obvious answer is to use PVA support. There are other great answers above but... can't you rotate the model such that the edge that is pointing downwards in the photo is the bottom? Cura has the ability to rotate your part in any axes. Click on the part and on the left side choose the icon for rotating then click on a circle and drag.

It sounds like your STL files just have too many triangles. Consider reducing them somewhat with meshlab: http://www.shapeways.com/tutorials/polygon_reduction_with_meshlab I usually keep it under 100k triangles but your mileage may vary.

Go to cura settings (not profile settings) and there's a checkbox - make it so cura allows Z to go negative. Then click on the part and the "move" icon and set the Z to a slightly negative value. Maybe -0.1mm. This will probably fix your issue.

There are non profits who will send them letters from a real lawyer for you if you want. I think OSF maybe? (open source foundation)? Normal cura is on github. Just google it. It's probably in 2 parts: the gui and the backend. The backend is called something "engine". Like maybe curaengine - that does the actual slicing. It's in C for versions 15.X and 2.X. The gui is in python.

What I said above. That's the issue. Your bed NEVER goes down. The arduino thinks it is constantly hitting the Z limit switch. You got some junk down in there I think. Clean it out. Problem solved. I mean it goes down after hitting the head very hard but that's because it's moving very fast then and the steppers can occasionally go the wrong way if they are being pulsed fast enough and you shove them the wrong way to get going. So ignore that. Basically it is SILENT every time it should be going down. That is exactly what you expect when the limit switch is stuck in the down position.

There might just be some dust or hair in there blocking contact with one of the pads.

Did you change firmware recently? If so go in there and select "factory reset". That should fix things. If you could show a short video of the first few seconds when it moves the bed that would be helpful. There are several possibilities. It sounds like maybe your Z axis is moving backwards? Like it homes up instead of down? I can't think of anything that would do that other than a broken arduino chip which would require a new board. Or maybe it's not backwards but something is wrong with the Z switch. With power off pull the bed up and look at the long screw beneath. Then figure out where the hole is where that screw enters when the bed is down. Look in that hole - there should be a limit switch in there. If bits of plastic get in there they can interfere with the process. Make sure if you push the bed all the way down you hear it click. Other things can cause what you describe (you don't describe much so there are lots of possibilities). In particular if you loaded UM2 extended firmware on a regular UM2. Or if the microstepping jumper got messed up (it's on the white PCB under the printer in the center of everything). Show us a video of this slamming you speak of and what happens just before. That will help a lot with diagnosis.

@cgstudio - problems, problems. Well the infill being at .67 is probably a big part of the problem. Pressure equalizes for this slow printing volume and then it suddenly has to speed up on a single pass wall with .8mm extrusion. The tiny holes are caused because of underextrusion. So I would fix these with 3 changes: 1) Set infill width same as line width 2) Either set line width to .9mm (if you are doing it in one pass then it should be over extruded a bit) 3) Or even better set line width to 0.8 and inner shell to the same and do two passes (2 instead of 1). This will slow your print down a lot - two passes will be almost twice as slow so option 2 might be preferred at a small cost in qualitiy. As well I don't see any retraction settings. Cura 2.7 has a bug where it does a retraction on layer change. Uncheck that. Now for the bumps. Just slow it down. I would experiment while it's printing - try a speed multiplier from the UM3 TUNE menu of 75% and 50% and values in between if you want to learn more to see what speed causes those bumps. 30mm/sec speed should be pretty safe as long as *all* printing speeds are at 30mm/sec (don't want to print infill faster and then over extrude when starting the shell).

I don't know why it would move the bed down and up unless you had one of the "hop" options enabled in cura. Check cura for that - cura has ability to search for a setting. But I doubt that is related. Well if you suspect heat - try putting something heavy on the bed - around 5kg - maybe a brick or hand weight. Put it in the back of the bed after printing is started and see if your "scale distortion" gets worse or better. It should not make any difference. PLEASE PLEASE PLEASE also post photos of your prints and maybe a video of the "two displacements on one layer" thing you are talking about.

I guess I need more information. When cura slices a single layer it loops up all the line segments into loops or "islands". Typically a layer only has one island but very very often there are many islands on a given layer. Normally there is a retraction when leaving one island to go to another island. Now that we have the word "island" defined... Are you saying it finishes an island, moves the z axis, then retracts, then moves to a new island? or something else. I think there is some limited control over what order things are done - shell first or shell last for example. This might affect this stringing you are talking about. Maybe a picture would help.

