gr5

It's time to re-level your bed I suspect. I now do it before every print and if it hasn't moved it's trivial. But the bed tends to droop over time. Especially the front edge. Even if I *do* level I still watch while the skirt is printed - screwdriver in hand - and sometimes make tiny adjustments while it prints the skirt. A good skirt should be smooth and flat on top. If there is too much space the filament comes out shaped like a tube or string and doesn't stick well. If there is too little space - well on blue tape it can come out like above where there are spots with zero filament and spots with blobs coming out. On flatter surfaces (glass, kaptop tape, aluminum) it basically just doesn't come out or is so thin it's barely visible.

Post the cura log file please. Daid might reply if you do that. Or there might be hints in there.

There's three possibilities I think. Either the steppers skipped as illuminarti suggests which would probably be fixed by tightening the set screws (all 6 for each axis). Or the plexiglass may have moved (I doubt it) or the 3rd possibility which I think happened here is that the frisbee came loose off the bed. You should be able to tell better than us if this 3rd possiblity happened. In your photo it looks like the frisbee is off the blue tape and outside of the normal build area. Also it's very rare for X *and* Y to slip at the same time (same layer). Large parts have a tendency to warp and the edges lift slowly off the tape. This would be the worst when you are printing the underside of the frisbee (the top from this view). When it is printing those solid layers and they cool they shrink and pull very hard and warp the sides of the frisbee up off the tape. You can fix this by putting down fresh blue tape and cleaning well with isopropyl alcohol. This makes the blue tape AMAZINGLY sticky. Also it's helpful to set the skirt distance to zero and add 4 or more loops ("line count") of that. This makes it harder for air to get under the part and continue lifting it off the bed. I have no idea how skirt and support will interact and it might not work properly. So after slicing make sure the skirt is touching all around the frisbee and that it and the support structure don't interfere with each other.

If you had assembled it yourself you wouldn't have any confusion. This is the part of the instructions that describes in detail how to level and adjust the height of your bed home position: http://wiki.ultimaker.com/Ultimaker_rev.3_assembly:_Mounting_the_electronics#Step_10:_Checking_and_aligning_the_Z-homing_switch Please save a link to these instructions as you will at some point need to take apart and understand every single wire and bolt in your ultimaker. You are pretty much guaranteed to have other issues. In fact you should check for loose bolts right now. It sounds like your Z limit switch came loose.

I haven't needed to adjust the z limit switch since my first day of printing. I always just adjust the 4 screws. I use paper as my spacer. You should be able to slide the paper in and out under the nozzle at all 4 corners but not so loose that you can't tell how big the gap is. You should be able to slide the paper under the nozzle with one hand, kind of pushing it under. If it gets stuck and wrinkles then you probably don't have enough of a gap. When you print the very first layer it should be *almost* touching the print bed such that the first layer is squished flattish. Not rounded beads. But if it's ripping the tape your levelling is way off.

The price for the wear and tear of the ultimaker and your time is probably much higher than the price of the materials. Plus it may take you 2 or 3 tries to get it right.

Yes, well this is the weakness of the ultimaker. Moving the feeder farther away means the head can move much faster. I've seen photos of other people who did just what you say - suspended the feeder above the ultimaker with string. But I still think you can get good results if you keep experimenting. Maybe your spring should be tightened on your feeder so you can get down to 200C or so? Make sure you print at lower speeds - e.g. 50mm/sec with .2 layer or 100mm/sec with .1 layer when going under 200C.

Let me clarify that - I can't print 190C at 200mm/sec. But the speed doesn't affect stringing for me - just the temp. The retraction feature is the key thing and then secondarily, lowering the temp keeps the nozzle from leaking - even a little.

One would think. But I can print very slow and still get no stringing easily by lowering my temp to 190C. I wish you would post a picture. I assume you are talking about very minor stringing at 225C. I get absolutely zero stringing at 190C with 4.5mm retraction enabled. At 200C sometimes I get stringing, sometimes I don't and it's very minor. I can print at 200mm/sec or 20mm/sec and it makes no difference.

I'm glad you are happy. For layers that take more than around 20 seconds you shouldn't need the fans. But when you have layers that can print in 2 seconds - for example the antennas on the top of the ultimaker robot - then fans help a lot. With my fans on at 100% I can print 5 second layers no problem. If I print much faster (say 1 second layers) it looks like crap even *with* the fan. I have been meaning to test with the fan on and the fan off. Will test that eventually. Sooo - don't throw away your fans just yet. I'm sure you will have plenty of parts in the future where the top most layers print in under 5 seconds.

There was a bug in Marlin where you could ask for a retraction speed of for example 40 and it would actually do something more like 10mm/sec. This bug was fixed in the latest Marlin but a speed of 40mm/sec is much much too fast apparently. So lower your retraction speed in your slicer (e.g. Cura) and stick with your new Marlin.

1) Don't print thicker than .2mm or faster than 100mm/sec for your first print. 2) Consider raising the temperature to 230 just to figure this out although 200C is normally fine. 3) Are you getting clear teeth marks in the filament? Your feeder needs to be very strong. Try tightening the feeder and maybe examining this bolt: http://wiki.ultimaker.com/Ultimaker_rev.3_assembly:_Material_feed_mechanism#Step_2:_Drive_bolt_assembly I had to play with the washers and add my own washers to get this bolt to line up as well as in the picture. I did not follow the directions by the time I was done with it. Look at the picture at the bottom of this page. This is *good* teeth marks: http://umforum.ultimaker.com/index.php?/topic/291-extruder-calibration/page-3

Unless you really are invested in this mentally I wouldn't get it for a class. It took me maybe 20 hours to get all the kinks out. What I thought was perfectly assembled ended up having a slightly loose set screw, a rubbing belt (that looked fine) and didn't know about using isopropyl alcohol for the first 20 prints. It can be very frustrating. 20 extra hours for a teacher might be months or a year unless you take it home and spend 2 hours every night for a week. Other people have occasionally gotten a defective part that wasn't obvious, made a mistake in assembly, miswired motors, and more. But it's also very rewarding. If you are willing to bring it home and tinker with it until it works nicely, and if you are the one who kicks off every print manually, then it could be great. If you go for it, be prepared to have to take pictures and post them on this forum, but you *will* eventually get it working if you do that and follow all the advice. It just might take tens of hours. I'm thinking in a CAD/architecture class it would be fun to print the kid's house designs (with removable roof or missing roof of course!). However I think the UM really is amazing for artists.

Your brim looks too thin - you should relevel using a piece of paper. I think you started printing with the z stage too high by maybe .1mm. This can grind your filament and cause all kinds of trouble. However this has nothing to do with what you are complaining about because it printed the base of your part just fine and by the time it got to the trouble section you are fine. Rather than rebuild marlin, consider just lowering the retraction speed to 25 as illuminarti suggested. You probably already have the latest Marlin as I believe it came with cura 13.13. Watch the retraction wheel and see if it seems insanely fast and makes bad noises. If so, lower it by another factor of 2X. This is a very strange printing problem to me.

FYI - it's important that the first layer is *pushed* into the tape slightly. The initial string of PLA coming out should be wider than it is tall. If it looks cylindrical then you need to raise up the bed slightly. You don't want the first layer sitting slightly above the tape. Next time just *barely* clean the blue tape with isopropyl so it doesn't stick so well. lol. Also you only have to use higher temp and slower printing on the very first layer. The rest doesn't make any difference. PLA sticks to PLA just fine at any temp >=190C and any speed. In fact people who use heated beds often turn the bed *off* after the first layer is done printing.

Yes, you only need the hex file. You can use Cura or other software. I think I used pronterface but they both do it. Also I think the arduino IDE can possibly do it also. It's strange you had to do all this stuff. I didn't have to do any of it. I just followed the build instructions on some website - it was basically just a few button clicks. No editing. Not sure why you had to do so much editing. My only editing was Configuration.h. I think I might have followed these directions: http://reprap.org/wiki/Marlin#Configuring_and_compilation:

Oh - also I would expect very little ringing on rounded corner prints, yet you seem to have rounded corners and still have ringing. Something strange here. Maybe belts are *too* tight?