"shell" is the total thickness of the outer walls (not including the infill pattern). outer wall is the thickness of the outer most pass. Usually it should be exactly the same or a little less than the nozzle width. There are inner shells as well. I don't know what skin is. There is a something about "top skin". I don't know what that is exactly. I have that always set to 0.

You can definitely get it better. You probably need to go down to 170C or 160C. But the printer won't let you go down to 170C so it would require a firmware change. I know you tried a few different versions of PLA (it's really more about the additives that make the color) but some colors behave better. White is probably the most difficult to print regardless of brand. I prefer PHA/PLA but for this unusual print (I guess all prints are special?) I think the PHA will make it string more. Lower layer height doesn't always increase quality - especially as you found out for this model. The 0.2mm version looks the best - those whispy strings at the top can be removed very easily - in fact trying to keep those strings attached to the print over the next year would be difficult. Did you play with retraction distance? I use 4.5mm on my UM3 (defaults I think to 6.5mm). As long as the bowdens are fixed in place (doesn't move up and down at either end - feeder or head) then personally I think 4.5mm works best but I could be wrong.

I'm confused. You want to *uncheck* retract at layer change. In general you can improve underextrusion and stringing issues by cooling the temperature by 10C and set ALL printing speeds (especially infill speeds) to 30mm/sec.

Did you check that the third/rear fan is working? I think that's on the list above.

>No I did not use the move function but the function of > putting 10 mm of filament trough the feeder in tinkergnome firmware. That's what I meant. I call that the MOVE function. >Yes I did the cold pull and even removed the olson block completely >and took a peak inside but all is normal. TFT isolated has been replaced >for new one also. But did you stick some filament up through the bottom (while cold)? Left image shows not enough tension. Right shows too much. You want it part way between.

After the eclipse is over and she starts narrating again, there are sped up videos showing the shadow pass over the clouds. In the first 2 sped up clips it approaches and then 2 clips of the sun coming back. Always it moves right to left. I you watch them a few times it gets very obvious. Stare only at the clouds. The ones in the left of the frame of the first clip are best and all across right to left of the south viewing clips. If you listen with the sound cranked you can hear some kind of insect making "night time noises".

I went to see the total solar eclipse last month and my daughter took footage from 4 different gopros and stitched and edited into a really nice video - more about the people than the eclipse - I think she did an excellent job (she has created about 70 videos over the last 3 years so she is getting pretty good - she has 2 other channels). It's a very intense event. Both my daughters cried. It's not what one expects. This is my third total eclipse. We went with 130 other people from the Boston astronomy club (atmob). Anyway eclipse part starts at 3 minutes in - I'm the guy in the yellow shirt. Skip to 3 minutes!

Are you talking about the cracked blocks? I fixed it by printing one of these: https://www.youmagine.com/designs/cracked-slide-block-cap I have done about 100 prints after adding this cap and it's doing fine.

Is this the black feeder or the white one? Are you sure you got the tension screw installed right? The head goes below a wall, not above (for both black and white feeders). I guess you know it is correct if you can adjust the pressure to the half way mark. Here's a photo with the black feeder at the weakest tension. You want it half way usually. Pushing 70mm when asking for 100 is normal if you are using "MOVE" menu command because it's easy to get the pressure too high and the feeder can slip (you hear a click) or the filament can slip/grind a bit (nothing to hear). Did you try doing a cold pull, removing the nozzle, letting it cool and inserting filament through the open olsson block? That can tell you a lot!

12.5V - not connected to printer. That's definitely a faulty brick. Don't throw it away. I had one like that and 4 days later it was still bad and a month later is was good again. I've been using it since. This bricks are strange.

How low did you go in temperature? (and can you go into your profile settings for this forum and mark that you have a UM3?). I'm doing some prints right now on a UM3 and had to lower by 10C to stop stringing. Don't be afraid to go all the way down to 180C. Although I have to say the final picture looks quite good as far as strings are concerned. Towards the end (top) it stopped retracting because Cura won't let you retract more than about 20 times on the same spot of filament (or you can grind the filament - in fact I usually set this to 10). So I think you were successful.