In theory, tightening or loosening the belts don't eliminate "ringing". It changes the frequency. The resonant frequency is a function of belt tension, and mass of the print head. Other things can dampen the ringing e.g. if the rubber in the belt isn't a perfect spring and has higher resistance at certain frequencies. I would expect the rubber to act less springy at high frequencies but I don't know how high is high frequencies. So if you tighten the belt to exactly twice the current tension I would still expect ringing but closer together. It seems to me we should be able to add a tiny box of loose sand or similar to the print head to help reduce ringing. The energy from the ringing would shake the sand and warm it up slightly and dampen the ringing. You can also reduce the ringing by reducing the acceleration and/or the "jerk". But this slows down prints. Be aware that if you change these values you have to save them or they will get lost when you power cycle marlin. You could add them to your "start gcodes" or you could modify them using the ulticontroller. The amount of ringing on your prints is small enough for me that I don't mind it at all. If you want perfect prints one thing you can do is sandpaper the lines off and then paint with a thin coat of automobile primer spray paint. This is a common, standard spray paint found at auto parts stores. The problem with only sanding is you get a dull finish where you sanded. Some people reheat the plastic to get it shiny again. Some people use a solvent, but solvents for PLA are rare but you can google about this. It's not 100% clear to me if your vertical lines comes from: 1) ringing (which should fade out left to right - this is most likely but hard to tell in your pictures) 2) STL - some stl models have vertical lines in them - visible in the cad software. 3) oscillating plastic due to high temp. Unlikely but details here: http://umforum.ultimaker.com/index.php?/topic/1872-some-calibration-photographs/ Other slicers (not cura - try kisslicer) let you modify the vertical seam so it's on a different random position on each layer. I prefer to have it in the same spot every time so I can rotate my part to have that hidden. Don't use Joris setting to remove vertical seam unless you have a simple solid with no holes or cavities (a cup is really the only thing you can print with Joris) as Joris can wreck a print for anything more complicated than a cup.

I have no idea about temperature and noise. The voltage going to the z stepper is probably a little higher is my guess but I'm not an expert. I wouldn't worry too much - these steppers are very tough. The X axis is connected to the rear side of the ultimaker which is a large piece of wood and I would expect that to be louder. Did you use the newer black plastic spacers for the x motor? Or did you use the wooden spacer? Supposedly the black plastic spacers are quieter.

This happens to me a lot so I usually print with the ulticontroller. Much more reliable. I don't have an answer for you, sorry. Oh - I found it helps if I set the print temp to 0 because it most often loses connection when waiting for print head temperature to stabilize.

Having rapid movements doesn't reduce stringing much and there are so many other things to control - it's easier to just speed up and slow down everything. If you print from Cura you can control 3 or 4 separate speeds I believe (walls only, fill only, etc.). You also can control "flow" live as you print. This is handy e.g. if you want the bottom layer perfect (no gaps, no overlap).

If you want to get rid of stringing alltogether, around 5mm is about right for retraction. Don't tell it to "extra length on start" and keep your temperature low. See this: http://umforum.ultimaker.com/index.php?/topic/1872-some-calibration-photographs/

Marlin tries to move X,Y,E (and occasionally Z) together. the gcode sets the desired speed in X,Y,E and marlin splits the move into 3 sections: accel, constant speed, decel. Often it never gets to the desired speed so there is just 2 sections: accel, decel. Marlin looks at things like jerk and max acceleration and picks the limiting acceleration (usually XY, but possibly E) and limits acceleration on *all* axes so that as you might think of it, it travels in a *straight* line from one point in 4 dimensional space to the next point. If it didn't make it a straight line, then you would get overextrusion in one section and underextrusion in another section of a given segement. So I don't think the problem is with the software. However, there is a lag or delay in when you tell the extruder to move and when the filament comes out or stops coming out. The extruder controls the pressure in the head almost more than the actual amount of extrusion. Maybe someday Marlin will model this but it's complicated as it depends on the type of filament, pressure, hole size, etc.

@TigrouxMaker If you read the Configuration.h file there is a commented part with a table with all numbers for the thermistors. There you can read that 1 (as in #define THERMISTORBED 1) stands for 100k thermistors. So nothing strange there. For a 100k thermistor the settings are ok. No!!! "6" is also a 100k thermister and that is the epcos one.

You want your pulley set screws very very tight. So tight you think you might almost break something. Make sure all 5 pulley set screws are tight. The 5th one is the most likely problem one - on the motor. Daid's idea of using a sharpie marker is very smart. You could also consider lowering your jerk and acceleration values, but it would be a shame to do that to fix a simple mechanical problem. There's a tiny probability that the voltage to your X stepper is too low. I really doubt this is it. The safest and simplest test would be to swap the X and Y drivers (they just unplug and you can switch them). If you do this, make sure power is off and remove all static electricity from your body before touching any electronics by not wearing a sweater and touching ground first.